Merge pull request '0.5.0 -- tuples and more optimizations' (#12) from 43-tuple-return into master

Reviewed-on: #12

.github/copilot-instructions.md

@@ -80,10 +80,14 @@ cargo test --package compiler --lib -- test::tuple_literals::test::test_tuple_li
 
 ### Quick Compilation
 
+!IMPORTANT: make sure you use these commands instead of creating temporary files.
+
 ```bash
 cd rust_compiler
 # Compile Slang code to IC10 using current compiler changes
 echo 'let x = 5;' | cargo run --bin slang
+# Compile Slang code to IC10 with optimization
+echo 'let x = 5;' | cargo run --bin slang -z
 # Or from file
 cargo run --bin slang -- input.slang -o output.ic10
 # Optimize the output with -z flag

.gitignore

@@ -1,5 +1,6 @@
 target
 *.ic10
+*.snap.new
 release
 csharp_mod/bin
 obj

Changelog.md

@@ -2,10 +2,10 @@
 
 [0.5.0]
 
-- Added support for tuple types
+- Added full tuple support: declarations, assignments, and returns
-- Added support for tuple returns from functions
+- Refactored optimizer into modular passes with improved code generation
-- Added support for ignoring tuple values
+- Enhanced peephole optimizations and pattern recognition
-- Fixed various compiler bugs
+- Comprehensive test coverage for edge cases and error handling
 
 [0.4.7]
 

rust_compiler/Cargo.lock

@@ -23,7 +23,7 @@ version = "0.7.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "891477e0c6a8957309ee5c45a6368af3ae14bb510732d2684ffa19af310920f9"
 dependencies = [
- "getrandom",
+ "getrandom 0.2.16",
  "once_cell",
  "version_check",
 ]
@@ -73,7 +73,7 @@ version = "1.1.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "40c48f72fd53cd289104fc64099abca73db4166ad86ea0b4341abe65af83dadc"
 dependencies = [
- "windows-sys",
+ "windows-sys 0.61.2",
 ]
 
 [[package]]
@@ -84,7 +84,7 @@ checksum = "291e6a250ff86cd4a820112fb8898808a366d8f9f58ce16d1f538353ad55747d"
 dependencies = [
  "anstyle",
  "once_cell_polyfill",
- "windows-sys",
+ "windows-sys 0.61.2",
 ]
 
 [[package]]
@@ -135,6 +135,12 @@ version = "1.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "bef38d45163c2f1dde094a7dfd33ccf595c92905c8f8f4fdc18d06fb1037718a"
 
+[[package]]
+name = "bitflags"
+version = "2.10.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "812e12b5285cc515a9c72a5c1d3b6d46a19dac5acfef5265968c166106e31dd3"
+
 [[package]]
 name = "bitvec"
 version = "1.0.1"
@@ -278,6 +284,18 @@ dependencies = [
  "tokenizer",
 ]
 
+[[package]]
+name = "console"
+version = "0.15.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "054ccb5b10f9f2cbf51eb355ca1d05c2d279ce1804688d0db74b4733a5aeafd8"
+dependencies = [
+ "encode_unicode",
+ "libc",
+ "once_cell",
+ "windows-sys 0.59.0",
+]
+
 [[package]]
 name = "crc32fast"
 version = "1.5.0"
@@ -293,12 +311,28 @@ version = "0.1.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "56254986775e3233ffa9c4d7d3faaf6d36a2c09d30b20687e9f88bc8bafc16c8"
 
+[[package]]
+name = "encode_unicode"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "34aa73646ffb006b8f5147f3dc182bd4bcb190227ce861fc4a4844bf8e3cb2c0"
+
 [[package]]
 name = "equivalent"
 version = "1.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "877a4ace8713b0bcf2a4e7eec82529c029f1d0619886d18145fea96c3ffe5c0f"
 
+[[package]]
+name = "errno"
+version = "0.3.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "39cab71617ae0d63f51a36d69f866391735b51691dbda63cf6f96d042b63efeb"
+dependencies = [
+ "libc",
+ "windows-sys 0.61.2",
+]
+
 [[package]]
 name = "ext-trait"
 version = "1.0.1"
@@ -334,13 +368,19 @@ version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "320bea982e85d42441eb25c49b41218e7eaa2657e8f90bc4eca7437376751e23"
 
+[[package]]
+name = "fastrand"
+version = "2.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "37909eebbb50d72f9059c3b6d82c0463f2ff062c9e95845c43a6c9c0355411be"
+
 [[package]]
 name = "fluent-uri"
 version = "0.1.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "17c704e9dbe1ddd863da1e6ff3567795087b1eb201ce80d8fa81162e1516500d"
 dependencies = [
- "bitflags",
+ "bitflags 1.3.2",
 ]
 
 [[package]]
@@ -366,6 +406,18 @@ dependencies = [
  "wasi",
 ]
 
+[[package]]
+name = "getrandom"
+version = "0.3.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "899def5c37c4fd7b2664648c28120ecec138e4d395b459e5ca34f9cce2dd77fd"
+dependencies = [
+ "cfg-if",
+ "libc",
+ "r-efi",
+ "wasip2",
+]
+
 [[package]]
 name = "gimli"
 version = "0.32.3"
@@ -428,6 +480,32 @@ dependencies = [
  "rustversion",
 ]
 
+[[package]]
+name = "insta"
+version = "1.45.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "983e3b24350c84ab8a65151f537d67afbbf7153bb9f1110e03e9fa9b07f67a5c"
+dependencies = [
+ "console",
+ "once_cell",
+ "similar",
+ "tempfile",
+]
+
+[[package]]
+name = "integration_tests"
+version = "0.1.0"
+dependencies = [
+ "anyhow",
+ "compiler",
+ "il",
+ "indoc",
+ "insta",
+ "optimizer",
+ "parser",
+ "tokenizer",
+]
+
 [[package]]
 name = "inventory"
 version = "0.3.21"
@@ -465,6 +543,12 @@ version = "0.2.178"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "37c93d8daa9d8a012fd8ab92f088405fb202ea0b6ab73ee2482ae66af4f42091"
 
+[[package]]
+name = "linux-raw-sys"
+version = "0.11.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "df1d3c3b53da64cf5760482273a98e575c651a67eec7f77df96b5b642de8f039"
+
 [[package]]
 name = "logos"
 version = "0.16.0"
@@ -505,7 +589,7 @@ version = "0.97.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "53353550a17c04ac46c585feb189c2db82154fc84b79c7a66c96c2c644f66071"
 dependencies = [
- "bitflags",
+ "bitflags 1.3.2",
  "fluent-uri",
  "serde",
  "serde_json",
@@ -678,6 +762,12 @@ dependencies = [
  "proc-macro2",
 ]
 
+[[package]]
+name = "r-efi"
+version = "5.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "69cdb34c158ceb288df11e18b4bd39de994f6657d83847bdffdbd7f346754b0f"
+
 [[package]]
 name = "radium"
 version = "0.7.0"
@@ -711,7 +801,7 @@ version = "0.6.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ec0be4795e2f6a28069bec0b5ff3e2ac9bafc99e6a9a7dc3547996c5c816922c"
 dependencies = [
- "getrandom",
+ "getrandom 0.2.16",
 ]
 
 [[package]]
@@ -800,6 +890,19 @@ dependencies = [
  "semver",
 ]
 
+[[package]]
+name = "rustix"
+version = "1.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "146c9e247ccc180c1f61615433868c99f3de3ae256a30a43b49f67c2d9171f34"
+dependencies = [
+ "bitflags 2.10.0",
+ "errno",
+ "libc",
+ "linux-raw-sys",
+ "windows-sys 0.61.2",
+]
+
 [[package]]
 name = "rustversion"
 version = "1.0.22"
@@ -928,6 +1031,12 @@ version = "0.1.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e3a9fe34e3e7a50316060351f37187a3f546bce95496156754b601a5fa71b76e"
 
+[[package]]
+name = "similar"
+version = "2.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bbbb5d9659141646ae647b42fe094daf6c6192d1620870b449d9557f748b2daa"
+
 [[package]]
 name = "slang"
 version = "0.5.0"
@@ -1014,6 +1123,19 @@ version = "1.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "55937e1799185b12863d447f42597ed69d9928686b8d88a1df17376a097d8369"
 
+[[package]]
+name = "tempfile"
+version = "3.24.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "655da9c7eb6305c55742045d5a8d2037996d61d8de95806335c7c86ce0f82e9c"
+dependencies = [
+ "fastrand",
+ "getrandom 0.3.4",
+ "once_cell",
+ "rustix",
+ "windows-sys 0.61.2",
+]
+
 [[package]]
 name = "thiserror"
 version = "2.0.17"
@@ -1140,6 +1262,15 @@ version = "0.11.1+wasi-snapshot-preview1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ccf3ec651a847eb01de73ccad15eb7d99f80485de043efb2f370cd654f4ea44b"
 
+[[package]]
+name = "wasip2"
+version = "1.0.1+wasi-0.2.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0562428422c63773dad2c345a1882263bbf4d65cf3f42e90921f787ef5ad58e7"
+dependencies = [
+ "wit-bindgen",
+]
+
 [[package]]
 name = "wasm-bindgen"
 version = "0.2.106"
@@ -1191,6 +1322,15 @@ version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f0805222e57f7521d6a62e36fa9163bc891acd422f971defe97d64e70d0a4fe5"
 
+[[package]]
+name = "windows-sys"
+version = "0.59.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1e38bc4d79ed67fd075bcc251a1c39b32a1776bbe92e5bef1f0bf1f8c531853b"
+dependencies = [
+ "windows-targets",
+]
+
 [[package]]
 name = "windows-sys"
 version = "0.61.2"
@@ -1200,6 +1340,70 @@ dependencies = [
  "windows-link",
 ]
 
+[[package]]
+name = "windows-targets"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9b724f72796e036ab90c1021d4780d4d3d648aca59e491e6b98e725b84e99973"
+dependencies = [
+ "windows_aarch64_gnullvm",
+ "windows_aarch64_msvc",
+ "windows_i686_gnu",
+ "windows_i686_gnullvm",
+ "windows_i686_msvc",
+ "windows_x86_64_gnu",
+ "windows_x86_64_gnullvm",
+ "windows_x86_64_msvc",
+]
+
+[[package]]
+name = "windows_aarch64_gnullvm"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "32a4622180e7a0ec044bb555404c800bc9fd9ec262ec147edd5989ccd0c02cd3"
+
+[[package]]
+name = "windows_aarch64_msvc"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "09ec2a7bb152e2252b53fa7803150007879548bc709c039df7627cabbd05d469"
+
+[[package]]
+name = "windows_i686_gnu"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8e9b5ad5ab802e97eb8e295ac6720e509ee4c243f69d781394014ebfe8bbfa0b"
+
+[[package]]
+name = "windows_i686_gnullvm"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0eee52d38c090b3caa76c563b86c3a4bd71ef1a819287c19d586d7334ae8ed66"
+
+[[package]]
+name = "windows_i686_msvc"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "240948bc05c5e7c6dabba28bf89d89ffce3e303022809e73deaefe4f6ec56c66"
+
+[[package]]
+name = "windows_x86_64_gnu"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "147a5c80aabfbf0c7d901cb5895d1de30ef2907eb21fbbab29ca94c5b08b1a78"
+
+[[package]]
+name = "windows_x86_64_gnullvm"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "24d5b23dc417412679681396f2b49f3de8c1473deb516bd34410872eff51ed0d"
+
+[[package]]
+name = "windows_x86_64_msvc"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "589f6da84c646204747d1270a2a5661ea66ed1cced2631d546fdfb155959f9ec"
+
 [[package]]
 name = "winnow"
 version = "0.7.14"
@@ -1209,6 +1413,12 @@ dependencies = [
  "memchr",
 ]
 
+[[package]]
+name = "wit-bindgen"
+version = "0.46.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f17a85883d4e6d00e8a97c586de764dabcc06133f7f1d55dce5cdc070ad7fe59"
+
 [[package]]
 name = "with_builtin_macros"
 version = "0.0.3"

rust_compiler/libs/compiler/src/v1.rs

@@ -1180,6 +1180,27 @@ impl<'a> Compiler<'a> {
             Some(name.span),
         )?;
 
+        // Pop the arguments off the stack (caller cleanup convention)
+        // BUT: If the function returns a tuple, it saves SP in r15 and the caller
+        // will restore SP with "move sp r15", which automatically cleans up everything.
+        // So we only pop arguments for non-tuple-returning functions.
+        let returns_tuple = self
+            .function_meta
+            .tuple_return_sizes
+            .get(&name.node)
+            .copied()
+            .unwrap_or(0)
+            > 0;
+
+        if !returns_tuple {
+            for _ in 0..arguments.len() {
+                self.write_instruction(
+                    Instruction::Pop(Operand::Register(VariableScope::TEMP_STACK_REGISTER)),
+                    Some(name.span),
+                )?;
+            }
+        }
+
         // pop all registers back (if they were backed up)
         if backup_registers {
             for register in active_registers.iter().rev() {

rust_compiler/libs/il/src/lib.rs

@@ -61,6 +61,7 @@ impl<'a> std::fmt::Display for Instructions<'a> {
     }
 }
 
+#[derive(Clone)]
 pub struct InstructionNode<'a> {
     pub instruction: Instruction<'a>,
     pub span: Option<Span>,

rust_compiler/libs/integration_tests/.gitattributes

@@ -0,0 +1,2 @@
+# Treat snapshot files as text
+*.snap text

rust_compiler/libs/integration_tests/Cargo.toml

@@ -0,0 +1,19 @@
+[package]
+name = "integration_tests"
+version = "0.1.0"
+edition = "2024"
+publish = false
+
+[dependencies]
+compiler = { path = "../compiler" }
+parser = { path = "../parser" }
+tokenizer = { path = "../tokenizer" }
+optimizer = { path = "../optimizer" }
+il = { path = "../il" }
+anyhow = { workspace = true }
+indoc = "2"
+insta = "1.40"
+
+[lib]
+# This is a test-only crate
+path = "src/lib.rs"

rust_compiler/libs/integration_tests/README.md

@@ -0,0 +1,92 @@
+# Integration Tests for Slang Compiler with Optimizer
+
+This crate contains end-to-end integration tests for the Slang compiler that verify the complete compilation pipeline including all optimization passes.
+
+## Snapshot Testing with Insta
+
+These tests use [insta](https://insta.rs/) for snapshot testing, which captures the entire compiled output and stores it in snapshot files for comparison.
+
+### Running Tests
+
+```bash
+# Run all integration tests
+cargo test --package integration_tests
+
+# Run a specific test
+cargo test --package integration_tests test_simple_leaf_function
+```
+
+### Updating Snapshots
+
+When you make changes to the compiler or optimizer that affect the output:
+
+```bash
+# Update all snapshots automatically
+INSTA_UPDATE=always cargo test --package integration_tests
+
+# Or use cargo-insta for interactive review (install first: cargo install cargo-insta)
+cargo insta test --package integration_tests
+cargo insta review --package integration_tests
+```
+
+### Understanding Snapshots
+
+Snapshot files are stored in `src/snapshots/` and contain:
+
+- The full IC10 assembly output from compiling Slang source code
+- Metadata about which test generated them
+- The expression that produced the output
+
+Example snapshot structure:
+
+```
+---
+source: libs/integration_tests/src/lib.rs
+expression: output
+---
+j main
+move r8 10
+j ra
+```
+
+### What We Test
+
+1. **Leaf Function Optimization** - Removal of unnecessary `push sp/ra` and `pop ra/sp`
+2. **Function Calls** - Preservation of stack frame when calling functions
+3. **Constant Folding** - Compile-time evaluation of constant expressions
+4. **Algebraic Simplification** - Identity operations like `x * 1` → `x`
+5. **Strength Reduction** - Converting expensive operations like `x * 2` → `x + x`
+6. **Dead Code Elimination** - Removal of unused variables
+7. **Peephole Comparison Fusion** - Combining comparison + branch instructions
+8. **Select Optimization** - Converting if/else to single `select` instruction
+9. **Complex Arithmetic** - Multiple optimizations working together
+10. **Nested Function Calls** - Full program optimization
+
+### Adding New Tests
+
+To add a new integration test:
+
+1. Add a new `#[test]` function in `src/lib.rs`
+2. Call `compile_optimized()` with your Slang source code
+3. Use `insta::assert_snapshot!(output)` to capture the output
+4. Run with `INSTA_UPDATE=always` to create the initial snapshot
+5. Review the snapshot file to ensure it looks correct
+
+Example:
+
+```rust
+#[test]
+fn test_my_optimization() {
+    let source = "fn foo(x) { return x + 1; }";
+    let output = compile_optimized(source);
+    insta::assert_snapshot!(output);
+}
+```
+
+### Benefits of Snapshot Testing
+
+- **Full Output Verification**: Tests the entire compiled output, not just snippets
+- **Easy to Review**: Visual diffs show exactly what changed in the output
+- **Regression Detection**: Any change to output is immediately visible
+- **Living Documentation**: Snapshots serve as examples of compiler output
+- **Less Brittle**: No need to manually update expected strings when making intentional changes

rust_compiler/libs/integration_tests/src/lib.rs

@@ -0,0 +1,222 @@
+//! Integration tests for the Slang compiler with optimizer
+//!
+//! These tests compile Slang source code and verify both the compilation
+//! and optimization passes work correctly together using snapshot testing.
+
+#[cfg(test)]
+mod tests {
+    use compiler::Compiler;
+    use indoc::indoc;
+    use parser::Parser;
+    use tokenizer::Tokenizer;
+
+    /// Compile Slang source code and return both unoptimized and optimized output
+    fn compile_with_and_without_optimization(source: &str) -> String {
+        // Compile for unoptimized output
+        let tokenizer = Tokenizer::from(source);
+        let parser = Parser::new(tokenizer);
+        let compiler = Compiler::new(parser, None);
+        let result = compiler.compile();
+
+        // Get unoptimized output
+        let mut unoptimized_writer = std::io::BufWriter::new(Vec::new());
+        result
+            .instructions
+            .write(&mut unoptimized_writer)
+            .expect("Failed to write unoptimized output");
+        let unoptimized_bytes = unoptimized_writer
+            .into_inner()
+            .expect("Failed to get bytes");
+        let unoptimized = String::from_utf8(unoptimized_bytes).expect("Invalid UTF-8");
+
+        // Compile again for optimized output
+        let tokenizer2 = Tokenizer::from(source);
+        let parser2 = Parser::new(tokenizer2);
+        let compiler2 = Compiler::new(parser2, None);
+        let result2 = compiler2.compile();
+
+        // Apply optimizations
+        let optimized_instructions = optimizer::optimize(result2.instructions);
+
+        // Get optimized output
+        let mut optimized_writer = std::io::BufWriter::new(Vec::new());
+        optimized_instructions
+            .write(&mut optimized_writer)
+            .expect("Failed to write optimized output");
+        let optimized_bytes = optimized_writer.into_inner().expect("Failed to get bytes");
+        let optimized = String::from_utf8(optimized_bytes).expect("Invalid UTF-8");
+
+        // Combine both outputs with clear separators
+        format!(
+            "## Unoptimized Output\n\n{}\n## Optimized Output\n\n{}",
+            unoptimized, optimized
+        )
+    }
+
+    #[test]
+    fn test_simple_leaf_function() {
+        let source = "fn test() { let x = 10; }";
+        let output = compile_with_and_without_optimization(source);
+        insta::assert_snapshot!(output);
+    }
+
+    #[test]
+    fn test_function_with_call() {
+        let source = indoc! {"
+            fn add(a, b) { return a + b; }
+            fn main() { let x = add(5, 10); }
+        "};
+        let output = compile_with_and_without_optimization(source);
+        insta::assert_snapshot!(output);
+    }
+
+    #[test]
+    fn test_constant_folding() {
+        let source = "let x = 5 + 10;";
+        let output = compile_with_and_without_optimization(source);
+        insta::assert_snapshot!(output);
+    }
+
+    #[test]
+    fn test_algebraic_simplification() {
+        let source = "let x = 5; let y = x * 1;";
+        let output = compile_with_and_without_optimization(source);
+        insta::assert_snapshot!(output);
+    }
+
+    #[test]
+    fn test_strength_reduction() {
+        let source = "fn double(x) { return x * 2; }";
+        let output = compile_with_and_without_optimization(source);
+        insta::assert_snapshot!(output);
+    }
+
+    #[test]
+    fn test_dead_code_elimination() {
+        let source = indoc! {"
+            fn compute(x) {
+                let unused = 20;
+                return x + 1;
+            }
+        "};
+        let output = compile_with_and_without_optimization(source);
+        insta::assert_snapshot!(output);
+    }
+
+    #[test]
+    fn test_peephole_comparison_fusion() {
+        let source = indoc! {"
+            fn compare(x, y) {
+                if (x > y) {
+                    let z = 1;
+                }
+            }
+        "};
+        let output = compile_with_and_without_optimization(source);
+        insta::assert_snapshot!(output);
+    }
+
+    #[test]
+    fn test_select_optimization() {
+        let source = indoc! {"
+            fn ternary(cond) {
+                let result = 0;
+                if (cond) {
+                    result = 10;
+                } else {
+                    result = 20;
+                }
+                return result;
+            }
+        "};
+        let output = compile_with_and_without_optimization(source);
+        insta::assert_snapshot!(output);
+    }
+
+    #[test]
+    fn test_leaf_function_no_stack_frame() {
+        let source = indoc! {"
+            fn increment(x) { 
+                x = x + 1;
+            }
+        "};
+        let output = compile_with_and_without_optimization(source);
+        insta::assert_snapshot!(output);
+    }
+
+    #[test]
+    fn test_complex_arithmetic() {
+        let source = indoc! {"
+            fn compute(a, b, c) {
+                let x = a * 2;
+                let y = b + 0;
+                let z = c * 1;
+                return x + y + z;
+            }
+        "};
+        let output = compile_with_and_without_optimization(source);
+        insta::assert_snapshot!(output);
+    }
+
+    #[test]
+    fn test_nested_function_calls() {
+        let source = indoc! {"
+            fn add(a, b) { return a + b; }
+            fn multiply(x, y) { return x * 2; }
+            fn complex(a, b) {
+                let sum = add(a, b);
+                let doubled = multiply(sum, 2);
+                return doubled;
+            }
+        "};
+        let output = compile_with_and_without_optimization(source);
+        insta::assert_snapshot!(output);
+    }
+
+    #[test]
+    fn test_tuples() {
+        let source = indoc! {r#"
+            device self = "db";
+            device day  = "d0";
+
+            fn getSomethingElse(input) {
+                return input + 1;
+            }
+
+            fn getSensorData() {
+                return (
+                    day.Vertical,
+                    day.Horizontal,
+                    getSomethingElse(3)
+                );
+            }
+
+            loop {
+                yield();
+                
+                let (vertical, horizontal, _) = getSensorData();
+
+                (horizontal, _, _) = getSensorData();
+
+                self.Setting = horizontal;
+            }
+        "#};
+
+        let output = compile_with_and_without_optimization(source);
+        insta::assert_snapshot!(output);
+    }
+
+    #[test]
+    fn test_larre_script() {
+        let source = include_str!("./test_files/test_larre_script.stlg");
+        let output = compile_with_and_without_optimization(source);
+        insta::assert_snapshot!(output);
+    }
+
+    #[test]
+    fn test_reagent_processing() {
+        let source = include_str!("./test_files/reagent_processing.stlg");
+        let output = compile_with_and_without_optimization(source);
+        insta::assert_snapshot!(output);
+    }
+}

rust_compiler/libs/integration_tests/src/snapshots/integration_tests__tests__algebraic_simplification.snap

@@ -0,0 +1,17 @@
+---
+source: libs/integration_tests/src/lib.rs
+expression: output
+---
+## Unoptimized Output
+
+j main
+main:
+move r8 5
+mul r1 r8 1
+move r9 r1
+
+## Optimized Output
+
+move r8 5
+move r1 5
+move r9 5

rust_compiler/libs/integration_tests/src/snapshots/integration_tests__tests__complex_arithmetic.snap

@@ -0,0 +1,45 @@
+---
+source: libs/integration_tests/src/lib.rs
+assertion_line: 158
+expression: output
+---
+## Unoptimized Output
+
+j main
+compute:
+pop r8
+pop r9
+pop r10
+push sp
+push ra
+mul r1 r10 2
+move r11 r1
+add r2 r9 0
+move r12 r2
+mul r3 r8 1
+move r13 r3
+add r4 r11 r12
+add r5 r4 r13
+move r15 r5
+j __internal_L1
+__internal_L1:
+pop ra
+pop sp
+j ra
+
+## Optimized Output
+
+j main
+pop r8
+pop r9
+pop r10
+push sp
+push ra
+add r11 r10 r10
+move r12 r9
+move r13 r8
+add r4 r11 r12
+add r15 r4 r13
+pop ra
+pop sp
+j ra

rust_compiler/libs/integration_tests/src/snapshots/integration_tests__tests__constant_folding.snap

@@ -0,0 +1,13 @@
+---
+source: libs/integration_tests/src/lib.rs
+expression: output
+---
+## Unoptimized Output
+
+j main
+main:
+move r8 15
+
+## Optimized Output
+
+move r8 15

rust_compiler/libs/integration_tests/src/snapshots/integration_tests__tests__dead_code_elimination.snap

@@ -0,0 +1,32 @@
+---
+source: libs/integration_tests/src/lib.rs
+assertion_line: 103
+expression: output
+---
+## Unoptimized Output
+
+j main
+compute:
+pop r8
+push sp
+push ra
+move r9 20
+add r1 r8 1
+move r15 r1
+j __internal_L1
+__internal_L1:
+pop ra
+pop sp
+j ra
+
+## Optimized Output
+
+j main
+pop r8
+push sp
+push ra
+move r9 20
+add r15 r8 1
+pop ra
+pop sp
+j ra

rust_compiler/libs/integration_tests/src/snapshots/integration_tests__tests__function_with_call.snap

@@ -0,0 +1,52 @@
+---
+source: libs/integration_tests/src/lib.rs
+assertion_line: 70
+expression: output
+---
+## Unoptimized Output
+
+j main
+add:
+pop r8
+pop r9
+push sp
+push ra
+add r1 r9 r8
+move r15 r1
+j __internal_L1
+__internal_L1:
+pop ra
+pop sp
+j ra
+main:
+push sp
+push ra
+push 5
+push 10
+jal add
+move r8 r15
+__internal_L2:
+pop ra
+pop sp
+j ra
+
+## Optimized Output
+
+j 9
+pop r8
+pop r9
+push sp
+push ra
+add r15 r9 r8
+pop ra
+pop sp
+j ra
+push sp
+push ra
+push 5
+push 10
+jal 1
+move r8 r15
+pop ra
+pop sp
+j ra

rust_compiler/libs/integration_tests/src/snapshots/integration_tests__tests__larre_script.snap

@@ -0,0 +1,223 @@
+---
+source: libs/integration_tests/src/lib.rs
+expression: output
+---
+## Unoptimized Output
+
+j main
+waitForIdle:
+push sp
+push ra
+yield
+__internal_L2:
+l r1 d0 Idle
+seq r2 r1 0
+beqz r2 __internal_L3
+yield
+j __internal_L2
+__internal_L3:
+__internal_L1:
+pop ra
+pop sp
+j ra
+deposit:
+push sp
+push ra
+s d0 Setting 1
+jal waitForIdle
+move r1 r15
+s d0 Activate 1
+jal waitForIdle
+move r2 r15
+s d1 Open 0
+__internal_L4:
+pop ra
+pop sp
+j ra
+checkAndHarvest:
+pop r8
+push sp
+push ra
+sle r1 r8 1
+ls r15 d0 255 Seeding
+slt r2 r15 1
+or r3 r1 r2
+beqz r3 __internal_L6
+j __internal_L5
+__internal_L6:
+__internal_L7:
+ls r15 d0 255 Mature
+beqz r15 __internal_L8
+yield
+s d0 Activate 1
+j __internal_L7
+__internal_L8:
+ls r15 d0 255 Occupied
+move r9 r15
+s d0 Setting 1
+push r8
+push r9
+jal waitForIdle
+pop r9
+pop r8
+move r4 r15
+push r8
+push r9
+jal deposit
+pop r9
+pop r8
+move r5 r15
+beqz r9 __internal_L9
+push r8
+push r9
+jal deposit
+pop r9
+pop r8
+move r6 r15
+__internal_L9:
+s d0 Setting r8
+push r8
+push r9
+jal waitForIdle
+pop r9
+pop r8
+move r6 r15
+ls r15 d0 0 Occupied
+beqz r15 __internal_L10
+s d0 Activate 1
+__internal_L10:
+push r8
+push r9
+jal waitForIdle
+pop r9
+pop r8
+move r7 r15
+__internal_L5:
+pop ra
+pop sp
+j ra
+main:
+move r8 0
+__internal_L11:
+yield
+l r1 d0 Idle
+seq r2 r1 0
+beqz r2 __internal_L13
+j __internal_L11
+__internal_L13:
+add r3 r8 1
+sgt r4 r3 19
+add r5 r8 1
+select r6 r4 2 r5
+move r9 r6
+push r8
+push r9
+push r8
+jal checkAndHarvest
+pop r9
+pop r8
+move r7 r15
+s d0 Setting r9
+move r8 r9
+j __internal_L11
+__internal_L12:
+
+## Optimized Output
+
+j 77
+push sp
+push ra
+yield
+l r1 d0 Idle
+bne r1 0 8
+yield
+j 4
+pop ra
+pop sp
+j ra
+push sp
+push ra
+s d0 Setting 1
+jal 1
+move r1 r15
+s d0 Activate 1
+jal 1
+move r2 r15
+s d1 Open 0
+pop ra
+pop sp
+j ra
+pop r8
+push sp
+push ra
+sle r1 r8 1
+ls r15 d0 255 Seeding
+slt r2 r15 1
+or r3 r1 r2
+beqz r3 32
+j 74
+ls r15 d0 255 Mature
+beqz r15 37
+yield
+s d0 Activate 1
+j 32
+ls r9 d0 255 Occupied
+s d0 Setting 1
+push r8
+push r9
+jal 1
+pop r9
+pop r8
+move r4 r15
+push r8
+push r9
+jal 11
+pop r9
+pop r8
+move r5 r15
+beqz r9 58
+push r8
+push r9
+jal 11
+pop r9
+pop r8
+move r6 r15
+s d0 Setting r8
+push r8
+push r9
+jal 1
+pop r9
+pop r8
+move r6 r15
+ls r15 d0 0 Occupied
+beqz r15 68
+s d0 Activate 1
+push r8
+push r9
+jal 1
+pop r9
+pop r8
+move r7 r15
+pop ra
+pop sp
+j ra
+move r8 0
+yield
+l r1 d0 Idle
+bne r1 0 82
+j 78
+add r3 r8 1
+sgt r4 r3 19
+add r5 r8 1
+select r6 r4 2 r5
+move r9 r6
+push r8
+push r9
+push r8
+jal 23
+pop r9
+pop r8
+move r7 r15
+s d0 Setting r9
+move r8 r9
+j 78

rust_compiler/libs/integration_tests/src/snapshots/integration_tests__tests__leaf_function_no_stack_frame.snap

@@ -0,0 +1,30 @@
+---
+source: libs/integration_tests/src/lib.rs
+assertion_line: 144
+expression: output
+---
+## Unoptimized Output
+
+j main
+increment:
+pop r8
+push sp
+push ra
+add r1 r8 1
+move r8 r1
+__internal_L1:
+pop ra
+pop sp
+j ra
+
+## Optimized Output
+
+j main
+pop r8
+push sp
+push ra
+add r1 r8 1
+move r8 r1
+pop ra
+pop sp
+j ra

rust_compiler/libs/integration_tests/src/snapshots/integration_tests__tests__nested_function_calls.snap

@@ -0,0 +1,107 @@
+---
+source: libs/integration_tests/src/lib.rs
+assertion_line: 173
+expression: output
+---
+## Unoptimized Output
+
+j main
+add:
+pop r8
+pop r9
+push sp
+push ra
+add r1 r9 r8
+move r15 r1
+j __internal_L1
+__internal_L1:
+pop ra
+pop sp
+j ra
+multiply:
+pop r8
+pop r9
+push sp
+push ra
+mul r1 r9 2
+move r15 r1
+j __internal_L2
+__internal_L2:
+pop ra
+pop sp
+j ra
+complex:
+pop r8
+pop r9
+push sp
+push ra
+push r8
+push r9
+push r9
+push r8
+jal add
+pop r9
+pop r8
+move r10 r15
+push r8
+push r9
+push r10
+push r10
+push 2
+jal multiply
+pop r10
+pop r9
+pop r8
+move r11 r15
+move r15 r11
+j __internal_L3
+__internal_L3:
+pop ra
+pop sp
+j ra
+
+## Optimized Output
+
+j main
+pop r8
+pop r9
+push sp
+push ra
+add r15 r9 r8
+pop ra
+pop sp
+j ra
+pop r8
+pop r9
+push sp
+push ra
+add r15 r9 r9
+pop ra
+pop sp
+j ra
+pop r8
+pop r9
+push sp
+push ra
+push r8
+push r9
+push r9
+push r8
+jal 1
+pop r9
+pop r8
+move r10 r15
+push r8
+push r9
+push r10
+push r10
+push 2
+jal 9
+pop r10
+pop r9
+pop r8
+move r11 r15
+move r15 r11
+pop ra
+pop sp
+j ra

rust_compiler/libs/integration_tests/src/snapshots/integration_tests__tests__peephole_comparison_fusion.snap

@@ -0,0 +1,34 @@
+---
+source: libs/integration_tests/src/lib.rs
+assertion_line: 116
+expression: output
+---
+## Unoptimized Output
+
+j main
+compare:
+pop r8
+pop r9
+push sp
+push ra
+sgt r1 r9 r8
+beqz r1 __internal_L2
+move r10 1
+__internal_L2:
+__internal_L1:
+pop ra
+pop sp
+j ra
+
+## Optimized Output
+
+j main
+pop r8
+pop r9
+push sp
+push ra
+ble r9 r8 7
+move r10 1
+pop ra
+pop sp
+j ra

rust_compiler/libs/integration_tests/src/snapshots/integration_tests__tests__reagent_processing.snap

@@ -0,0 +1,111 @@
+---
+source: libs/integration_tests/src/lib.rs
+expression: output
+---
+## Unoptimized Output
+
+j main
+main:
+s d2 Mode 1
+s d2 On 0
+move r8 0
+move r9 0
+__internal_L1:
+yield
+l r1 d0 Reagents
+move r10 r1
+sge r2 r10 100
+sge r3 r9 2
+or r4 r2 r3
+beqz r4 __internal_L3
+move r8 1
+__internal_L3:
+slt r5 r10 100
+ls r15 d0 0 Occupied
+seq r6 r15 0
+and r7 r5 r6
+add r1 r9 1
+select r2 r7 r1 0
+move r9 r2
+l r3 d0 Rpm
+slt r4 r3 1
+and r5 r8 r4
+beqz r5 __internal_L4
+s d0 Open 1
+seq r6 r10 0
+ls r15 d0 0 Occupied
+and r7 r6 r15
+seq r1 r7 0
+move r8 r1
+__internal_L4:
+seq r6 r8 0
+s d0 On r6
+ls r15 d1 0 Quantity
+move r11 r15
+l r7 d3 Pressure
+sgt r1 r7 200
+beqz r1 __internal_L5
+j __internal_L1
+__internal_L5:
+sgt r2 r11 0
+s d1 On r2
+sgt r3 r11 0
+s d1 Activate r3
+l r4 d3 Pressure
+sgt r5 r4 0
+l r6 d1 Activate
+or r7 r5 r6
+s d2 On r7
+l r1 d1 Activate
+s db Setting r1
+j __internal_L1
+__internal_L2:
+
+## Optimized Output
+
+s d2 Mode 1
+s d2 On 0
+move r8 0
+move r9 0
+yield
+l r10 d0 Reagents
+sge r2 r10 100
+sge r3 r9 2
+or r4 r2 r3
+beqz r4 11
+move r8 1
+slt r5 r10 100
+ls r15 d0 0 Occupied
+seq r6 r15 0
+and r7 r5 r6
+add r1 r9 1
+select r2 r7 r1 0
+move r9 r2
+l r3 d0 Rpm
+slt r4 r3 1
+and r5 r8 r4
+beqz r5 27
+s d0 Open 1
+seq r6 r10 0
+ls r15 d0 0 Occupied
+and r7 r6 r15
+seq r8 r7 0
+seq r6 r8 0
+s d0 On r6
+ls r15 d1 0 Quantity
+move r11 r15
+l r7 d3 Pressure
+ble r7 200 34
+j 4
+sgt r2 r11 0
+s d1 On r2
+sgt r3 r11 0
+s d1 Activate r3
+l r4 d3 Pressure
+sgt r5 r4 0
+l r6 d1 Activate
+or r7 r5 r6
+s d2 On r7
+l r1 d1 Activate
+s db Setting r1
+j 4

rust_compiler/libs/integration_tests/src/snapshots/integration_tests__tests__select_optimization.snap

@@ -0,0 +1,36 @@
+---
+source: libs/integration_tests/src/lib.rs
+assertion_line: 133
+expression: output
+---
+## Unoptimized Output
+
+j main
+ternary:
+pop r8
+push sp
+push ra
+move r9 0
+beqz r8 __internal_L3
+move r9 10
+j __internal_L2
+__internal_L3:
+move r9 20
+__internal_L2:
+move r15 r9
+j __internal_L1
+__internal_L1:
+pop ra
+pop sp
+j ra
+
+## Optimized Output
+
+j main
+pop r8
+push sp
+push ra
+select r15 r8 10 20
+pop ra
+pop sp
+j ra

rust_compiler/libs/integration_tests/src/snapshots/integration_tests__tests__simple_leaf_function.snap

@@ -0,0 +1,26 @@
+---
+source: libs/integration_tests/src/lib.rs
+assertion_line: 60
+expression: output
+---
+## Unoptimized Output
+
+j main
+test:
+push sp
+push ra
+move r8 10
+__internal_L1:
+pop ra
+pop sp
+j ra
+
+## Optimized Output
+
+j main
+push sp
+push ra
+move r8 10
+pop ra
+pop sp
+j ra

rust_compiler/libs/integration_tests/src/snapshots/integration_tests__tests__strength_reduction.snap

@@ -0,0 +1,30 @@
+---
+source: libs/integration_tests/src/lib.rs
+assertion_line: 91
+expression: output
+---
+## Unoptimized Output
+
+j main
+double:
+pop r8
+push sp
+push ra
+mul r1 r8 2
+move r15 r1
+j __internal_L1
+__internal_L1:
+pop ra
+pop sp
+j ra
+
+## Optimized Output
+
+j main
+pop r8
+push sp
+push ra
+add r15 r8 r8
+pop ra
+pop sp
+j ra

rust_compiler/libs/integration_tests/src/snapshots/integration_tests__tests__tuples.snap

@@ -0,0 +1,93 @@
+---
+source: libs/integration_tests/src/lib.rs
+assertion_line: 206
+expression: output
+---
+## Unoptimized Output
+
+j main
+getSomethingElse:
+pop r8
+push sp
+push ra
+add r1 r8 1
+move r15 r1
+j __internal_L1
+__internal_L1:
+pop ra
+pop sp
+j ra
+getSensorData:
+push sp
+push ra
+l r1 d0 Vertical
+push r1
+l r2 d0 Horizontal
+push r2
+push 3
+jal getSomethingElse
+move r3 r15
+push r3
+sub r0 sp 5
+get r0 db r0
+move r15 r0
+j __internal_L2
+__internal_L2:
+sub r0 sp 4
+get ra db r0
+j ra
+main:
+__internal_L3:
+yield
+jal getSensorData
+pop r0
+pop r9
+pop r8
+move sp r15
+jal getSensorData
+pop r0
+pop r0
+pop r9
+move sp r15
+s db Setting r9
+j __internal_L3
+__internal_L4:
+
+## Optimized Output
+
+j 23
+pop r8
+push sp
+push ra
+add r15 r8 1
+pop ra
+pop sp
+j ra
+push sp
+push ra
+l r1 d0 Vertical
+push r1
+l r2 d0 Horizontal
+push r2
+push 3
+jal 1
+move r3 r15
+push r3
+sub r0 sp 5
+get r15 db r0
+sub r0 sp 4
+get ra db r0
+j ra
+yield
+jal 8
+pop r0
+pop r9
+pop r8
+move sp r15
+jal 8
+pop r0
+pop r0
+pop r9
+move sp r15
+s db Setting r9
+j 23

rust_compiler/libs/integration_tests/src/test_files/reagent_processing.stlg

@@ -0,0 +1,49 @@
+device combustion = "d0";
+device furnace = "d1";
+device vent = "d2";
+device gasSensor = "d3";
+device self = "db";
+
+const MAX_WAIT_ITER = 2;
+const STACK_SIZE = 100;
+
+vent.Mode = 1; // Vent inward into pipes
+vent.On = false;
+let ejecting = false;
+let combustionWaitIter = 0;
+
+loop {
+  yield();
+
+  let reagentCount = combustion.Reagents;
+  
+  if (reagentCount >= STACK_SIZE || combustionWaitIter >= MAX_WAIT_ITER) {
+    ejecting = true;
+  }
+
+  combustionWaitIter = (reagentCount < STACK_SIZE && !ls(combustion, 0, "Occupied"))
+    ? combustionWaitIter + 1
+    : 0;
+
+  if (ejecting && combustion.Rpm < 1) {
+    combustion.Open = true;
+    ejecting = !(reagentCount == 0 && ls(combustion, 0, "Occupied"));
+  }
+
+  combustion.On = !ejecting;
+  
+  let furnaceAmt = ls(furnace, 0, "Quantity");
+
+  if (gasSensor.Pressure > 200) {
+    // safety: don't turn this on if we have gas still to process
+    // This should prevent pipes from blowing. This will NOT hault
+    // The in-progress burn job, but it'll prevent new jobs from
+    // blowing the walls or pipes.
+    continue;
+  } 
+
+  furnace.On = furnaceAmt > 0;
+  furnace.Activate = furnaceAmt > 0;
+  vent.On = gasSensor.Pressure > 0 || furnace.Activate;
+  self.Setting = furnace.Activate;
+}

rust_compiler/libs/integration_tests/src/test_files/test_larre_script.stlg

@@ -0,0 +1,72 @@
+/// Laree script V1
+
+device self = "db";
+device larre = "d0";
+device exportChute = "d1";
+
+const TOTAL_SLOTS = 19;
+const EXPORT_CHUTE = 1;
+const START_STATION = 2;
+
+let currentIndex = 0;
+
+/// Waits for the larre to be idle before continuing
+fn waitForIdle() {
+  yield();
+  while (!larre.Idle) {
+    yield();
+  }
+}
+
+/// Instructs the Larre to go to the chute and deposit
+/// what is currently in its arm
+fn deposit() {
+  larre.Setting = EXPORT_CHUTE;
+  waitForIdle();
+  larre.Activate = true;
+  waitForIdle();
+  exportChute.Open = false;
+}
+
+/// This function is responsible for checking the plant under
+/// the larre at this index, and harvesting if applicable
+fn checkAndHarvest(currentIndex) {
+  if (currentIndex <= EXPORT_CHUTE || ls(larre, 255, "Seeding") < 1) {
+    return;
+  }
+
+  // harvest from this device
+  while (ls(larre, 255, "Mature")) {
+    yield();
+    larre.Activate = true;
+  }
+  let hasRemainingPlant = ls(larre, 255, "Occupied");
+  
+  // move to the export chute
+  larre.Setting = EXPORT_CHUTE;
+  waitForIdle();
+  deposit();
+  if (hasRemainingPlant) {
+    deposit();
+  }
+
+  larre.Setting = currentIndex;
+  waitForIdle();
+
+  if (ls(larre, 0, "Occupied")) {
+    larre.Activate = true;
+  }
+  waitForIdle();
+}
+
+loop {
+  yield();
+  if (!larre.Idle) {
+    continue;
+  }
+  let newIndex = currentIndex + 1 > TOTAL_SLOTS ? START_STATION : currentIndex + 1;
+
+  checkAndHarvest(currentIndex);
+  larre.Setting = newIndex;
+  currentIndex = newIndex;
+}

rust_compiler/libs/optimizer/OPTIMIZATION_IDEAS.md

@@ -0,0 +1,212 @@
+# Additional Optimization Opportunities for Slang IL Optimizer
+
+## Currently Implemented ✓
+
+1. Constant Propagation - Folds math operations with known values
+2. Register Forwarding - Eliminates intermediate moves
+3. Function Call Optimization - Removes unnecessary push/pop around calls
+4. Leaf Function Optimization - Removes RA save/restore for non-calling functions
+5. Redundant Move Elimination - Removes `move rx rx`
+6. Dead Code Elimination - Removes unreachable code after jumps
+
+## Proposed Additional Optimizations
+
+### 1. **Algebraic Simplification** 🔥 HIGH IMPACT
+
+Simplify mathematical identities:
+
+- `x + 0` → `x` (move)
+- `x - 0` → `x` (move)
+- `x * 1` → `x` (move)
+- `x * 0` → `0` (move to constant)
+- `x / 1` → `x` (move)
+- `x - x` → `0` (move to constant)
+- `x % 1` → `0` (move to constant)
+
+**Example:**
+
+```
+add r1 r2 0     →    move r1 r2
+mul r3 r4 1     →    move r3 r4
+mul r5 r6 0     →    move r5 0
+```
+
+### 2. **Strength Reduction** 🔥 HIGH IMPACT
+
+Replace expensive operations with cheaper ones:
+
+- `x * 2` → `add x x x` (addition is cheaper than multiplication)
+- `x * power_of_2` → bit shifts (if IC10 supports)
+- `x / 2` → bit shifts (if IC10 supports)
+
+**Example:**
+
+```
+mul r1 r2 2     →    add r1 r2 r2
+```
+
+### 3. **Peephole Optimization - Instruction Sequences** 🔥 MEDIUM-HIGH IMPACT
+
+Recognize and optimize common instruction patterns:
+
+#### Pattern: Conditional Branch Simplification
+
+```
+seq r1 ra rb     →    beq ra rb label
+beqz r1 label         (remove the seq entirely)
+
+sne r1 ra rb     →    bne ra rb label
+beqz r1 label         (remove the sne entirely)
+```
+
+#### Pattern: Double Move Elimination
+
+```
+move r1 r2      →    move r1 r3
+move r1 r3          (remove first move if r1 not used between)
+```
+
+#### Pattern: Redundant Load Elimination
+
+If a register's value is already loaded and hasn't been clobbered:
+
+```
+l r1 d0 Temperature
+... (no writes to r1)
+l r1 d0 Temperature   →  (remove second load)
+```
+
+### 4. **Copy Propagation Enhancement** 🔥 MEDIUM IMPACT
+
+Current register forwarding is good, but we can extend it:
+
+- Track `move` chains: if `r1 = r2` and `r2 = 5`, propagate the `5` directly
+- Eliminate the intermediate register if possible
+
+### 5. **Dead Store Elimination** 🔥 MEDIUM IMPACT
+
+Remove writes to registers that are never read before being overwritten:
+
+```
+move r1 5
+move r1 10      →    move r1 10
+                     (first write is dead)
+```
+
+### 6. **Common Subexpression Elimination (CSE)** 🔥 MEDIUM-HIGH IMPACT
+
+Recognize when the same computation is done multiple times:
+
+```
+add r1 r8 r9
+add r2 r8 r9    →    add r1 r8 r9
+                     move r2 r1
+```
+
+This is especially valuable for expensive operations like:
+
+- Device loads (`l`)
+- Math functions (sqrt, sin, cos, etc.)
+
+### 7. **Jump Threading** 🔥 LOW-MEDIUM IMPACT
+
+Optimize jump-to-jump sequences:
+
+```
+j label1
+...
+label1:
+j label2        →    j label2 (rewrite first jump)
+```
+
+### 8. **Branch Folding** 🔥 LOW-MEDIUM IMPACT
+
+Merge consecutive branches to the same target:
+
+```
+bgt r1 r2 label
+bgt r3 r4 label  →   Could potentially be optimized based on conditions
+```
+
+### 9. **Loop Invariant Code Motion** 🔥 MEDIUM-HIGH IMPACT
+
+Move calculations out of loops if they don't change:
+
+```
+loop:
+  mul r2 5 10      →   mul r2 5 10      (hoisted before loop)
+  add r1 r1 r2         loop:
+  ...                    add r1 r1 r2
+  j loop                 ...
+                        j loop
+```
+
+### 10. **Select Instruction Optimization** 🔥 LOW-MEDIUM IMPACT
+
+The `select` instruction can sometimes replace branch patterns:
+
+```
+beq r1 r2 else
+move r3 r4
+j end
+else:
+move r3 r5        →   seq r6 r1 r2
+end:                   select r3 r6 r5 r4
+```
+
+### 11. **Stack Access Pattern Optimization** 🔥 LOW IMPACT
+
+If we see repeated `sub r0 sp N` + `get`, we might be able to optimize by:
+
+- Caching the stack address in a register if used multiple times
+- Combining sequential gets from adjacent stack slots
+
+### 12. **Inline Small Functions** 🔥 HIGH IMPACT (Complex to implement)
+
+For very small leaf functions (1-2 instructions), inline them at the call site:
+
+```
+calculateSum:
+  add r15 r8 r9
+  j ra
+
+main:
+  push 5           →   main:
+  push 10                add r15 5 10
+  jal calculateSum
+```
+
+### 13. **Branch Prediction Hints** 🔥 LOW IMPACT
+
+Reorganize code to put likely branches inline (fall-through) and unlikely branches as jumps.
+
+### 14. **Register Coalescing** 🔥 MEDIUM IMPACT
+
+Reduce register pressure by reusing registers that have non-overlapping lifetimes.
+
+## Priority Implementation Order
+
+### Phase 1 (Quick Wins):
+
+1. Algebraic Simplification (easy, high impact)
+2. Strength Reduction (easy, high impact)
+3. Dead Store Elimination (medium complexity, good impact)
+
+### Phase 2 (Medium Effort):
+
+4. Peephole Optimizations - seq/beq pattern (medium, high impact)
+5. Common Subexpression Elimination (medium, high impact)
+6. Copy Propagation Enhancement (medium, medium impact)
+
+### Phase 3 (Advanced):
+
+7. Loop Invariant Code Motion (complex, high impact for loop-heavy code)
+8. Function Inlining (complex, high impact)
+9. Register Coalescing (complex, medium impact)
+
+## Testing Strategy
+
+- Add test cases for each optimization
+- Ensure optimization preserves semantics (run existing tests after each)
+- Measure code size reduction
+- Consider adding benchmarks to measure game performance impact

rust_compiler/libs/optimizer/src/algebraic_simplification.rs

@@ -0,0 +1,161 @@
+use il::{Instruction, InstructionNode, Operand};
+use rust_decimal::Decimal;
+
+/// Pass: Algebraic Simplification
+/// Simplifies mathematical identities like x+0, x*1, x*0, etc.
+pub fn algebraic_simplification<'a>(
+    input: Vec<InstructionNode<'a>>,
+) -> (Vec<InstructionNode<'a>>, bool) {
+    let mut output = Vec::with_capacity(input.len());
+    let mut changed = false;
+
+    for mut node in input {
+        let simplified = match &node.instruction {
+            // x + 0 = x
+            Instruction::Add(dst, a, Operand::Number(n)) if n.is_zero() => {
+                Some(Instruction::Move(dst.clone(), a.clone()))
+            }
+            Instruction::Add(dst, Operand::Number(n), b) if n.is_zero() => {
+                Some(Instruction::Move(dst.clone(), b.clone()))
+            }
+
+            // x - 0 = x
+            Instruction::Sub(dst, a, Operand::Number(n)) if n.is_zero() => {
+                Some(Instruction::Move(dst.clone(), a.clone()))
+            }
+
+            // x * 1 = x
+            Instruction::Mul(dst, a, Operand::Number(n)) if *n == Decimal::from(1) => {
+                Some(Instruction::Move(dst.clone(), a.clone()))
+            }
+            Instruction::Mul(dst, Operand::Number(n), b) if *n == Decimal::from(1) => {
+                Some(Instruction::Move(dst.clone(), b.clone()))
+            }
+
+            // x * 0 = 0
+            Instruction::Mul(dst, _, Operand::Number(n)) if n.is_zero() => {
+                Some(Instruction::Move(dst.clone(), Operand::Number(Decimal::ZERO)))
+            }
+            Instruction::Mul(dst, Operand::Number(n), _) if n.is_zero() => {
+                Some(Instruction::Move(dst.clone(), Operand::Number(Decimal::ZERO)))
+            }
+
+            // x / 1 = x
+            Instruction::Div(dst, a, Operand::Number(n)) if *n == Decimal::from(1) => {
+                Some(Instruction::Move(dst.clone(), a.clone()))
+            }
+
+            // 0 / x = 0 (if x != 0, but we can't check at compile time for non-literals)
+            Instruction::Div(dst, Operand::Number(n), _) if n.is_zero() => {
+                Some(Instruction::Move(dst.clone(), Operand::Number(Decimal::ZERO)))
+            }
+
+            // x % 1 = 0
+            Instruction::Mod(dst, _, Operand::Number(n)) if *n == Decimal::from(1) => {
+                Some(Instruction::Move(dst.clone(), Operand::Number(Decimal::ZERO)))
+            }
+
+            // 0 % x = 0
+            Instruction::Mod(dst, Operand::Number(n), _) if n.is_zero() => {
+                Some(Instruction::Move(dst.clone(), Operand::Number(Decimal::ZERO)))
+            }
+
+            // x AND 0 = 0
+            Instruction::And(dst, _, Operand::Number(n)) if n.is_zero() => {
+                Some(Instruction::Move(dst.clone(), Operand::Number(Decimal::ZERO)))
+            }
+            Instruction::And(dst, Operand::Number(n), _) if n.is_zero() => {
+                Some(Instruction::Move(dst.clone(), Operand::Number(Decimal::ZERO)))
+            }
+
+            // x OR 0 = x
+            Instruction::Or(dst, a, Operand::Number(n)) if n.is_zero() => {
+                Some(Instruction::Move(dst.clone(), a.clone()))
+            }
+            Instruction::Or(dst, Operand::Number(n), b) if n.is_zero() => {
+                Some(Instruction::Move(dst.clone(), b.clone()))
+            }
+
+            // x XOR 0 = x
+            Instruction::Xor(dst, a, Operand::Number(n)) if n.is_zero() => {
+                Some(Instruction::Move(dst.clone(), a.clone()))
+            }
+            Instruction::Xor(dst, Operand::Number(n), b) if n.is_zero() => {
+                Some(Instruction::Move(dst.clone(), b.clone()))
+            }
+
+            _ => None,
+        };
+
+        if let Some(new) = simplified {
+            node.instruction = new;
+            changed = true;
+        }
+
+        output.push(node);
+    }
+
+    (output, changed)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_add_zero() {
+        let input = vec![InstructionNode::new(
+            Instruction::Add(
+                Operand::Register(1),
+                Operand::Register(2),
+                Operand::Number(Decimal::ZERO),
+            ),
+            None,
+        )];
+
+        let (output, changed) = algebraic_simplification(input);
+        assert!(changed);
+        assert!(matches!(
+            output[0].instruction,
+            Instruction::Move(Operand::Register(1), Operand::Register(2))
+        ));
+    }
+
+    #[test]
+    fn test_mul_one() {
+        let input = vec![InstructionNode::new(
+            Instruction::Mul(
+                Operand::Register(3),
+                Operand::Register(4),
+                Operand::Number(Decimal::ONE),
+            ),
+            None,
+        )];
+
+        let (output, changed) = algebraic_simplification(input);
+        assert!(changed);
+        assert!(matches!(
+            output[0].instruction,
+            Instruction::Move(Operand::Register(3), Operand::Register(4))
+        ));
+    }
+
+    #[test]
+    fn test_mul_zero() {
+        let input = vec![InstructionNode::new(
+            Instruction::Mul(
+                Operand::Register(5),
+                Operand::Register(6),
+                Operand::Number(Decimal::ZERO),
+            ),
+            None,
+        )];
+
+        let (output, changed) = algebraic_simplification(input);
+        assert!(changed);
+        assert!(matches!(
+            output[0].instruction,
+            Instruction::Move(Operand::Register(5), Operand::Number(_))
+        ));
+    }
+}

rust_compiler/libs/optimizer/src/constant_propagation.rs

@@ -0,0 +1,156 @@
+use crate::helpers::get_destination_reg;
+use il::{Instruction, InstructionNode, Operand};
+use rust_decimal::Decimal;
+
+/// Pass: Constant Propagation
+/// Folds arithmetic operations when both operands are constant.
+/// Also tracks register values and propagates them forward.
+pub fn constant_propagation<'a>(
+    input: Vec<InstructionNode<'a>>,
+) -> (Vec<InstructionNode<'a>>, bool) {
+    let mut output = Vec::with_capacity(input.len());
+    let mut changed = false;
+    let mut registers: [Option<Decimal>; 16] = [None; 16];
+
+    for mut node in input {
+        // Invalidate register tracking on label/call boundaries
+        match &node.instruction {
+            Instruction::LabelDef(_) | Instruction::JumpAndLink(_) => registers = [None; 16],
+            _ => {}
+        }
+
+        let simplified = match &node.instruction {
+            Instruction::Move(dst, src) => resolve_value(src, &registers)
+                .map(|val| Instruction::Move(dst.clone(), Operand::Number(val))),
+            Instruction::Add(dst, a, b) => try_fold_math(dst, a, b, &registers, |x, y| x + y),
+            Instruction::Sub(dst, a, b) => try_fold_math(dst, a, b, &registers, |x, y| x - y),
+            Instruction::Mul(dst, a, b) => try_fold_math(dst, a, b, &registers, |x, y| x * y),
+            Instruction::Div(dst, a, b) => try_fold_math(dst, a, b, &registers, |x, y| {
+                if y.is_zero() { Decimal::ZERO } else { x / y }
+            }),
+            Instruction::Mod(dst, a, b) => try_fold_math(dst, a, b, &registers, |x, y| {
+                if y.is_zero() { Decimal::ZERO } else { x % y }
+            }),
+            Instruction::BranchEq(a, b, l) => {
+                try_resolve_branch(a, b, l, &registers, |x, y| x == y)
+            }
+            Instruction::BranchNe(a, b, l) => {
+                try_resolve_branch(a, b, l, &registers, |x, y| x != y)
+            }
+            Instruction::BranchGt(a, b, l) => try_resolve_branch(a, b, l, &registers, |x, y| x > y),
+            Instruction::BranchLt(a, b, l) => try_resolve_branch(a, b, l, &registers, |x, y| x < y),
+            Instruction::BranchGe(a, b, l) => {
+                try_resolve_branch(a, b, l, &registers, |x, y| x >= y)
+            }
+            Instruction::BranchLe(a, b, l) => {
+                try_resolve_branch(a, b, l, &registers, |x, y| x <= y)
+            }
+            Instruction::BranchEqZero(a, l) => {
+                try_resolve_branch(a, &Operand::Number(0.into()), l, &registers, |x, y| x == y)
+            }
+            Instruction::BranchNeZero(a, l) => {
+                try_resolve_branch(a, &Operand::Number(0.into()), l, &registers, |x, y| x != y)
+            }
+            _ => None,
+        };
+
+        if let Some(new) = simplified {
+            node.instruction = new;
+            changed = true;
+        }
+
+        // Update register tracking
+        match &node.instruction {
+            Instruction::Move(Operand::Register(r), src) => {
+                registers[*r as usize] = resolve_value(src, &registers)
+            }
+            _ => {
+                if let Some(r) = get_destination_reg(&node.instruction) {
+                    registers[r as usize] = None;
+                }
+            }
+        }
+
+        // Filter out NOPs (empty labels from branch resolution)
+        if let Instruction::LabelDef(l) = &node.instruction
+            && l.is_empty()
+        {
+            changed = true;
+            continue;
+        }
+
+        output.push(node);
+    }
+    (output, changed)
+}
+
+fn resolve_value(op: &Operand, regs: &[Option<Decimal>; 16]) -> Option<Decimal> {
+    match op {
+        Operand::Number(n) => Some(*n),
+        Operand::Register(r) => regs[*r as usize],
+        _ => None,
+    }
+}
+
+fn try_fold_math<'a, F>(
+    dst: &Operand<'a>,
+    a: &Operand<'a>,
+    b: &Operand<'a>,
+    regs: &[Option<Decimal>; 16],
+    op: F,
+) -> Option<Instruction<'a>>
+where
+    F: Fn(Decimal, Decimal) -> Decimal,
+{
+    let val_a = resolve_value(a, regs)?;
+    let val_b = resolve_value(b, regs)?;
+    Some(Instruction::Move(
+        dst.clone(),
+        Operand::Number(op(val_a, val_b)),
+    ))
+}
+
+fn try_resolve_branch<'a, F>(
+    a: &Operand<'a>,
+    b: &Operand<'a>,
+    label: &Operand<'a>,
+    regs: &[Option<Decimal>; 16],
+    check: F,
+) -> Option<Instruction<'a>>
+where
+    F: Fn(Decimal, Decimal) -> bool,
+{
+    let val_a = resolve_value(a, regs)?;
+    let val_b = resolve_value(b, regs)?;
+    if check(val_a, val_b) {
+        Some(Instruction::Jump(label.clone()))
+    } else {
+        Some(Instruction::LabelDef("".into())) // NOP
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use il::InstructionNode;
+
+    #[test]
+    fn test_fold_add() {
+        let input = vec![InstructionNode::new(
+            Instruction::Add(
+                Operand::Register(1),
+                Operand::Number(5.into()),
+                Operand::Number(3.into()),
+            ),
+            None,
+        )];
+
+        let (output, changed) = constant_propagation(input);
+        assert!(changed);
+        assert_eq!(output.len(), 1);
+        assert!(matches!(
+            output[0].instruction,
+            Instruction::Move(Operand::Register(1), Operand::Number(_))
+        ));
+    }
+}

rust_compiler/libs/optimizer/src/dead_code.rs

@@ -0,0 +1,148 @@
+use il::{Instruction, InstructionNode, Operand};
+
+/// Pass: Redundant Move Elimination  
+/// Removes moves where source and destination are the same: `move rx rx`
+pub fn remove_redundant_moves<'a>(
+    input: Vec<InstructionNode<'a>>,
+) -> (Vec<InstructionNode<'a>>, bool) {
+    let mut output = Vec::with_capacity(input.len());
+    let mut changed = false;
+    for node in input {
+        if let Instruction::Move(dst, src) = &node.instruction
+            && dst == src
+        {
+            changed = true;
+            continue;
+        }
+        output.push(node);
+    }
+    (output, changed)
+}
+
+/// Pass: Dead Code Elimination
+/// Removes unreachable code after unconditional jumps.
+pub fn remove_unreachable_code<'a>(
+    input: Vec<InstructionNode<'a>>,
+) -> (Vec<InstructionNode<'a>>, bool) {
+    let mut output = Vec::with_capacity(input.len());
+    let mut changed = false;
+    let mut dead = false;
+    for node in input {
+        if let Instruction::LabelDef(_) = node.instruction {
+            dead = false;
+        }
+        if dead {
+            changed = true;
+            continue;
+        }
+        if let Instruction::Jump(_) = node.instruction {
+            dead = true
+        }
+        output.push(node);
+    }
+    (output, changed)
+}
+
+/// Pass: Remove Redundant Jumps
+/// Removes jumps to the next instruction (after label resolution).
+/// Must run AFTER label resolution since it needs line numbers.
+/// This pass also adjusts all jump targets to account for removed instructions.
+pub fn remove_redundant_jumps<'a>(
+    input: Vec<InstructionNode<'a>>,
+) -> (Vec<InstructionNode<'a>>, bool) {
+    let mut output = Vec::with_capacity(input.len());
+    let mut changed = false;
+    let mut removed_lines = Vec::new();
+
+    // First pass: identify redundant jumps
+    for (i, node) in input.iter().enumerate() {
+        // Check if this is a jump to the next line number
+        if let Instruction::Jump(Operand::Number(target)) = &node.instruction {
+            // Current line number is i, next line number is i+1
+            // If jump target equals the next line, it's redundant
+            if target.to_string().parse::<usize>().ok() == Some(i + 1) {
+                changed = true;
+                removed_lines.push(i);
+                continue; // Skip this redundant jump
+            }
+        }
+        output.push(node.clone());
+    }
+
+    // Second pass: adjust all jump/branch targets to account for removed lines
+    if changed {
+        for node in &mut output {
+            // Helper to adjust a target line number
+            let adjust_target = |target_line: usize| -> usize {
+                // Count how many removed lines are before the target
+                let offset = removed_lines
+                    .iter()
+                    .filter(|&&removed| removed < target_line)
+                    .count();
+                target_line.saturating_sub(offset)
+            };
+
+            match &mut node.instruction {
+                Instruction::Jump(Operand::Number(target))
+                | Instruction::JumpAndLink(Operand::Number(target)) => {
+                    if let Ok(target_line) = target.to_string().parse::<usize>() {
+                        *target = rust_decimal::Decimal::from(adjust_target(target_line));
+                    }
+                }
+                Instruction::BranchEq(_, _, Operand::Number(target))
+                | Instruction::BranchNe(_, _, Operand::Number(target))
+                | Instruction::BranchGt(_, _, Operand::Number(target))
+                | Instruction::BranchLt(_, _, Operand::Number(target))
+                | Instruction::BranchGe(_, _, Operand::Number(target))
+                | Instruction::BranchLe(_, _, Operand::Number(target))
+                | Instruction::BranchEqZero(_, Operand::Number(target))
+                | Instruction::BranchNeZero(_, Operand::Number(target)) => {
+                    if let Ok(target_line) = target.to_string().parse::<usize>() {
+                        *target = rust_decimal::Decimal::from(adjust_target(target_line));
+                    }
+                }
+                _ => {}
+            }
+        }
+    }
+
+    (output, changed)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use il::{Instruction, InstructionNode, Operand};
+
+    #[test]
+    fn test_remove_redundant_move() {
+        let input = vec![InstructionNode::new(
+            Instruction::Move(Operand::Register(1), Operand::Register(1)),
+            None,
+        )];
+
+        let (output, changed) = remove_redundant_moves(input);
+        assert!(changed);
+        assert_eq!(output.len(), 0);
+    }
+
+    #[test]
+    fn test_remove_unreachable() {
+        let input = vec![
+            InstructionNode::new(Instruction::Jump(Operand::Label("main".into())), None),
+            InstructionNode::new(
+                Instruction::Add(
+                    Operand::Register(1),
+                    Operand::Number(1.into()),
+                    Operand::Number(2.into()),
+                ),
+                None,
+            ),
+            InstructionNode::new(Instruction::LabelDef("main".into()), None),
+        ];
+
+        let (output, changed) = remove_unreachable_code(input);
+        assert!(changed);
+        assert_eq!(output.len(), 2);
+    }
+}

rust_compiler/libs/optimizer/src/dead_store_elimination.rs

@@ -0,0 +1,126 @@
+use crate::helpers::get_destination_reg;
+use il::{Instruction, InstructionNode};
+use std::collections::HashMap;
+
+/// Pass: Dead Store Elimination
+/// Removes writes to registers that are never read before being overwritten.
+pub fn dead_store_elimination<'a>(
+    input: Vec<InstructionNode<'a>>,
+) -> (Vec<InstructionNode<'a>>, bool) {
+    // Forward pass: Remove writes that are immediately overwritten
+    let (input, forward_changed) = eliminate_overwritten_stores(input);
+
+    // Note: Backward pass disabled for now - it needs more work to handle all cases correctly
+    // The forward pass is sufficient for most common patterns
+    // (e.g., move r6 r15 immediately followed by move r6 r15 again)
+
+    (input, forward_changed)
+}
+
+/// Forward pass: Remove stores that are overwritten before being read
+fn eliminate_overwritten_stores<'a>(
+    input: Vec<InstructionNode<'a>>,
+) -> (Vec<InstructionNode<'a>>, bool) {
+    let mut last_write: HashMap<u8, usize> = HashMap::new();
+    let mut to_remove = Vec::new();
+
+    // Scan for dead writes
+    for (i, node) in input.iter().enumerate() {
+        // Never remove Pop instructions - they have critical side effects on the stack pointer
+        if matches!(node.instruction, Instruction::Pop(_)) {
+            continue;
+        }
+
+        if let Some(dest_reg) = get_destination_reg(&node.instruction) {
+            // If this register was written before and hasn't been read, previous write is dead
+            if let Some(&prev_idx) = last_write.get(&dest_reg) {
+                // Check if the value was ever used between prev_idx and current
+                let was_used = input[prev_idx + 1..i]
+                    .iter()
+                    .any(|n| reg_is_read_or_affects_control(&n.instruction, dest_reg))
+                    // Also check if current instruction reads the register before overwriting it
+                    || reg_is_read_or_affects_control(&node.instruction, dest_reg);
+
+                if !was_used {
+                    // Previous write was dead
+                    to_remove.push(prev_idx);
+                }
+            }
+
+            // Update last write location
+            last_write.insert(dest_reg, i);
+        }
+
+        // Handle control flow instructions
+        match &node.instruction {
+            // JumpAndLink (function calls) only clobbers the return register (r15)
+            // We can continue tracking other registers across function calls
+            Instruction::JumpAndLink(_) => {
+                last_write.remove(&15);
+            }
+            // Other control flow instructions create complexity - clear all tracking
+            Instruction::Jump(_)
+            | Instruction::LabelDef(_)
+            | Instruction::BranchEq(_, _, _)
+            | Instruction::BranchNe(_, _, _)
+            | Instruction::BranchGt(_, _, _)
+            | Instruction::BranchLt(_, _, _)
+            | Instruction::BranchGe(_, _, _)
+            | Instruction::BranchLe(_, _, _)
+            | Instruction::BranchEqZero(_, _)
+            | Instruction::BranchNeZero(_, _) => {
+                last_write.clear();
+            }
+            _ => {}
+        }
+    }
+
+    if !to_remove.is_empty() {
+        let output = input
+            .into_iter()
+            .enumerate()
+            .filter_map(|(i, node)| {
+                if to_remove.contains(&i) {
+                    None
+                } else {
+                    Some(node)
+                }
+            })
+            .collect();
+        (output, true)
+    } else {
+        (input, false)
+    }
+}
+
+/// Simplified check: Does this instruction read the register?
+fn reg_is_read_or_affects_control(instr: &Instruction, reg: u8) -> bool {
+    use crate::helpers::reg_is_read;
+
+    // If it reads the register, it's used
+    reg_is_read(instr, reg)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use il::Operand;
+
+    #[test]
+    fn test_dead_store() {
+        let input = vec![
+            InstructionNode::new(
+                Instruction::Move(Operand::Register(1), Operand::Number(5.into())),
+                None,
+            ),
+            InstructionNode::new(
+                Instruction::Move(Operand::Register(1), Operand::Number(10.into())),
+                None,
+            ),
+        ];
+
+        let (output, changed) = dead_store_elimination(input);
+        assert!(changed);
+        assert_eq!(output.len(), 1);
+    }
+}

rust_compiler/libs/optimizer/src/function_call_optimization.rs

@@ -0,0 +1,160 @@
+use crate::helpers::get_destination_reg;
+use il::{Instruction, InstructionNode, Operand};
+use rust_decimal::Decimal;
+use std::collections::{HashMap, HashSet};
+
+/// Analyzes which registers are written to by each function label.
+fn analyze_clobbers(instructions: &[InstructionNode]) -> HashMap<String, HashSet<u8>> {
+    let mut clobbers = HashMap::new();
+    let mut current_label = None;
+
+    for node in instructions {
+        if let Instruction::LabelDef(label) = &node.instruction {
+            current_label = Some(label.to_string());
+            clobbers.insert(label.to_string(), HashSet::new());
+        }
+
+        if let Some(label) = &current_label
+            && let Some(reg) = get_destination_reg(&node.instruction)
+            && let Some(set) = clobbers.get_mut(label)
+        {
+            set.insert(reg);
+        }
+    }
+    clobbers
+}
+
+/// Pass: Function Call Optimization
+/// Removes Push/Restore pairs surrounding a JAL if the target function does not clobber that register.
+pub fn optimize_function_calls<'a>(
+    input: Vec<InstructionNode<'a>>,
+) -> (Vec<InstructionNode<'a>>, bool) {
+    let clobbers = analyze_clobbers(&input);
+    let mut changed = false;
+    let mut to_remove = HashSet::new();
+    let mut stack_adjustments = HashMap::new();
+
+    let mut i = 0;
+    while i < input.len() {
+        if let Instruction::JumpAndLink(Operand::Label(target)) = &input[i].instruction {
+            let target_key = target.to_string();
+
+            if let Some(func_clobbers) = clobbers.get(&target_key) {
+                // 1. Identify Pushes immediately preceding the JAL
+                let mut pushes = Vec::new(); // (index, register)
+                let mut scan_back = i.saturating_sub(1);
+                while scan_back > 0 {
+                    if to_remove.contains(&scan_back) {
+                        scan_back -= 1;
+                        continue;
+                    }
+                    if let Instruction::Push(Operand::Register(r)) = &input[scan_back].instruction {
+                        pushes.push((scan_back, *r));
+                        scan_back -= 1;
+                    } else {
+                        break;
+                    }
+                }
+
+                // 2. Identify Restores immediately following the JAL
+                let mut restores = Vec::new(); // (index_of_get, register, index_of_sub)
+                let mut scan_fwd = i + 1;
+                while scan_fwd < input.len() {
+                    // Skip 'sub r0 sp X'
+                    if let Instruction::Sub(Operand::Register(0), Operand::StackPointer, _) =
+                        &input[scan_fwd].instruction
+                    {
+                        // Check next instruction for the Get
+                        if scan_fwd + 1 < input.len()
+                            && let Instruction::Get(Operand::Register(r), _, Operand::Register(0)) =
+                                &input[scan_fwd + 1].instruction
+                        {
+                            restores.push((scan_fwd + 1, *r, scan_fwd));
+                            scan_fwd += 2;
+                            continue;
+                        }
+                    }
+                    break;
+                }
+
+                // 3. Stack Cleanup
+                let cleanup_idx = scan_fwd;
+                let has_cleanup = if cleanup_idx < input.len() {
+                    matches!(
+                        input[cleanup_idx].instruction,
+                        Instruction::Sub(
+                            Operand::StackPointer,
+                            Operand::StackPointer,
+                            Operand::Number(_)
+                        )
+                    )
+                } else {
+                    false
+                };
+
+                // SAFEGUARD: Check Counts!
+                let mut push_counts = HashMap::new();
+                for (_, r) in &pushes {
+                    *push_counts.entry(*r).or_insert(0) += 1;
+                }
+
+                let mut restore_counts = HashMap::new();
+                for (_, r, _) in &restores {
+                    *restore_counts.entry(*r).or_insert(0) += 1;
+                }
+
+                let counts_match = push_counts
+                    .iter()
+                    .all(|(reg, count)| restore_counts.get(reg).unwrap_or(&0) == count);
+                let counts_match_reverse = restore_counts
+                    .iter()
+                    .all(|(reg, count)| push_counts.get(reg).unwrap_or(&0) == count);
+
+                // Clobber Check
+                let all_pushes_safe = pushes.iter().all(|(_, r)| !func_clobbers.contains(r));
+
+                if all_pushes_safe && has_cleanup && counts_match && counts_match_reverse {
+                    // Remove all pushes/restores
+                    for (p_idx, _) in pushes {
+                        to_remove.insert(p_idx);
+                    }
+                    for (g_idx, _, s_idx) in restores {
+                        to_remove.insert(g_idx);
+                        to_remove.insert(s_idx);
+                    }
+
+                    // Reduce stack cleanup amount
+                    let num_removed = push_counts.values().sum::<i32>() as i64;
+                    stack_adjustments.insert(cleanup_idx, num_removed);
+                    changed = true;
+                }
+            }
+        }
+        i += 1;
+    }
+
+    if changed {
+        let mut clean = Vec::with_capacity(input.len());
+        for (idx, mut node) in input.into_iter().enumerate() {
+            if to_remove.contains(&idx) {
+                continue;
+            }
+
+            // Apply stack adjustment
+            if let Some(reduction) = stack_adjustments.get(&idx)
+                && let Instruction::Sub(dst, a, Operand::Number(n)) = &node.instruction
+            {
+                let new_n = n - Decimal::from(*reduction);
+                if new_n.is_zero() {
+                    continue;
+                }
+                node.instruction = Instruction::Sub(dst.clone(), a.clone(), Operand::Number(new_n));
+            }
+
+            clean.push(node);
+        }
+        return (clean, changed);
+    }
+
+    (input, false)
+}

rust_compiler/libs/optimizer/src/helpers.rs

@@ -0,0 +1,172 @@
+use il::{Instruction, Operand};
+
+/// Returns the register number written to by an instruction, if any.
+pub fn get_destination_reg(instr: &Instruction) -> Option<u8> {
+    match instr {
+        Instruction::Move(Operand::Register(r), _)
+        | Instruction::Add(Operand::Register(r), _, _)
+        | Instruction::Sub(Operand::Register(r), _, _)
+        | Instruction::Mul(Operand::Register(r), _, _)
+        | Instruction::Div(Operand::Register(r), _, _)
+        | Instruction::Mod(Operand::Register(r), _, _)
+        | Instruction::Pow(Operand::Register(r), _, _)
+        | Instruction::Load(Operand::Register(r), _, _)
+        | Instruction::LoadSlot(Operand::Register(r), _, _, _)
+        | Instruction::LoadBatch(Operand::Register(r), _, _, _)
+        | Instruction::LoadBatchNamed(Operand::Register(r), _, _, _, _)
+        | Instruction::SetEq(Operand::Register(r), _, _)
+        | Instruction::SetNe(Operand::Register(r), _, _)
+        | Instruction::SetGt(Operand::Register(r), _, _)
+        | Instruction::SetLt(Operand::Register(r), _, _)
+        | Instruction::SetGe(Operand::Register(r), _, _)
+        | Instruction::SetLe(Operand::Register(r), _, _)
+        | Instruction::And(Operand::Register(r), _, _)
+        | Instruction::Or(Operand::Register(r), _, _)
+        | Instruction::Xor(Operand::Register(r), _, _)
+        | Instruction::Peek(Operand::Register(r))
+        | Instruction::Get(Operand::Register(r), _, _)
+        | Instruction::Select(Operand::Register(r), _, _, _)
+        | Instruction::Rand(Operand::Register(r))
+        | Instruction::Acos(Operand::Register(r), _)
+        | Instruction::Asin(Operand::Register(r), _)
+        | Instruction::Atan(Operand::Register(r), _)
+        | Instruction::Atan2(Operand::Register(r), _, _)
+        | Instruction::Abs(Operand::Register(r), _)
+        | Instruction::Ceil(Operand::Register(r), _)
+        | Instruction::Cos(Operand::Register(r), _)
+        | Instruction::Floor(Operand::Register(r), _)
+        | Instruction::Log(Operand::Register(r), _)
+        | Instruction::Max(Operand::Register(r), _, _)
+        | Instruction::Min(Operand::Register(r), _, _)
+        | Instruction::Sin(Operand::Register(r), _)
+        | Instruction::Sqrt(Operand::Register(r), _)
+        | Instruction::Tan(Operand::Register(r), _)
+        | Instruction::Trunc(Operand::Register(r), _)
+        | Instruction::LoadReagent(Operand::Register(r), _, _, _)
+        | Instruction::Pop(Operand::Register(r)) => Some(*r),
+        _ => None,
+    }
+}
+
+/// Creates a new instruction with the destination register changed.
+pub fn set_destination_reg<'a>(instr: &Instruction<'a>, new_reg: u8) -> Option<Instruction<'a>> {
+    let r = Operand::Register(new_reg);
+    match instr {
+        Instruction::Move(_, b) => Some(Instruction::Move(r, b.clone())),
+        Instruction::Add(_, a, b) => Some(Instruction::Add(r, a.clone(), b.clone())),
+        Instruction::Sub(_, a, b) => Some(Instruction::Sub(r, a.clone(), b.clone())),
+        Instruction::Mul(_, a, b) => Some(Instruction::Mul(r, a.clone(), b.clone())),
+        Instruction::Div(_, a, b) => Some(Instruction::Div(r, a.clone(), b.clone())),
+        Instruction::Mod(_, a, b) => Some(Instruction::Mod(r, a.clone(), b.clone())),
+        Instruction::Pow(_, a, b) => Some(Instruction::Pow(r, a.clone(), b.clone())),
+        Instruction::Load(_, a, b) => Some(Instruction::Load(r, a.clone(), b.clone())),
+        Instruction::LoadSlot(_, a, b, c) => {
+            Some(Instruction::LoadSlot(r, a.clone(), b.clone(), c.clone()))
+        }
+        Instruction::LoadBatch(_, a, b, c) => {
+            Some(Instruction::LoadBatch(r, a.clone(), b.clone(), c.clone()))
+        }
+        Instruction::LoadBatchNamed(_, a, b, c, d) => Some(Instruction::LoadBatchNamed(
+            r,
+            a.clone(),
+            b.clone(),
+            c.clone(),
+            d.clone(),
+        )),
+        Instruction::LoadReagent(_, b, c, d) => {
+            Some(Instruction::LoadReagent(r, b.clone(), c.clone(), d.clone()))
+        }
+        Instruction::SetEq(_, a, b) => Some(Instruction::SetEq(r, a.clone(), b.clone())),
+        Instruction::SetNe(_, a, b) => Some(Instruction::SetNe(r, a.clone(), b.clone())),
+        Instruction::SetGt(_, a, b) => Some(Instruction::SetGt(r, a.clone(), b.clone())),
+        Instruction::SetLt(_, a, b) => Some(Instruction::SetLt(r, a.clone(), b.clone())),
+        Instruction::SetGe(_, a, b) => Some(Instruction::SetGe(r, a.clone(), b.clone())),
+        Instruction::SetLe(_, a, b) => Some(Instruction::SetLe(r, a.clone(), b.clone())),
+        Instruction::And(_, a, b) => Some(Instruction::And(r, a.clone(), b.clone())),
+        Instruction::Or(_, a, b) => Some(Instruction::Or(r, a.clone(), b.clone())),
+        Instruction::Xor(_, a, b) => Some(Instruction::Xor(r, a.clone(), b.clone())),
+        Instruction::Peek(_) => Some(Instruction::Peek(r)),
+        Instruction::Get(_, a, b) => Some(Instruction::Get(r, a.clone(), b.clone())),
+        Instruction::Select(_, a, b, c) => {
+            Some(Instruction::Select(r, a.clone(), b.clone(), c.clone()))
+        }
+        Instruction::Rand(_) => Some(Instruction::Rand(r)),
+        Instruction::Pop(_) => Some(Instruction::Pop(r)),
+        Instruction::Acos(_, a) => Some(Instruction::Acos(r, a.clone())),
+        Instruction::Asin(_, a) => Some(Instruction::Asin(r, a.clone())),
+        Instruction::Atan(_, a) => Some(Instruction::Atan(r, a.clone())),
+        Instruction::Atan2(_, a, b) => Some(Instruction::Atan2(r, a.clone(), b.clone())),
+        Instruction::Abs(_, a) => Some(Instruction::Abs(r, a.clone())),
+        Instruction::Ceil(_, a) => Some(Instruction::Ceil(r, a.clone())),
+        Instruction::Cos(_, a) => Some(Instruction::Cos(r, a.clone())),
+        Instruction::Floor(_, a) => Some(Instruction::Floor(r, a.clone())),
+        Instruction::Log(_, a) => Some(Instruction::Log(r, a.clone())),
+        Instruction::Max(_, a, b) => Some(Instruction::Max(r, a.clone(), b.clone())),
+        Instruction::Min(_, a, b) => Some(Instruction::Min(r, a.clone(), b.clone())),
+        Instruction::Sin(_, a) => Some(Instruction::Sin(r, a.clone())),
+        Instruction::Sqrt(_, a) => Some(Instruction::Sqrt(r, a.clone())),
+        Instruction::Tan(_, a) => Some(Instruction::Tan(r, a.clone())),
+        Instruction::Trunc(_, a) => Some(Instruction::Trunc(r, a.clone())),
+        _ => None,
+    }
+}
+
+/// Checks if a register is read by an instruction.
+pub fn reg_is_read(instr: &Instruction, reg: u8) -> bool {
+    let check = |op: &Operand| matches!(op, Operand::Register(r) if *r == reg);
+
+    match instr {
+        Instruction::Move(_, a) => check(a),
+        Instruction::Add(_, a, b)
+        | Instruction::Sub(_, a, b)
+        | Instruction::Mul(_, a, b)
+        | Instruction::Div(_, a, b)
+        | Instruction::Mod(_, a, b)
+        | Instruction::Pow(_, a, b) => check(a) || check(b),
+        Instruction::Load(_, a, _) => check(a),
+        Instruction::Store(a, _, b) => check(a) || check(b),
+        Instruction::BranchEq(a, b, _)
+        | Instruction::BranchNe(a, b, _)
+        | Instruction::BranchGt(a, b, _)
+        | Instruction::BranchLt(a, b, _)
+        | Instruction::BranchGe(a, b, _)
+        | Instruction::BranchLe(a, b, _) => check(a) || check(b),
+        Instruction::BranchEqZero(a, _) | Instruction::BranchNeZero(a, _) => check(a),
+        Instruction::LoadReagent(_, device, _, item_hash) => check(device) || check(item_hash),
+        Instruction::LoadSlot(_, dev, slot, _) => check(dev) || check(slot),
+        Instruction::LoadBatch(_, dev, _, mode) => check(dev) || check(mode),
+        Instruction::LoadBatchNamed(_, d_hash, n_hash, _, mode) => {
+            check(d_hash) || check(n_hash) || check(mode)
+        }
+        Instruction::SetEq(_, a, b)
+        | Instruction::SetNe(_, a, b)
+        | Instruction::SetGt(_, a, b)
+        | Instruction::SetLt(_, a, b)
+        | Instruction::SetGe(_, a, b)
+        | Instruction::SetLe(_, a, b)
+        | Instruction::And(_, a, b)
+        | Instruction::Or(_, a, b)
+        | Instruction::Xor(_, a, b) => check(a) || check(b),
+        Instruction::Push(a) => check(a),
+        Instruction::Get(_, a, b) => check(a) || check(b),
+        Instruction::Put(a, b, c) => check(a) || check(b) || check(c),
+        Instruction::Select(_, a, b, c) => check(a) || check(b) || check(c),
+        Instruction::Sleep(a) => check(a),
+        Instruction::Acos(_, a)
+        | Instruction::Asin(_, a)
+        | Instruction::Atan(_, a)
+        | Instruction::Abs(_, a)
+        | Instruction::Ceil(_, a)
+        | Instruction::Cos(_, a)
+        | Instruction::Floor(_, a)
+        | Instruction::Log(_, a)
+        | Instruction::Sin(_, a)
+        | Instruction::Sqrt(_, a)
+        | Instruction::Tan(_, a)
+        | Instruction::Trunc(_, a) => check(a),
+        Instruction::Atan2(_, a, b) | Instruction::Max(_, a, b) | Instruction::Min(_, a, b) => {
+            check(a) || check(b)
+        }
+        _ => false,
+    }
+}

rust_compiler/libs/optimizer/src/label_resolution.rs

@@ -0,0 +1,70 @@
+use il::{Instruction, InstructionNode, Operand};
+use rust_decimal::Decimal;
+use std::collections::HashMap;
+
+/// Pass: Resolve Labels
+/// Converts all Jump/Branch labels to absolute line numbers and removes LabelDefs.
+pub fn resolve_labels<'a>(input: Vec<InstructionNode<'a>>) -> Vec<InstructionNode<'a>> {
+    let mut label_map: HashMap<String, usize> = HashMap::new();
+    let mut line_number = 0;
+
+    // Build Label Map (filtering out LabelDefs from the count)
+    for node in &input {
+        if let Instruction::LabelDef(name) = &node.instruction {
+            label_map.insert(name.to_string(), line_number);
+        } else {
+            line_number += 1;
+        }
+    }
+
+    let mut output = Vec::with_capacity(input.len());
+
+    // Rewrite Jumps and Filter Labels
+    for mut node in input {
+        // Helper to get line number as Decimal operand
+        let get_line = |lbl: &Operand| -> Option<Operand<'a>> {
+            if let Operand::Label(name) = lbl {
+                label_map
+                    .get(name.as_ref())
+                    .map(|&l| Operand::Number(Decimal::from(l)))
+            } else {
+                None
+            }
+        };
+
+        match &mut node.instruction {
+            Instruction::LabelDef(_) => continue, // Strip labels
+
+            // Jumps
+            Instruction::Jump(op) => {
+                if let Some(num) = get_line(op) {
+                    *op = num;
+                }
+            }
+            Instruction::JumpAndLink(op) => {
+                if let Some(num) = get_line(op) {
+                    *op = num;
+                }
+            }
+            Instruction::BranchEq(_, _, op)
+            | Instruction::BranchNe(_, _, op)
+            | Instruction::BranchGt(_, _, op)
+            | Instruction::BranchLt(_, _, op)
+            | Instruction::BranchGe(_, _, op)
+            | Instruction::BranchLe(_, _, op) => {
+                if let Some(num) = get_line(op) {
+                    *op = num;
+                }
+            }
+            Instruction::BranchEqZero(_, op) | Instruction::BranchNeZero(_, op) => {
+                if let Some(num) = get_line(op) {
+                    *op = num;
+                }
+            }
+            _ => {}
+        }
+        output.push(node);
+    }
+
+    output
+}

rust_compiler/libs/optimizer/src/leaf_function_optimization.rs

@@ -0,0 +1,41 @@
+use crate::leaf_function::find_leaf_functions;
+use il::InstructionNode;
+
+/// Pass: Leaf Function Optimization
+/// If a function makes no calls (is a leaf), it doesn't need to save/restore `ra`.
+///
+/// NOTE: This optimization is DISABLED due to correctness issues.
+/// The optimization was designed for a specific calling convention (GET/PUT for RA)
+/// but the compiler generates POP ra for return address restoration. Without proper
+/// tracking of both conventions and validation of balanced push/pop pairs, this
+/// optimization corrupts the stack frame by:
+///
+/// 1. Removing `push ra` but not `pop ra`, leaving unbalanced push/pop pairs
+/// 2. Not accounting for parameter pops that occur before `push sp`
+/// 3. Assuming all RA restoration uses GET instruction, but code uses POP
+///
+/// Example of broken optimization:
+/// ```
+/// Unoptimized:          Optimized (BROKEN):
+/// compare:              pop r8
+/// pop r8                pop r9
+/// pop r9                ble r9 r8 5
+/// push sp               move r10 1
+/// push ra               j ra
+/// sgt r1 r9 r8          ^ Missing stack frame!
+/// ...
+/// pop ra
+/// pop sp
+/// j ra
+/// ```
+///
+/// Future work: Fix by handling both POP and GET calling conventions, validating
+/// balanced push/pop pairs, and accounting for parameter pops.
+pub fn optimize_leaf_functions<'a>(
+    input: Vec<InstructionNode<'a>>,
+) -> (Vec<InstructionNode<'a>>, bool) {
+    // Optimization disabled - returns input unchanged
+    #[allow(unused)]
+    let _leaves = find_leaf_functions(&input);
+    (input, false)
+}

rust_compiler/libs/optimizer/src/lib.rs

@@ -1,9 +1,30 @@
-use il::{Instruction, InstructionNode, Instructions, Operand};
+use il::Instructions;
-use rust_decimal::Decimal;
-use std::collections::{HashMap, HashSet};
 
+// Optimization pass modules
+mod helpers;
 mod leaf_function;
-use leaf_function::find_leaf_functions;
+
+mod algebraic_simplification;
+mod constant_propagation;
+mod dead_code;
+mod dead_store_elimination;
+mod function_call_optimization;
+mod label_resolution;
+mod leaf_function_optimization;
+mod peephole_optimization;
+mod register_forwarding;
+mod strength_reduction;
+
+use algebraic_simplification::algebraic_simplification;
+use constant_propagation::constant_propagation;
+use dead_code::{remove_redundant_jumps, remove_redundant_moves, remove_unreachable_code};
+use dead_store_elimination::dead_store_elimination;
+use function_call_optimization::optimize_function_calls;
+use label_resolution::resolve_labels;
+use leaf_function_optimization::optimize_leaf_functions;
+use peephole_optimization::peephole_optimization;
+use register_forwarding::register_forwarding;
+use strength_reduction::strength_reduction;
 
 /// Entry point for the optimizer.
 pub fn optimize<'a>(instructions: Instructions<'a>) -> Instructions<'a> {
@@ -38,845 +59,42 @@ pub fn optimize<'a>(instructions: Instructions<'a>) -> Instructions<'a> {
         instructions = new_inst;
         changed |= c4;
 
-        // Pass 5: Redundant Move Elimination
+        // Pass 5: Algebraic Simplification (Identity operations)
-        let (new_inst, c5) = remove_redundant_moves(instructions);
+        let (new_inst, c5) = algebraic_simplification(instructions);
         instructions = new_inst;
         changed |= c5;
 
-        // Pass 6: Dead Code Elimination
+        // Pass 6: Strength Reduction (Replace expensive ops with cheaper ones)
-        let (new_inst, c6) = remove_unreachable_code(instructions);
+        let (new_inst, c6) = strength_reduction(instructions);
         instructions = new_inst;
         changed |= c6;
+
+        // Pass 7: Peephole Optimizations (Common patterns)
+        let (new_inst, c7) = peephole_optimization(instructions);
+        instructions = new_inst;
+        changed |= c7;
+
+        // Pass 8: Dead Store Elimination
+        let (new_inst, c8) = dead_store_elimination(instructions);
+        instructions = new_inst;
+        changed |= c8;
+
+        // Pass 9: Redundant Move Elimination
+        let (new_inst, c9) = remove_redundant_moves(instructions);
+        instructions = new_inst;
+        changed |= c9;
+
+        // Pass 10: Dead Code Elimination
+        let (new_inst, c10) = remove_unreachable_code(instructions);
+        instructions = new_inst;
+        changed |= c10;
     }
 
     // Final Pass: Resolve Labels to Line Numbers
-    Instructions::new(resolve_labels(instructions))
+    let instructions = resolve_labels(instructions);
-}
+
-
+    // Post-resolution Pass: Remove redundant jumps (must run after label resolution)
-/// Helper: Check if a function body contains unsafe stack manipulation.
+    let (instructions, _) = remove_redundant_jumps(instructions);
-/// Returns true if the function modifies SP in a way that makes static RA offset analysis unsafe.
+
-fn function_has_complex_stack_ops(
+    Instructions::new(instructions)
-    instructions: &[InstructionNode],
-    start_idx: usize,
-    end_idx: usize,
-) -> bool {
-    for instruction in instructions.iter().take(end_idx).skip(start_idx) {
-        match instruction.instruction {
-            Instruction::Push(_) | Instruction::Pop(_) => return true,
-            // Check for explicit SP modification
-            Instruction::Add(Operand::StackPointer, _, _)
-            | Instruction::Sub(Operand::StackPointer, _, _)
-            | Instruction::Mul(Operand::StackPointer, _, _)
-            | Instruction::Div(Operand::StackPointer, _, _)
-            | Instruction::Move(Operand::StackPointer, _) => return true,
-            _ => {}
-        }
-    }
-    false
-}
-
-/// Pass: Leaf Function Optimization
-/// If a function makes no calls (is a leaf), it doesn't need to save/restore `ra`.
-fn optimize_leaf_functions<'a>(
-    input: Vec<InstructionNode<'a>>,
-) -> (Vec<InstructionNode<'a>>, bool) {
-    let leaves = find_leaf_functions(&input);
-    if leaves.is_empty() {
-        return (input, false);
-    }
-
-    let mut changed = false;
-    let mut to_remove = HashSet::new();
-
-    // We map function names to the INDEX of the instruction that restores RA.
-    // We use this to validate the function body later.
-    let mut func_restore_indices = HashMap::new();
-    let mut func_ra_offsets = HashMap::new();
-
-    let mut current_function: Option<String> = None;
-    let mut function_start_indices = HashMap::new();
-
-    // First scan: Identify instructions to remove and capture RA offsets
-    for (i, node) in input.iter().enumerate() {
-        match &node.instruction {
-            Instruction::LabelDef(label) if !label.starts_with("__internal_L") => {
-                current_function = Some(label.to_string());
-                function_start_indices.insert(label.to_string(), i);
-            }
-            Instruction::Push(Operand::ReturnAddress) => {
-                if let Some(func) = &current_function
-                    && leaves.contains(func)
-                {
-                    to_remove.insert(i);
-                }
-            }
-            Instruction::Get(Operand::ReturnAddress, _, Operand::Register(_)) => {
-                // This is the restore instruction: `get ra db r0`
-                if let Some(func) = &current_function
-                    && leaves.contains(func)
-                {
-                    to_remove.insert(i);
-                    func_restore_indices.insert(func.clone(), i);
-
-                    // Look back for the address calc: `sub r0 sp OFFSET`
-                    if i > 0
-                        && let Instruction::Sub(_, Operand::StackPointer, Operand::Number(n)) =
-                            &input[i - 1].instruction
-                    {
-                        func_ra_offsets.insert(func.clone(), *n);
-                        to_remove.insert(i - 1);
-                    }
-                }
-            }
-            _ => {}
-        }
-    }
-
-    // Safety Check: Verify that functions marked for optimization don't have complex stack ops.
-    // If they do, unmark them.
-    let mut safe_functions = HashSet::new();
-
-    for (func, start_idx) in &function_start_indices {
-        if let Some(restore_idx) = func_restore_indices.get(func) {
-            // Check instructions between start and restore using the helper function.
-            // We need to skip the `push ra` we just marked for removal, otherwise the helper
-            // will flag it as a complex op (Push).
-            // `start_idx` is the LabelDef. `start_idx + 1` is typically `push ra`.
-
-            let check_start = if to_remove.contains(&(start_idx + 1)) {
-                start_idx + 2
-            } else {
-                start_idx + 1
-            };
-
-            // `restore_idx` points to the `get ra` instruction. The helper scans up to `end_idx` exclusive,
-            // so we don't need to worry about the restore instruction itself.
-            if !function_has_complex_stack_ops(&input, check_start, *restore_idx) {
-                safe_functions.insert(func.clone());
-                changed = true;
-            }
-        }
-    }
-
-    if !changed {
-        return (input, false);
-    }
-
-    // Second scan: Rebuild with adjustments, but only for SAFE functions
-    let mut output = Vec::with_capacity(input.len());
-    let mut processing_function: Option<String> = None;
-
-    for (i, mut node) in input.into_iter().enumerate() {
-        if to_remove.contains(&i)
-            && let Some(func) = &processing_function
-            && safe_functions.contains(func)
-        {
-            continue; // SKIP (Remove)
-        }
-
-        if let Instruction::LabelDef(l) = &node.instruction
-            && !l.starts_with("__internal_L")
-        {
-            processing_function = Some(l.to_string());
-        }
-
-        // Apply Stack Adjustments
-        if let Some(func) = &processing_function
-            && safe_functions.contains(func)
-            && let Some(ra_offset) = func_ra_offsets.get(func)
-        {
-            // 1. Stack Cleanup Adjustment
-            if let Instruction::Sub(
-                Operand::StackPointer,
-                Operand::StackPointer,
-                Operand::Number(n),
-            ) = &mut node.instruction
-            {
-                // Decrease cleanup amount by 1 (for the removed RA)
-                let new_n = *n - Decimal::from(1);
-                if new_n.is_zero() {
-                    continue;
-                }
-                *n = new_n;
-            }
-
-            // 2. Stack Variable Offset Adjustment
-            // Since we verified the function is "Simple" (no nested stack mods),
-            // we can safely assume offsets > ra_offset need shifting.
-            if let Instruction::Sub(_, Operand::StackPointer, Operand::Number(n)) =
-                &mut node.instruction
-                && *n > *ra_offset
-            {
-                *n -= Decimal::from(1);
-            }
-        }
-
-        output.push(node);
-    }
-
-    (output, true)
-}
-
-/// Analyzes which registers are written to by each function label.
-fn analyze_clobbers(instructions: &[InstructionNode]) -> HashMap<String, HashSet<u8>> {
-    let mut clobbers = HashMap::new();
-    let mut current_label = None;
-
-    for node in instructions {
-        if let Instruction::LabelDef(label) = &node.instruction {
-            current_label = Some(label.to_string());
-            clobbers.insert(label.to_string(), HashSet::new());
-        }
-
-        if let Some(label) = &current_label
-            && let Some(reg) = get_destination_reg(&node.instruction)
-            && let Some(set) = clobbers.get_mut(label)
-        {
-            set.insert(reg);
-        }
-    }
-    clobbers
-}
-
-/// Pass: Function Call Optimization
-/// Removes Push/Restore pairs surrounding a JAL if the target function does not clobber that register.
-fn optimize_function_calls<'a>(
-    input: Vec<InstructionNode<'a>>,
-) -> (Vec<InstructionNode<'a>>, bool) {
-    let clobbers = analyze_clobbers(&input);
-    let mut changed = false;
-    let mut to_remove = HashSet::new();
-    let mut stack_adjustments = HashMap::new();
-
-    let mut i = 0;
-    while i < input.len() {
-        if let Instruction::JumpAndLink(Operand::Label(target)) = &input[i].instruction {
-            let target_key = target.to_string();
-
-            if let Some(func_clobbers) = clobbers.get(&target_key) {
-                // 1. Identify Pushes immediately preceding the JAL
-                let mut pushes = Vec::new(); // (index, register)
-                let mut scan_back = i.saturating_sub(1);
-                while scan_back > 0 {
-                    if to_remove.contains(&scan_back) {
-                        scan_back -= 1;
-                        continue;
-                    }
-                    if let Instruction::Push(Operand::Register(r)) = &input[scan_back].instruction {
-                        pushes.push((scan_back, *r));
-                        scan_back -= 1;
-                    } else {
-                        break;
-                    }
-                }
-
-                // 2. Identify Restores immediately following the JAL
-                let mut restores = Vec::new(); // (index_of_get, register, index_of_sub)
-                let mut scan_fwd = i + 1;
-                while scan_fwd < input.len() {
-                    // Skip 'sub r0 sp X'
-                    if let Instruction::Sub(Operand::Register(0), Operand::StackPointer, _) =
-                        &input[scan_fwd].instruction
-                    {
-                        // Check next instruction for the Get
-                        if scan_fwd + 1 < input.len()
-                            && let Instruction::Get(Operand::Register(r), _, Operand::Register(0)) =
-                                &input[scan_fwd + 1].instruction
-                        {
-                            restores.push((scan_fwd + 1, *r, scan_fwd));
-                            scan_fwd += 2;
-                            continue;
-                        }
-                    }
-                    break;
-                }
-
-                // 3. Stack Cleanup
-                let cleanup_idx = scan_fwd;
-                let has_cleanup = if cleanup_idx < input.len() {
-                    matches!(
-                        input[cleanup_idx].instruction,
-                        Instruction::Sub(
-                            Operand::StackPointer,
-                            Operand::StackPointer,
-                            Operand::Number(_)
-                        )
-                    )
-                } else {
-                    false
-                };
-
-                // SAFEGUARD: Check Counts!
-                // If we pushed r8 twice but only restored it once, we have an argument.
-                // We must ensure the number of pushes for each register MATCHES the number of restores.
-                let mut push_counts = HashMap::new();
-                for (_, r) in &pushes {
-                    *push_counts.entry(*r).or_insert(0) += 1;
-                }
-
-                let mut restore_counts = HashMap::new();
-                for (_, r, _) in &restores {
-                    *restore_counts.entry(*r).or_insert(0) += 1;
-                }
-
-                let counts_match = push_counts
-                    .iter()
-                    .all(|(reg, count)| restore_counts.get(reg).unwrap_or(&0) == count);
-                // Also check reverse to ensure we didn't restore something we didn't push (unlikely but possible)
-                let counts_match_reverse = restore_counts
-                    .iter()
-                    .all(|(reg, count)| push_counts.get(reg).unwrap_or(&0) == count);
-
-                // Clobber Check
-                let all_pushes_safe = pushes.iter().all(|(_, r)| !func_clobbers.contains(r));
-
-                if all_pushes_safe && has_cleanup && counts_match && counts_match_reverse {
-                    // We can remove ALL found pushes/restores safely
-                    for (p_idx, _) in pushes {
-                        to_remove.insert(p_idx);
-                    }
-                    for (g_idx, _, s_idx) in restores {
-                        to_remove.insert(g_idx);
-                        to_remove.insert(s_idx);
-                    }
-
-                    // Reduce stack cleanup amount
-                    let num_removed = push_counts.values().sum::<i32>() as i64;
-                    stack_adjustments.insert(cleanup_idx, num_removed);
-                    changed = true;
-                }
-            }
-        }
-        i += 1;
-    }
-
-    if changed {
-        let mut clean = Vec::with_capacity(input.len());
-        for (idx, mut node) in input.into_iter().enumerate() {
-            if to_remove.contains(&idx) {
-                continue;
-            }
-
-            // Apply stack adjustment
-            if let Some(reduction) = stack_adjustments.get(&idx)
-                && let Instruction::Sub(dst, a, Operand::Number(n)) = &node.instruction
-            {
-                let new_n = n - Decimal::from(*reduction);
-                if new_n.is_zero() {
-                    continue; // Remove the sub entirely if 0
-                }
-                node.instruction = Instruction::Sub(dst.clone(), a.clone(), Operand::Number(new_n));
-            }
-
-            clean.push(node);
-        }
-        return (clean, changed);
-    }
-
-    (input, false)
-}
-
-/// Pass: Register Forwarding
-/// Eliminates intermediate moves by writing directly to the final destination.
-/// Example: `l r1 d0 T` + `move r9 r1` -> `l r9 d0 T`
-fn register_forwarding<'a>(
-    mut input: Vec<InstructionNode<'a>>,
-) -> (Vec<InstructionNode<'a>>, bool) {
-    let mut changed = false;
-    let mut i = 0;
-
-    // We use a while loop to manually control index so we can peek ahead
-    while i < input.len().saturating_sub(1) {
-        let next_idx = i + 1;
-
-        // Check if current instruction defines a register
-        // and the NEXT instruction is a move from that register.
-        let forward_candidate = if let Some(def_reg) = get_destination_reg(&input[i].instruction) {
-            if let Instruction::Move(Operand::Register(dest_reg), Operand::Register(src_reg)) =
-                &input[next_idx].instruction
-            {
-                if *src_reg == def_reg {
-                    // Candidate found: Instruction `i` defines `src_reg`, Instruction `i+1` moves `src_reg` to `dest_reg`.
-                    // We can optimize if `src_reg` (the temp) is NOT used after this move.
-                    Some((def_reg, *dest_reg))
-                } else {
-                    None
-                }
-            } else {
-                None
-            }
-        } else {
-            None
-        };
-
-        if let Some((temp_reg, final_reg)) = forward_candidate {
-            // Check liveness: Is temp_reg used after i+1?
-            // We scan from i+2 onwards.
-            let mut temp_is_dead = true;
-            for node in input.iter().skip(i + 2) {
-                if reg_is_read(&node.instruction, temp_reg) {
-                    temp_is_dead = false;
-                    break;
-                }
-                // If the temp is redefined, then the old value is dead, so we are safe.
-                if let Some(redef) = get_destination_reg(&node.instruction)
-                    && redef == temp_reg
-                {
-                    break;
-                }
-
-                // If we hit a label/jump, we assume liveness might leak (conservative safety)
-                if matches!(
-                    node.instruction,
-                    Instruction::LabelDef(_) | Instruction::Jump(_) | Instruction::JumpAndLink(_)
-                ) {
-                    temp_is_dead = false;
-                    break;
-                }
-            }
-
-            if temp_is_dead {
-                // Perform the swap
-                // 1. Rewrite input[i] to write to final_reg
-                if let Some(new_instr) = set_destination_reg(&input[i].instruction, final_reg) {
-                    input[i].instruction = new_instr;
-                    // 2. Remove input[i+1] (The Move)
-                    input.remove(next_idx);
-                    changed = true;
-                    // Don't increment i, re-evaluate current index (which is now a new neighbor)
-                    continue;
-                }
-            }
-        }
-
-        i += 1;
-    }
-
-    (input, changed)
-}
-
-/// Pass: Resolve Labels
-/// Converts all Jump/Branch labels to absolute line numbers and removes LabelDefs.
-fn resolve_labels<'a>(input: Vec<InstructionNode<'a>>) -> Vec<InstructionNode<'a>> {
-    let mut label_map: HashMap<String, usize> = HashMap::new();
-    let mut line_number = 0;
-
-    // 1. Build Label Map (filtering out LabelDefs from the count)
-    for node in &input {
-        if let Instruction::LabelDef(name) = &node.instruction {
-            label_map.insert(name.to_string(), line_number);
-        } else {
-            line_number += 1;
-        }
-    }
-
-    let mut output = Vec::with_capacity(input.len());
-
-    // 2. Rewrite Jumps and Filter Labels
-    for mut node in input {
-        // Helper to get line number as Decimal operand
-        let get_line = |lbl: &Operand| -> Option<Operand<'a>> {
-            if let Operand::Label(name) = lbl {
-                label_map
-                    .get(name.as_ref())
-                    .map(|&l| Operand::Number(Decimal::from(l)))
-            } else {
-                None
-            }
-        };
-
-        match &mut node.instruction {
-            Instruction::LabelDef(_) => continue, // Strip labels
-
-            // Jumps
-            Instruction::Jump(op) => {
-                if let Some(num) = get_line(op) {
-                    *op = num;
-                }
-            }
-            Instruction::JumpAndLink(op) => {
-                if let Some(num) = get_line(op) {
-                    *op = num;
-                }
-            }
-            Instruction::BranchEq(_, _, op)
-            | Instruction::BranchNe(_, _, op)
-            | Instruction::BranchGt(_, _, op)
-            | Instruction::BranchLt(_, _, op)
-            | Instruction::BranchGe(_, _, op)
-            | Instruction::BranchLe(_, _, op) => {
-                if let Some(num) = get_line(op) {
-                    *op = num;
-                }
-            }
-            Instruction::BranchEqZero(_, op) | Instruction::BranchNeZero(_, op) => {
-                if let Some(num) = get_line(op) {
-                    *op = num;
-                }
-            }
-            _ => {}
-        }
-        output.push(node);
-    }
-
-    output
-}
-
-// --- Helpers for Register Analysis ---
-
-fn get_destination_reg(instr: &Instruction) -> Option<u8> {
-    match instr {
-        Instruction::Move(Operand::Register(r), _)
-        | Instruction::Add(Operand::Register(r), _, _)
-        | Instruction::Sub(Operand::Register(r), _, _)
-        | Instruction::Mul(Operand::Register(r), _, _)
-        | Instruction::Div(Operand::Register(r), _, _)
-        | Instruction::Mod(Operand::Register(r), _, _)
-        | Instruction::Pow(Operand::Register(r), _, _)
-        | Instruction::Load(Operand::Register(r), _, _)
-        | Instruction::LoadSlot(Operand::Register(r), _, _, _)
-        | Instruction::LoadBatch(Operand::Register(r), _, _, _)
-        | Instruction::LoadBatchNamed(Operand::Register(r), _, _, _, _)
-        | Instruction::SetEq(Operand::Register(r), _, _)
-        | Instruction::SetNe(Operand::Register(r), _, _)
-        | Instruction::SetGt(Operand::Register(r), _, _)
-        | Instruction::SetLt(Operand::Register(r), _, _)
-        | Instruction::SetGe(Operand::Register(r), _, _)
-        | Instruction::SetLe(Operand::Register(r), _, _)
-        | Instruction::And(Operand::Register(r), _, _)
-        | Instruction::Or(Operand::Register(r), _, _)
-        | Instruction::Xor(Operand::Register(r), _, _)
-        | Instruction::Peek(Operand::Register(r))
-        | Instruction::Get(Operand::Register(r), _, _)
-        | Instruction::Select(Operand::Register(r), _, _, _)
-        | Instruction::Rand(Operand::Register(r))
-        | Instruction::Acos(Operand::Register(r), _)
-        | Instruction::Asin(Operand::Register(r), _)
-        | Instruction::Atan(Operand::Register(r), _)
-        | Instruction::Atan2(Operand::Register(r), _, _)
-        | Instruction::Abs(Operand::Register(r), _)
-        | Instruction::Ceil(Operand::Register(r), _)
-        | Instruction::Cos(Operand::Register(r), _)
-        | Instruction::Floor(Operand::Register(r), _)
-        | Instruction::Log(Operand::Register(r), _)
-        | Instruction::Max(Operand::Register(r), _, _)
-        | Instruction::Min(Operand::Register(r), _, _)
-        | Instruction::Sin(Operand::Register(r), _)
-        | Instruction::Sqrt(Operand::Register(r), _)
-        | Instruction::Tan(Operand::Register(r), _)
-        | Instruction::Trunc(Operand::Register(r), _)
-        | Instruction::LoadReagent(Operand::Register(r), _, _, _)
-        | Instruction::Pop(Operand::Register(r)) => Some(*r),
-        _ => None,
-    }
-}
-
-fn set_destination_reg<'a>(instr: &Instruction<'a>, new_reg: u8) -> Option<Instruction<'a>> {
-    // Helper to easily recreate instruction with new dest
-    let r = Operand::Register(new_reg);
-    match instr {
-        Instruction::Move(_, b) => Some(Instruction::Move(r, b.clone())),
-        Instruction::Add(_, a, b) => Some(Instruction::Add(r, a.clone(), b.clone())),
-        Instruction::Sub(_, a, b) => Some(Instruction::Sub(r, a.clone(), b.clone())),
-        Instruction::Mul(_, a, b) => Some(Instruction::Mul(r, a.clone(), b.clone())),
-        Instruction::Div(_, a, b) => Some(Instruction::Div(r, a.clone(), b.clone())),
-        Instruction::Mod(_, a, b) => Some(Instruction::Mod(r, a.clone(), b.clone())),
-        Instruction::Pow(_, a, b) => Some(Instruction::Pow(r, a.clone(), b.clone())),
-        Instruction::Load(_, a, b) => Some(Instruction::Load(r, a.clone(), b.clone())),
-        Instruction::LoadSlot(_, a, b, c) => {
-            Some(Instruction::LoadSlot(r, a.clone(), b.clone(), c.clone()))
-        }
-        Instruction::LoadBatch(_, a, b, c) => {
-            Some(Instruction::LoadBatch(r, a.clone(), b.clone(), c.clone()))
-        }
-        Instruction::LoadBatchNamed(_, a, b, c, d) => Some(Instruction::LoadBatchNamed(
-            r,
-            a.clone(),
-            b.clone(),
-            c.clone(),
-            d.clone(),
-        )),
-        Instruction::LoadReagent(_, b, c, d) => {
-            Some(Instruction::LoadReagent(r, b.clone(), c.clone(), d.clone()))
-        }
-        Instruction::SetEq(_, a, b) => Some(Instruction::SetEq(r, a.clone(), b.clone())),
-        Instruction::SetNe(_, a, b) => Some(Instruction::SetNe(r, a.clone(), b.clone())),
-        Instruction::SetGt(_, a, b) => Some(Instruction::SetGt(r, a.clone(), b.clone())),
-        Instruction::SetLt(_, a, b) => Some(Instruction::SetLt(r, a.clone(), b.clone())),
-        Instruction::SetGe(_, a, b) => Some(Instruction::SetGe(r, a.clone(), b.clone())),
-        Instruction::SetLe(_, a, b) => Some(Instruction::SetLe(r, a.clone(), b.clone())),
-        Instruction::And(_, a, b) => Some(Instruction::And(r, a.clone(), b.clone())),
-        Instruction::Or(_, a, b) => Some(Instruction::Or(r, a.clone(), b.clone())),
-        Instruction::Xor(_, a, b) => Some(Instruction::Xor(r, a.clone(), b.clone())),
-        Instruction::Peek(_) => Some(Instruction::Peek(r)),
-        Instruction::Get(_, a, b) => Some(Instruction::Get(r, a.clone(), b.clone())),
-        Instruction::Select(_, a, b, c) => {
-            Some(Instruction::Select(r, a.clone(), b.clone(), c.clone()))
-        }
-        Instruction::Rand(_) => Some(Instruction::Rand(r)),
-        Instruction::Pop(_) => Some(Instruction::Pop(r)),
-
-        // Math funcs
-        Instruction::Acos(_, a) => Some(Instruction::Acos(r, a.clone())),
-        Instruction::Asin(_, a) => Some(Instruction::Asin(r, a.clone())),
-        Instruction::Atan(_, a) => Some(Instruction::Atan(r, a.clone())),
-        Instruction::Atan2(_, a, b) => Some(Instruction::Atan2(r, a.clone(), b.clone())),
-        Instruction::Abs(_, a) => Some(Instruction::Abs(r, a.clone())),
-        Instruction::Ceil(_, a) => Some(Instruction::Ceil(r, a.clone())),
-        Instruction::Cos(_, a) => Some(Instruction::Cos(r, a.clone())),
-        Instruction::Floor(_, a) => Some(Instruction::Floor(r, a.clone())),
-        Instruction::Log(_, a) => Some(Instruction::Log(r, a.clone())),
-        Instruction::Max(_, a, b) => Some(Instruction::Max(r, a.clone(), b.clone())),
-        Instruction::Min(_, a, b) => Some(Instruction::Min(r, a.clone(), b.clone())),
-        Instruction::Sin(_, a) => Some(Instruction::Sin(r, a.clone())),
-        Instruction::Sqrt(_, a) => Some(Instruction::Sqrt(r, a.clone())),
-        Instruction::Tan(_, a) => Some(Instruction::Tan(r, a.clone())),
-        Instruction::Trunc(_, a) => Some(Instruction::Trunc(r, a.clone())),
-
-        _ => None,
-    }
-}
-
-fn reg_is_read(instr: &Instruction, reg: u8) -> bool {
-    let check = |op: &Operand| matches!(op, Operand::Register(r) if *r == reg);
-
-    match instr {
-        Instruction::Move(_, a) => check(a),
-        Instruction::Add(_, a, b)
-        | Instruction::Sub(_, a, b)
-        | Instruction::Mul(_, a, b)
-        | Instruction::Div(_, a, b)
-        | Instruction::Mod(_, a, b)
-        | Instruction::Pow(_, a, b) => check(a) || check(b),
-
-        Instruction::Load(_, a, _) => check(a), // Load reads device? Device can be reg? Yes.
-        Instruction::Store(a, _, b) => check(a) || check(b),
-
-        Instruction::BranchEq(a, b, _)
-        | Instruction::BranchNe(a, b, _)
-        | Instruction::BranchGt(a, b, _)
-        | Instruction::BranchLt(a, b, _)
-        | Instruction::BranchGe(a, b, _)
-        | Instruction::BranchLe(a, b, _) => check(a) || check(b),
-
-        Instruction::BranchEqZero(a, _) | Instruction::BranchNeZero(a, _) => check(a),
-
-        Instruction::LoadReagent(_, device, _, item_hash) => check(device) || check(item_hash),
-
-        Instruction::LoadSlot(_, dev, slot, _) => check(dev) || check(slot),
-        Instruction::LoadBatch(_, dev, _, mode) => check(dev) || check(mode),
-        Instruction::LoadBatchNamed(_, d_hash, n_hash, _, mode) => {
-            check(d_hash) || check(n_hash) || check(mode)
-        }
-
-        Instruction::SetEq(_, a, b)
-        | Instruction::SetNe(_, a, b)
-        | Instruction::SetGt(_, a, b)
-        | Instruction::SetLt(_, a, b)
-        | Instruction::SetGe(_, a, b)
-        | Instruction::SetLe(_, a, b)
-        | Instruction::And(_, a, b)
-        | Instruction::Or(_, a, b)
-        | Instruction::Xor(_, a, b) => check(a) || check(b),
-
-        Instruction::Push(a) => check(a),
-        Instruction::Get(_, a, b) => check(a) || check(b),
-        Instruction::Put(a, b, c) => check(a) || check(b) || check(c),
-
-        Instruction::Select(_, a, b, c) => check(a) || check(b) || check(c),
-        Instruction::Sleep(a) => check(a),
-
-        // Math single arg
-        Instruction::Acos(_, a)
-        | Instruction::Asin(_, a)
-        | Instruction::Atan(_, a)
-        | Instruction::Abs(_, a)
-        | Instruction::Ceil(_, a)
-        | Instruction::Cos(_, a)
-        | Instruction::Floor(_, a)
-        | Instruction::Log(_, a)
-        | Instruction::Sin(_, a)
-        | Instruction::Sqrt(_, a)
-        | Instruction::Tan(_, a)
-        | Instruction::Trunc(_, a) => check(a),
-
-        // Math double arg
-        Instruction::Atan2(_, a, b) | Instruction::Max(_, a, b) | Instruction::Min(_, a, b) => {
-            check(a) || check(b)
-        }
-
-        _ => false,
-    }
-}
-
-/// --- Constant Propagation & Dead Code ---
-fn constant_propagation<'a>(input: Vec<InstructionNode<'a>>) -> (Vec<InstructionNode<'a>>, bool) {
-    let mut output = Vec::with_capacity(input.len());
-    let mut changed = false;
-    let mut registers: [Option<Decimal>; 16] = [None; 16];
-
-    for mut node in input {
-        match &node.instruction {
-            Instruction::LabelDef(_) | Instruction::JumpAndLink(_) => registers = [None; 16],
-            _ => {}
-        }
-
-        let simplified = match &node.instruction {
-            Instruction::Move(dst, src) => resolve_value(src, &registers)
-                .map(|val| Instruction::Move(dst.clone(), Operand::Number(val))),
-            Instruction::Add(dst, a, b) => try_fold_math(dst, a, b, &registers, |x, y| x + y),
-            Instruction::Sub(dst, a, b) => try_fold_math(dst, a, b, &registers, |x, y| x - y),
-            Instruction::Mul(dst, a, b) => try_fold_math(dst, a, b, &registers, |x, y| x * y),
-            Instruction::Div(dst, a, b) => {
-                try_fold_math(
-                    dst,
-                    a,
-                    b,
-                    &registers,
-                    |x, y| if y.is_zero() { x } else { x / y },
-                )
-            }
-            Instruction::Mod(dst, a, b) => {
-                try_fold_math(
-                    dst,
-                    a,
-                    b,
-                    &registers,
-                    |x, y| if y.is_zero() { x } else { x % y },
-                )
-            }
-            Instruction::BranchEq(a, b, l) => {
-                try_resolve_branch(a, b, l, &registers, |x, y| x == y)
-            }
-            Instruction::BranchNe(a, b, l) => {
-                try_resolve_branch(a, b, l, &registers, |x, y| x != y)
-            }
-            Instruction::BranchGt(a, b, l) => try_resolve_branch(a, b, l, &registers, |x, y| x > y),
-            Instruction::BranchLt(a, b, l) => try_resolve_branch(a, b, l, &registers, |x, y| x < y),
-            Instruction::BranchGe(a, b, l) => {
-                try_resolve_branch(a, b, l, &registers, |x, y| x >= y)
-            }
-            Instruction::BranchLe(a, b, l) => {
-                try_resolve_branch(a, b, l, &registers, |x, y| x <= y)
-            }
-            Instruction::BranchEqZero(a, l) => {
-                try_resolve_branch(a, &Operand::Number(0.into()), l, &registers, |x, y| x == y)
-            }
-            Instruction::BranchNeZero(a, l) => {
-                try_resolve_branch(a, &Operand::Number(0.into()), l, &registers, |x, y| x != y)
-            }
-            _ => None,
-        };
-
-        if let Some(new) = simplified {
-            node.instruction = new;
-            changed = true;
-        }
-
-        // Update tracking
-        match &node.instruction {
-            Instruction::Move(Operand::Register(r), src) => {
-                registers[*r as usize] = resolve_value(src, &registers)
-            }
-            // Invalidate if destination is register
-            _ => {
-                if let Some(r) = get_destination_reg(&node.instruction) {
-                    registers[r as usize] = None;
-                }
-            }
-        }
-
-        // Filter out NOPs (Empty LabelDefs from branch resolution)
-        if let Instruction::LabelDef(l) = &node.instruction
-            && l.is_empty()
-        {
-            changed = true;
-            continue;
-        }
-
-        output.push(node);
-    }
-    (output, changed)
-}
-
-fn resolve_value(op: &Operand, regs: &[Option<Decimal>; 16]) -> Option<Decimal> {
-    match op {
-        Operand::Number(n) => Some(*n),
-        Operand::Register(r) => regs[*r as usize],
-        _ => None,
-    }
-}
-
-fn try_fold_math<'a, F>(
-    dst: &Operand<'a>,
-    a: &Operand<'a>,
-    b: &Operand<'a>,
-    regs: &[Option<Decimal>; 16],
-    op: F,
-) -> Option<Instruction<'a>>
-where
-    F: Fn(Decimal, Decimal) -> Decimal,
-{
-    let val_a = resolve_value(a, regs)?;
-    let val_b = resolve_value(b, regs)?;
-    Some(Instruction::Move(
-        dst.clone(),
-        Operand::Number(op(val_a, val_b)),
-    ))
-}
-
-fn try_resolve_branch<'a, F>(
-    a: &Operand<'a>,
-    b: &Operand<'a>,
-    label: &Operand<'a>,
-    regs: &[Option<Decimal>; 16],
-    check: F,
-) -> Option<Instruction<'a>>
-where
-    F: Fn(Decimal, Decimal) -> bool,
-{
-    let val_a = resolve_value(a, regs)?;
-    let val_b = resolve_value(b, regs)?;
-    if check(val_a, val_b) {
-        Some(Instruction::Jump(label.clone()))
-    } else {
-        Some(Instruction::LabelDef("".into())) // NOP
-    }
-}
-
-fn remove_redundant_moves<'a>(input: Vec<InstructionNode<'a>>) -> (Vec<InstructionNode<'a>>, bool) {
-    let mut output = Vec::with_capacity(input.len());
-    let mut changed = false;
-    for node in input {
-        if let Instruction::Move(dst, src) = &node.instruction
-            && dst == src
-        {
-            changed = true;
-            continue;
-        }
-        output.push(node);
-    }
-    (output, changed)
-}
-
-fn remove_unreachable_code<'a>(
-    input: Vec<InstructionNode<'a>>,
-) -> (Vec<InstructionNode<'a>>, bool) {
-    let mut output = Vec::with_capacity(input.len());
-    let mut changed = false;
-    let mut dead = false;
-    for node in input {
-        if let Instruction::LabelDef(_) = node.instruction {
-            dead = false;
-        }
-        if dead {
-            changed = true;
-            continue;
-        }
-        if let Instruction::Jump(_) = node.instruction {
-            dead = true
-        }
-        output.push(node);
-    }
-    (output, changed)
 }

rust_compiler/libs/optimizer/src/peephole_optimization.rs

@@ -0,0 +1,761 @@
+use il::{Instruction, InstructionNode, Operand};
+
+/// Pass: Peephole Optimization
+/// Recognizes and optimizes common instruction patterns.
+pub fn peephole_optimization<'a>(
+    input: Vec<InstructionNode<'a>>,
+) -> (Vec<InstructionNode<'a>>, bool) {
+    let mut output = Vec::with_capacity(input.len());
+    let mut changed = false;
+    let mut i = 0;
+
+    while i < input.len() {
+        // Pattern: push sp; push ra ... pop ra; pop sp (with no jal in between)
+        // If we push sp and ra and later pop them, but never call a function in between, remove all four
+        // and adjust any stack pointer offsets in between by -2
+        if i + 1 < input.len() {
+            if let (
+                Instruction::Push(Operand::StackPointer),
+                Instruction::Push(Operand::ReturnAddress),
+            ) = (&input[i].instruction, &input[i + 1].instruction)
+            {
+                // Look for matching pop ra; pop sp pattern
+                if let Some((ra_pop_idx, instructions_between)) =
+                    find_matching_ra_pop(&input[i + 1..])
+                {
+                    let absolute_ra_pop = i + 1 + ra_pop_idx;
+                    // Check if the next instruction is pop sp
+                    if absolute_ra_pop + 1 < input.len() {
+                        if let Instruction::Pop(Operand::StackPointer) =
+                            &input[absolute_ra_pop + 1].instruction
+                        {
+                            // Check if there's any jal between push and pop
+                            let has_call = instructions_between.iter().any(|node| {
+                                matches!(node.instruction, Instruction::JumpAndLink(_))
+                            });
+
+                            if !has_call {
+                                // Safe to remove all four: push sp, push ra, pop ra, pop sp
+                                // Also need to adjust stack pointer offsets in between by -2
+                                let absolute_sp_pop = absolute_ra_pop + 1;
+                                // Clear output since we're going to reprocess the entire input
+                                output.clear();
+                                for (idx, node) in input.iter().enumerate() {
+                                    if idx == i
+                                        || idx == i + 1
+                                        || idx == absolute_ra_pop
+                                        || idx == absolute_sp_pop
+                                    {
+                                        // Skip all four push/pop instructions
+                                        continue;
+                                    }
+
+                                    // If this instruction is between the pushes and pops, adjust its stack offsets
+                                    if idx > i + 1 && idx < absolute_ra_pop {
+                                        let adjusted_instruction =
+                                            adjust_stack_offset(node.instruction.clone(), 2);
+                                        output.push(InstructionNode::new(
+                                            adjusted_instruction,
+                                            node.span,
+                                        ));
+                                    } else {
+                                        output.push(node.clone());
+                                    }
+                                }
+                                changed = true;
+                                // We've processed the entire input, so break
+                                break;
+                            }
+                        }
+                    }
+                }
+            }
+        }
+
+        // Pattern: push ra ... pop ra (with no jal in between)
+        // Fallback for when there's only ra push/pop without sp
+        if let Instruction::Push(Operand::ReturnAddress) = &input[i].instruction {
+            if let Some((pop_idx, instructions_between)) = find_matching_ra_pop(&input[i..]) {
+                // Check if there's any jal between push and pop
+                let has_call = instructions_between
+                    .iter()
+                    .any(|node| matches!(node.instruction, Instruction::JumpAndLink(_)));
+
+                if !has_call {
+                    // Safe to remove both push and pop
+                    // Also need to adjust stack pointer offsets in between
+                    let absolute_pop_idx = i + pop_idx;
+                    // Clear output since we're going to reprocess the entire input
+                    output.clear();
+                    for (idx, node) in input.iter().enumerate() {
+                        if idx == i || idx == absolute_pop_idx {
+                            // Skip the push and pop
+                            continue;
+                        }
+
+                        // If this instruction is between push and pop, adjust its stack offsets
+                        if idx > i && idx < absolute_pop_idx {
+                            let adjusted_instruction =
+                                adjust_stack_offset(node.instruction.clone(), 1);
+                            output.push(InstructionNode::new(adjusted_instruction, node.span));
+                        } else {
+                            output.push(node.clone());
+                        }
+                    }
+                    changed = true;
+                    // We've processed the entire input, so break
+                    break;
+                }
+            }
+        }
+
+        // Pattern: Branch-Move-Jump-Label-Move-Label -> Select
+        // beqz r1 else_label
+        // move r2 val1
+        // j end_label
+        // else_label:
+        // move r2 val2
+        // end_label:
+        // Converts to: select r2 r1 val1 val2
+        if i + 5 < input.len() {
+            let select_pattern = try_match_select_pattern(&input[i..i + 6]);
+            if let Some((dst, cond, true_val, false_val, skip_count)) = select_pattern {
+                output.push(InstructionNode::new(
+                    Instruction::Select(dst, cond, true_val, false_val),
+                    input[i].span,
+                ));
+                changed = true;
+                i += skip_count;
+                continue;
+            }
+        }
+
+        // Pattern: seq + beqz -> beq
+        if i + 1 < input.len() {
+            let pattern = match (&input[i].instruction, &input[i + 1].instruction) {
+                (
+                    Instruction::SetEq(Operand::Register(temp), a, b),
+                    Instruction::BranchEqZero(Operand::Register(cond), label),
+                ) if temp == cond => Some((a, b, label, BranchType::Eq, true)), // invert: beqz means "if NOT equal"
+
+                (
+                    Instruction::SetNe(Operand::Register(temp), a, b),
+                    Instruction::BranchEqZero(Operand::Register(cond), label),
+                ) if temp == cond => Some((a, b, label, BranchType::Ne, true)),
+
+                (
+                    Instruction::SetGt(Operand::Register(temp), a, b),
+                    Instruction::BranchEqZero(Operand::Register(cond), label),
+                ) if temp == cond => Some((a, b, label, BranchType::Gt, true)),
+
+                (
+                    Instruction::SetLt(Operand::Register(temp), a, b),
+                    Instruction::BranchEqZero(Operand::Register(cond), label),
+                ) if temp == cond => Some((a, b, label, BranchType::Lt, true)),
+
+                (
+                    Instruction::SetGe(Operand::Register(temp), a, b),
+                    Instruction::BranchEqZero(Operand::Register(cond), label),
+                ) if temp == cond => Some((a, b, label, BranchType::Ge, true)),
+
+                (
+                    Instruction::SetLe(Operand::Register(temp), a, b),
+                    Instruction::BranchEqZero(Operand::Register(cond), label),
+                ) if temp == cond => Some((a, b, label, BranchType::Le, true)),
+
+                // Pattern: seq + bnez -> bne
+                (
+                    Instruction::SetEq(Operand::Register(temp), a, b),
+                    Instruction::BranchNeZero(Operand::Register(cond), label),
+                ) if temp == cond => Some((a, b, label, BranchType::Eq, false)),
+
+                (
+                    Instruction::SetNe(Operand::Register(temp), a, b),
+                    Instruction::BranchNeZero(Operand::Register(cond), label),
+                ) if temp == cond => Some((a, b, label, BranchType::Ne, false)),
+
+                (
+                    Instruction::SetGt(Operand::Register(temp), a, b),
+                    Instruction::BranchNeZero(Operand::Register(cond), label),
+                ) if temp == cond => Some((a, b, label, BranchType::Gt, false)),
+
+                (
+                    Instruction::SetLt(Operand::Register(temp), a, b),
+                    Instruction::BranchNeZero(Operand::Register(cond), label),
+                ) if temp == cond => Some((a, b, label, BranchType::Lt, false)),
+
+                (
+                    Instruction::SetGe(Operand::Register(temp), a, b),
+                    Instruction::BranchNeZero(Operand::Register(cond), label),
+                ) if temp == cond => Some((a, b, label, BranchType::Ge, false)),
+
+                (
+                    Instruction::SetLe(Operand::Register(temp), a, b),
+                    Instruction::BranchNeZero(Operand::Register(cond), label),
+                ) if temp == cond => Some((a, b, label, BranchType::Le, false)),
+
+                _ => None,
+            };
+
+            if let Some((a, b, label, branch_type, invert)) = pattern {
+                // Create optimized branch instruction
+                let new_instr = if invert {
+                    // beqz after seq means "branch if NOT equal" -> bne
+                    match branch_type {
+                        BranchType::Eq => {
+                            Instruction::BranchNe(a.clone(), b.clone(), label.clone())
+                        }
+                        BranchType::Ne => {
+                            Instruction::BranchEq(a.clone(), b.clone(), label.clone())
+                        }
+                        BranchType::Gt => {
+                            Instruction::BranchLe(a.clone(), b.clone(), label.clone())
+                        }
+                        BranchType::Lt => {
+                            Instruction::BranchGe(a.clone(), b.clone(), label.clone())
+                        }
+                        BranchType::Ge => {
+                            Instruction::BranchLt(a.clone(), b.clone(), label.clone())
+                        }
+                        BranchType::Le => {
+                            Instruction::BranchGt(a.clone(), b.clone(), label.clone())
+                        }
+                    }
+                } else {
+                    // bnez after seq means "branch if equal" -> beq
+                    match branch_type {
+                        BranchType::Eq => {
+                            Instruction::BranchEq(a.clone(), b.clone(), label.clone())
+                        }
+                        BranchType::Ne => {
+                            Instruction::BranchNe(a.clone(), b.clone(), label.clone())
+                        }
+                        BranchType::Gt => {
+                            Instruction::BranchGt(a.clone(), b.clone(), label.clone())
+                        }
+                        BranchType::Lt => {
+                            Instruction::BranchLt(a.clone(), b.clone(), label.clone())
+                        }
+                        BranchType::Ge => {
+                            Instruction::BranchGe(a.clone(), b.clone(), label.clone())
+                        }
+                        BranchType::Le => {
+                            Instruction::BranchLe(a.clone(), b.clone(), label.clone())
+                        }
+                    }
+                };
+
+                output.push(InstructionNode::new(new_instr, input[i].span));
+                changed = true;
+                i += 2; // Skip both instructions
+                continue;
+            }
+        }
+
+        output.push(input[i].clone());
+        i += 1;
+    }
+
+    (output, changed)
+}
+
+/// Tries to match a select pattern in the instruction sequence.
+/// Pattern (6 instructions):
+///   beqz/bnez cond else_label   (i+0)
+///   move dst val1               (i+1)
+///   j end_label                 (i+2)
+///   else_label:                 (i+3)
+///   move dst val2               (i+4)
+///   end_label:                  (i+5)
+/// Returns: (dst, cond, true_val, false_val, instruction_count)
+fn try_match_select_pattern<'a>(
+    instructions: &[InstructionNode<'a>],
+) -> Option<(Operand<'a>, Operand<'a>, Operand<'a>, Operand<'a>, usize)> {
+    if instructions.len() < 6 {
+        return None;
+    }
+
+    // Check for beqz pattern
+    if let Instruction::BranchEqZero(cond, Operand::Label(else_label)) =
+        &instructions[0].instruction
+    {
+        if let Instruction::Move(dst1, val1) = &instructions[1].instruction {
+            if let Instruction::Jump(Operand::Label(end_label)) = &instructions[2].instruction {
+                if let Instruction::LabelDef(label3) = &instructions[3].instruction {
+                    if label3 == else_label {
+                        if let Instruction::Move(dst2, val2) = &instructions[4].instruction {
+                            if dst1 == dst2 {
+                                if let Instruction::LabelDef(label5) = &instructions[5].instruction
+                                {
+                                    if label5 == end_label {
+                                        // beqz means: if cond==0, goto else, so val1 is for true, val2 for false
+                                        // select dst cond true_val false_val
+                                        // When cond is non-zero (true), use val1, otherwise val2
+                                        return Some((
+                                            dst1.clone(),
+                                            cond.clone(),
+                                            val1.clone(),
+                                            val2.clone(),
+                                            6,
+                                        ));
+                                    }
+                                }
+                            }
+                        }
+                    }
+                }
+            }
+        }
+    }
+
+    // Check for bnez pattern
+    if let Instruction::BranchNeZero(cond, Operand::Label(then_label)) =
+        &instructions[0].instruction
+    {
+        if let Instruction::Move(dst1, val_false) = &instructions[1].instruction {
+            if let Instruction::Jump(Operand::Label(end_label)) = &instructions[2].instruction {
+                if let Instruction::LabelDef(label3) = &instructions[3].instruction {
+                    if label3 == then_label {
+                        if let Instruction::Move(dst2, val_true) = &instructions[4].instruction {
+                            if dst1 == dst2 {
+                                if let Instruction::LabelDef(label5) = &instructions[5].instruction
+                                {
+                                    if label5 == end_label {
+                                        // bnez means: if cond!=0, goto then, so val_true for true, val_false for false
+                                        return Some((
+                                            dst1.clone(),
+                                            cond.clone(),
+                                            val_true.clone(),
+                                            val_false.clone(),
+                                            6,
+                                        ));
+                                    }
+                                }
+                            }
+                        }
+                    }
+                }
+            }
+        }
+    }
+
+    None
+}
+
+/// Finds a matching `pop ra` for a `push ra` at the start of the slice.
+/// Returns the index of the pop and the instructions in between.
+fn find_matching_ra_pop<'a>(
+    instructions: &'a [InstructionNode<'a>],
+) -> Option<(usize, &'a [InstructionNode<'a>])> {
+    if instructions.is_empty() {
+        return None;
+    }
+
+    // Skip the push itself
+    for (idx, node) in instructions.iter().enumerate().skip(1) {
+        if let Instruction::Pop(Operand::ReturnAddress) = &node.instruction {
+            // Found matching pop
+            return Some((idx, &instructions[1..idx]));
+        }
+
+        // Stop searching if we hit a jump (different control flow) or a function label
+        // Labels are OK - they're just markers EXCEPT for user-defined function labels
+        // which indicate a function boundary
+        if matches!(
+            node.instruction,
+            Instruction::Jump(_) | Instruction::JumpRelative(_) | Instruction::LabelDef(_)
+        ) {
+            return None;
+        }
+    }
+
+    None
+}
+
+/// Checks if an instruction uses or modifies the stack pointer.
+#[allow(dead_code)]
+fn uses_stack_pointer(instruction: &Instruction) -> bool {
+    match instruction {
+        Instruction::Push(_) | Instruction::Pop(_) | Instruction::Peek(_) => true,
+        Instruction::Add(Operand::StackPointer, _, _)
+        | Instruction::Sub(Operand::StackPointer, _, _)
+        | Instruction::Mul(Operand::StackPointer, _, _)
+        | Instruction::Div(Operand::StackPointer, _, _)
+        | Instruction::Mod(Operand::StackPointer, _, _) => true,
+        Instruction::Add(_, Operand::StackPointer, _)
+        | Instruction::Sub(_, Operand::StackPointer, _)
+        | Instruction::Mul(_, Operand::StackPointer, _)
+        | Instruction::Div(_, Operand::StackPointer, _)
+        | Instruction::Mod(_, Operand::StackPointer, _) => true,
+        Instruction::Add(_, _, Operand::StackPointer)
+        | Instruction::Sub(_, _, Operand::StackPointer)
+        | Instruction::Mul(_, _, Operand::StackPointer)
+        | Instruction::Div(_, _, Operand::StackPointer)
+        | Instruction::Mod(_, _, Operand::StackPointer) => true,
+        Instruction::Move(Operand::StackPointer, _)
+        | Instruction::Move(_, Operand::StackPointer) => true,
+        _ => false,
+    }
+}
+
+/// Adjusts stack pointer offsets in an instruction by decrementing them by a given amount.
+/// This is necessary when removing push operations that would have increased the stack size.
+fn adjust_stack_offset<'a>(instruction: Instruction<'a>, decrement: i64) -> Instruction<'a> {
+    use rust_decimal::prelude::*;
+
+    match instruction {
+        // Adjust arithmetic operations on sp that use literal offsets
+        Instruction::Sub(dst, Operand::StackPointer, Operand::Number(n)) => {
+            let new_n = n - Decimal::from(decrement);
+            // If the result is 0 or negative, we may want to skip this entirely
+            // but for now, just adjust the value
+            Instruction::Sub(dst, Operand::StackPointer, Operand::Number(new_n))
+        }
+        Instruction::Add(dst, Operand::StackPointer, Operand::Number(n)) => {
+            let new_n = n - Decimal::from(decrement);
+            Instruction::Add(dst, Operand::StackPointer, Operand::Number(new_n))
+        }
+        // Return the instruction unchanged if it doesn't need adjustment
+        other => other,
+    }
+}
+
+#[derive(Debug, Clone, Copy)]
+enum BranchType {
+    Eq,
+    Ne,
+    Gt,
+    Lt,
+    Ge,
+    Le,
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_seq_beqz_to_bne() {
+        let input = vec![
+            InstructionNode::new(
+                Instruction::SetEq(
+                    Operand::Register(1),
+                    Operand::Register(2),
+                    Operand::Register(3),
+                ),
+                None,
+            ),
+            InstructionNode::new(
+                Instruction::BranchEqZero(Operand::Register(1), Operand::Label("target".into())),
+                None,
+            ),
+        ];
+
+        let (output, changed) = peephole_optimization(input);
+        assert!(changed);
+        assert_eq!(output.len(), 1);
+        assert!(matches!(
+            output[0].instruction,
+            Instruction::BranchNe(_, _, _)
+        ));
+    }
+
+    #[test]
+    fn test_sne_beqz_to_beq() {
+        let input = vec![
+            InstructionNode::new(
+                Instruction::SetNe(
+                    Operand::Register(1),
+                    Operand::Register(2),
+                    Operand::Register(3),
+                ),
+                None,
+            ),
+            InstructionNode::new(
+                Instruction::BranchEqZero(Operand::Register(1), Operand::Label("target".into())),
+                None,
+            ),
+        ];
+
+        let (output, changed) = peephole_optimization(input);
+        assert!(changed);
+        assert_eq!(output.len(), 1);
+        assert!(matches!(
+            output[0].instruction,
+            Instruction::BranchEq(_, _, _)
+        ));
+    }
+
+    #[test]
+    fn test_seq_bnez_to_beq() {
+        let input = vec![
+            InstructionNode::new(
+                Instruction::SetEq(
+                    Operand::Register(1),
+                    Operand::Register(2),
+                    Operand::Register(3),
+                ),
+                None,
+            ),
+            InstructionNode::new(
+                Instruction::BranchNeZero(Operand::Register(1), Operand::Label("target".into())),
+                None,
+            ),
+        ];
+
+        let (output, changed) = peephole_optimization(input);
+        assert!(changed);
+        assert_eq!(output.len(), 1);
+        assert!(matches!(
+            output[0].instruction,
+            Instruction::BranchEq(_, _, _)
+        ));
+    }
+
+    #[test]
+    fn test_sgt_beqz_to_ble() {
+        let input = vec![
+            InstructionNode::new(
+                Instruction::SetGt(
+                    Operand::Register(1),
+                    Operand::Register(2),
+                    Operand::Register(3),
+                ),
+                None,
+            ),
+            InstructionNode::new(
+                Instruction::BranchEqZero(Operand::Register(1), Operand::Label("target".into())),
+                None,
+            ),
+        ];
+
+        let (output, changed) = peephole_optimization(input);
+        assert!(changed);
+        assert_eq!(output.len(), 1);
+        assert!(matches!(
+            output[0].instruction,
+            Instruction::BranchLe(_, _, _)
+        ));
+    }
+
+    #[test]
+    fn test_branch_move_jump_to_select_beqz() {
+        // Pattern: beqz r1 else / move r2 10 / j end / else: / move r2 20 / end:
+        // Should convert to: select r2 r1 10 20
+        let input = vec![
+            InstructionNode::new(
+                Instruction::BranchEqZero(Operand::Register(1), Operand::Label("else".into())),
+                None,
+            ),
+            InstructionNode::new(
+                Instruction::Move(Operand::Register(2), Operand::Number(10.into())),
+                None,
+            ),
+            InstructionNode::new(Instruction::Jump(Operand::Label("end".into())), None),
+            InstructionNode::new(Instruction::LabelDef("else".into()), None),
+            InstructionNode::new(
+                Instruction::Move(Operand::Register(2), Operand::Number(20.into())),
+                None,
+            ),
+            InstructionNode::new(Instruction::LabelDef("end".into()), None),
+        ];
+
+        let (output, changed) = peephole_optimization(input);
+        assert!(changed);
+        assert_eq!(output.len(), 1);
+        if let Instruction::Select(dst, cond, true_val, false_val) = &output[0].instruction {
+            assert!(matches!(dst, Operand::Register(2)));
+            assert!(matches!(cond, Operand::Register(1)));
+            assert!(matches!(true_val, Operand::Number(_)));
+            assert!(matches!(false_val, Operand::Number(_)));
+        } else {
+            panic!("Expected Select instruction");
+        }
+    }
+
+    #[test]
+    fn test_branch_move_jump_to_select_bnez() {
+        // Pattern: bnez r1 then / move r2 20 / j end / then: / move r2 10 / end:
+        // Should convert to: select r2 r1 10 20
+        let input = vec![
+            InstructionNode::new(
+                Instruction::BranchNeZero(Operand::Register(1), Operand::Label("then".into())),
+                None,
+            ),
+            InstructionNode::new(
+                Instruction::Move(Operand::Register(2), Operand::Number(20.into())),
+                None,
+            ),
+            InstructionNode::new(Instruction::Jump(Operand::Label("end".into())), None),
+            InstructionNode::new(Instruction::LabelDef("then".into()), None),
+            InstructionNode::new(
+                Instruction::Move(Operand::Register(2), Operand::Number(10.into())),
+                None,
+            ),
+            InstructionNode::new(Instruction::LabelDef("end".into()), None),
+        ];
+
+        let (output, changed) = peephole_optimization(input);
+        assert!(changed);
+        assert_eq!(output.len(), 1);
+        if let Instruction::Select(dst, cond, true_val, false_val) = &output[0].instruction {
+            assert!(matches!(dst, Operand::Register(2)));
+            assert!(matches!(cond, Operand::Register(1)));
+            assert!(matches!(true_val, Operand::Number(_)));
+            assert!(matches!(false_val, Operand::Number(_)));
+        } else {
+            panic!("Expected Select instruction");
+        }
+    }
+
+    #[test]
+    fn test_remove_useless_ra_push_pop() {
+        // Pattern: push ra / add r1 r2 r3 / pop ra
+        // Should remove both push and pop since no jal in between
+        let input = vec![
+            InstructionNode::new(Instruction::Push(Operand::ReturnAddress), None),
+            InstructionNode::new(
+                Instruction::Add(
+                    Operand::Register(1),
+                    Operand::Register(2),
+                    Operand::Register(3),
+                ),
+                None,
+            ),
+            InstructionNode::new(Instruction::Pop(Operand::ReturnAddress), None),
+        ];
+
+        let (output, changed) = peephole_optimization(input);
+        assert!(changed);
+        assert_eq!(output.len(), 1);
+        assert!(matches!(output[0].instruction, Instruction::Add(_, _, _)));
+    }
+
+    #[test]
+    fn test_keep_ra_push_pop_with_jal() {
+        // Pattern: push ra / jal func / pop ra
+        // Should keep both since there's a jal in between
+        let input = vec![
+            InstructionNode::new(Instruction::Push(Operand::ReturnAddress), None),
+            InstructionNode::new(
+                Instruction::JumpAndLink(Operand::Label("func".into())),
+                None,
+            ),
+            InstructionNode::new(Instruction::Pop(Operand::ReturnAddress), None),
+        ];
+
+        let (output, changed) = peephole_optimization(input);
+        assert!(!changed);
+        assert_eq!(output.len(), 3);
+    }
+
+    #[test]
+    fn test_ra_push_pop_with_stack_offset_adjustment() {
+        // Pattern: push ra / sub r1 sp 2 / pop ra
+        // Should remove push/pop AND adjust the stack offset from 2 to 1
+        use rust_decimal::prelude::*;
+
+        let input = vec![
+            InstructionNode::new(Instruction::Push(Operand::ReturnAddress), None),
+            InstructionNode::new(
+                Instruction::Sub(
+                    Operand::Register(1),
+                    Operand::StackPointer,
+                    Operand::Number(Decimal::from(2)),
+                ),
+                None,
+            ),
+            InstructionNode::new(Instruction::Pop(Operand::ReturnAddress), None),
+        ];
+
+        let (output, changed) = peephole_optimization(input);
+        assert!(changed);
+        assert_eq!(output.len(), 1);
+
+        if let Instruction::Sub(dst, src, Operand::Number(offset)) = &output[0].instruction {
+            assert!(matches!(dst, Operand::Register(1)));
+            assert!(matches!(src, Operand::StackPointer));
+            assert_eq!(*offset, Decimal::from(1)); // Should be decremented from 2 to 1
+        } else {
+            panic!("Expected Sub instruction with adjusted offset");
+        }
+    }
+
+    #[test]
+    fn test_remove_sp_and_ra_push_pop() {
+        // Pattern: push sp / push ra / move r8 10 / pop ra / pop sp
+        // Should remove all four push/pop instructions since no jal in between
+        let input = vec![
+            InstructionNode::new(Instruction::Push(Operand::StackPointer), None),
+            InstructionNode::new(Instruction::Push(Operand::ReturnAddress), None),
+            InstructionNode::new(
+                Instruction::Move(Operand::Register(8), Operand::Number(10.into())),
+                None,
+            ),
+            InstructionNode::new(Instruction::Pop(Operand::ReturnAddress), None),
+            InstructionNode::new(Instruction::Pop(Operand::StackPointer), None),
+        ];
+
+        let (output, changed) = peephole_optimization(input);
+        assert!(changed);
+        assert_eq!(output.len(), 1);
+        assert!(matches!(
+            output[0].instruction,
+            Instruction::Move(Operand::Register(8), _)
+        ));
+    }
+
+    #[test]
+    fn test_keep_sp_and_ra_push_pop_with_jal() {
+        // Pattern: push sp / push ra / jal func / pop ra / pop sp
+        // Should keep all since there's a jal in between
+        let input = vec![
+            InstructionNode::new(Instruction::Push(Operand::StackPointer), None),
+            InstructionNode::new(Instruction::Push(Operand::ReturnAddress), None),
+            InstructionNode::new(
+                Instruction::JumpAndLink(Operand::Label("func".into())),
+                None,
+            ),
+            InstructionNode::new(Instruction::Pop(Operand::ReturnAddress), None),
+            InstructionNode::new(Instruction::Pop(Operand::StackPointer), None),
+        ];
+
+        let (output, changed) = peephole_optimization(input);
+        assert!(!changed);
+        assert_eq!(output.len(), 5);
+    }
+
+    #[test]
+    fn test_sp_and_ra_with_stack_offset_adjustment() {
+        // Pattern: push sp / push ra / sub r1 sp 3 / pop ra / pop sp
+        // Should remove all push/pop AND adjust the stack offset from 3 to 1 (decrement by 2)
+        use rust_decimal::prelude::*;
+
+        let input = vec![
+            InstructionNode::new(Instruction::Push(Operand::StackPointer), None),
+            InstructionNode::new(Instruction::Push(Operand::ReturnAddress), None),
+            InstructionNode::new(
+                Instruction::Sub(
+                    Operand::Register(1),
+                    Operand::StackPointer,
+                    Operand::Number(Decimal::from(3)),
+                ),
+                None,
+            ),
+            InstructionNode::new(Instruction::Pop(Operand::ReturnAddress), None),
+            InstructionNode::new(Instruction::Pop(Operand::StackPointer), None),
+        ];
+
+        let (output, changed) = peephole_optimization(input);
+        assert!(changed);
+        assert_eq!(output.len(), 1);
+
+        if let Instruction::Sub(dst, src, Operand::Number(offset)) = &output[0].instruction {
+            assert!(matches!(dst, Operand::Register(1)));
+            assert!(matches!(src, Operand::StackPointer));
+            assert_eq!(*offset, Decimal::from(1)); // Should be decremented from 3 to 1
+        } else {
+            panic!("Expected Sub instruction with adjusted offset");
+        }
+    }
+}

rust_compiler/libs/optimizer/src/register_forwarding.rs

@@ -0,0 +1,151 @@
+use crate::helpers::{get_destination_reg, reg_is_read, set_destination_reg};
+use il::{Instruction, InstructionNode, Operand};
+use std::collections::HashMap;
+
+/// Pass: Register Forwarding
+/// Eliminates intermediate moves by writing directly to the final destination.
+/// Example: `l r1 d0 Temperature` + `move r9 r1` -> `l r9 d0 Temperature`
+pub fn register_forwarding<'a>(
+    mut input: Vec<InstructionNode<'a>>,
+) -> (Vec<InstructionNode<'a>>, bool) {
+    let mut changed = false;
+    let mut i = 0;
+
+    // Build a map of label positions to detect backward jumps
+    // Use String keys to avoid lifetime issues with references into input
+    let label_positions: HashMap<String, usize> = input
+        .iter()
+        .enumerate()
+        .filter_map(|(idx, node)| {
+            if let Instruction::LabelDef(label) = &node.instruction {
+                Some((label.to_string(), idx))
+            } else {
+                None
+            }
+        })
+        .collect();
+
+    while i < input.len().saturating_sub(1) {
+        let next_idx = i + 1;
+
+        // Check if current instruction defines a register
+        // and the NEXT instruction is a move from that register.
+        let forward_candidate = if let Some(def_reg) = get_destination_reg(&input[i].instruction) {
+            if let Instruction::Move(
+                il::Operand::Register(dest_reg),
+                il::Operand::Register(src_reg),
+            ) = &input[next_idx].instruction
+            {
+                if *src_reg == def_reg {
+                    Some((def_reg, *dest_reg))
+                } else {
+                    None
+                }
+            } else {
+                None
+            }
+        } else {
+            None
+        };
+
+        if let Some((temp_reg, final_reg)) = forward_candidate {
+            // Check liveness: Is temp_reg used after i+1?
+            let mut temp_is_dead = true;
+            for node in input.iter().skip(i + 2) {
+                if reg_is_read(&node.instruction, temp_reg) {
+                    temp_is_dead = false;
+                    break;
+                }
+                // If the temp is redefined, then the old value is dead
+                if let Some(redef) = get_destination_reg(&node.instruction)
+                    && redef == temp_reg
+                {
+                    break;
+                }
+
+                // Function calls (jal) clobber the return register (r15)
+                // So if we're tracking r15 and hit a function call, the old value is dead
+                if matches!(node.instruction, Instruction::JumpAndLink(_)) && temp_reg == 15 {
+                    break;
+                }
+
+                // Labels are just markers - they don't affect register liveness
+                // But backward jumps create loops we need to analyze carefully
+                let jump_target = match &node.instruction {
+                    Instruction::Jump(Operand::Label(target)) => Some(target.as_ref()),
+                    Instruction::BranchEq(_, _, Operand::Label(target))
+                    | Instruction::BranchNe(_, _, Operand::Label(target))
+                    | Instruction::BranchGt(_, _, Operand::Label(target))
+                    | Instruction::BranchLt(_, _, Operand::Label(target))
+                    | Instruction::BranchGe(_, _, Operand::Label(target))
+                    | Instruction::BranchLe(_, _, Operand::Label(target))
+                    | Instruction::BranchEqZero(_, Operand::Label(target))
+                    | Instruction::BranchNeZero(_, Operand::Label(target)) => Some(target.as_ref()),
+                    _ => None,
+                };
+
+                if let Some(target) = jump_target {
+                    // Check if this is a backward jump (target appears before current position)
+                    if let Some(&target_pos) = label_positions.get(target) {
+                        if target_pos < i {
+                            // Backward jump - could loop back, register might be live
+                            temp_is_dead = false;
+                            break;
+                        }
+                        // Forward jump is OK - doesn't affect liveness before it
+                    }
+                }
+            }
+
+            if temp_is_dead {
+                // Safety check: ensure final_reg is not used as an operand in the current instruction.
+                // This prevents generating invalid instructions like `sub r5 r0 r5` (read and write same register).
+                if !reg_is_read(&input[i].instruction, final_reg) {
+                    // Rewrite to use final destination directly
+                    if let Some(new_instr) = set_destination_reg(&input[i].instruction, final_reg) {
+                        input[i].instruction = new_instr;
+                        input.remove(next_idx);
+                        changed = true;
+                        continue;
+                    }
+                }
+            }
+        }
+
+        i += 1;
+    }
+
+    (input, changed)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use il::{Instruction, InstructionNode, Operand};
+
+    #[test]
+    fn test_forward_simple_move() {
+        let input = vec![
+            InstructionNode::new(
+                Instruction::Add(
+                    Operand::Register(1),
+                    Operand::Register(2),
+                    Operand::Register(3),
+                ),
+                None,
+            ),
+            InstructionNode::new(
+                Instruction::Move(Operand::Register(5), Operand::Register(1)),
+                None,
+            ),
+        ];
+
+        let (output, changed) = register_forwarding(input);
+        assert!(changed);
+        assert_eq!(output.len(), 1);
+        assert!(matches!(
+            output[0].instruction,
+            Instruction::Add(Operand::Register(5), _, _)
+        ));
+    }
+}

rust_compiler/libs/optimizer/src/strength_reduction.rs

@@ -0,0 +1,63 @@
+use il::{Instruction, InstructionNode, Operand};
+use rust_decimal::Decimal;
+
+/// Pass: Strength Reduction
+/// Replaces expensive operations with cheaper equivalents.
+/// Example: x * 2 -> add x x x (addition is typically faster than multiplication)
+pub fn strength_reduction<'a>(
+    input: Vec<InstructionNode<'a>>,
+) -> (Vec<InstructionNode<'a>>, bool) {
+    let mut output = Vec::with_capacity(input.len());
+    let mut changed = false;
+
+    for mut node in input {
+        let reduced = match &node.instruction {
+            // x * 2 = x + x
+            Instruction::Mul(dst, a, Operand::Number(n)) if *n == Decimal::from(2) => {
+                Some(Instruction::Add(dst.clone(), a.clone(), a.clone()))
+            }
+            Instruction::Mul(dst, Operand::Number(n), b) if *n == Decimal::from(2) => {
+                Some(Instruction::Add(dst.clone(), b.clone(), b.clone()))
+            }
+
+            // Future: Could add power-of-2 optimizations using bit shifts if IC10 supports them
+            // x * 4 = (x + x) + (x + x) or x << 2
+            // x / 2 = x >> 1
+
+            _ => None,
+        };
+
+        if let Some(new) = reduced {
+            node.instruction = new;
+            changed = true;
+        }
+
+        output.push(node);
+    }
+
+    (output, changed)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_mul_two_to_add() {
+        let input = vec![InstructionNode::new(
+            Instruction::Mul(
+                Operand::Register(1),
+                Operand::Register(2),
+                Operand::Number(Decimal::from(2)),
+            ),
+            None,
+        )];
+
+        let (output, changed) = strength_reduction(input);
+        assert!(changed);
+        assert!(matches!(
+            output[0].instruction,
+            Instruction::Add(Operand::Register(1), Operand::Register(2), Operand::Register(2))
+        ));
+    }
+}