wave_compiler/optimize/
mod.rs

1// Copyright 2026 Ojima Abraham
2// SPDX-License-Identifier: Apache-2.0
3
4//! Optimization pipeline for MIR.
5//!
6//! Includes dead code elimination, common subexpression elimination,
7//! constant folding, loop-invariant code motion, strength reduction,
8//! SCCP, mem2reg, loop unrolling, and CFG simplification.
9//! Passes are run in a fixed order until no pass reports changes.
10
11pub mod constant_fold;
12pub mod cse;
13pub mod dce;
14pub mod licm;
15pub mod loop_unroll;
16pub mod mem2reg;
17pub mod pass;
18pub mod sccp;
19pub mod simplify_cfg;
20pub mod strength_reduce;
21
22use crate::driver::config::OptLevel;
23use crate::mir::function::MirFunction;
24use pass::Pass;
25
26/// Run the optimization pipeline on a MIR function at the given optimization level.
27pub fn optimize(func: &mut MirFunction, opt_level: OptLevel) {
28    let passes: Vec<Box<dyn Pass>> = match opt_level {
29        OptLevel::O0 => vec![],
30        OptLevel::O1 => vec![
31            Box::new(mem2reg::Mem2Reg),
32            Box::new(constant_fold::ConstantFold),
33            Box::new(dce::Dce),
34            Box::new(simplify_cfg::SimplifyCfg),
35        ],
36        OptLevel::O2 => vec![
37            Box::new(mem2reg::Mem2Reg),
38            Box::new(sccp::Sccp),
39            Box::new(dce::Dce),
40            Box::new(cse::Cse),
41            Box::new(licm::Licm),
42            Box::new(strength_reduce::StrengthReduce),
43            Box::new(simplify_cfg::SimplifyCfg),
44            Box::new(dce::Dce),
45        ],
46        OptLevel::O3 => vec![
47            Box::new(mem2reg::Mem2Reg),
48            Box::new(sccp::Sccp),
49            Box::new(dce::Dce),
50            Box::new(cse::Cse),
51            Box::new(licm::Licm),
52            Box::new(loop_unroll::LoopUnroll),
53            Box::new(strength_reduce::StrengthReduce),
54            Box::new(simplify_cfg::SimplifyCfg),
55            Box::new(dce::Dce),
56        ],
57    };
58
59    let mut changed = true;
60    let mut iterations = 0;
61    while changed && iterations < 10 {
62        changed = false;
63        for pass in &passes {
64            changed |= pass.run(func);
65        }
66        iterations += 1;
67    }
68}
69
70#[cfg(test)]
71mod tests {
72    use super::*;
73    use crate::mir::basic_block::{BasicBlock, Terminator};
74    use crate::mir::instruction::{ConstValue, MirInst};
75    use crate::mir::value::{BlockId, ValueId};
76
77    #[test]
78    fn test_optimize_o0_no_changes() {
79        let mut func = MirFunction::new("test".into(), BlockId(0));
80        let mut bb = BasicBlock::new(BlockId(0));
81        bb.instructions.push(MirInst::Const {
82            dest: ValueId(0),
83            value: ConstValue::I32(42),
84        });
85        bb.terminator = Terminator::Return;
86        func.blocks.push(bb);
87
88        optimize(&mut func, OptLevel::O0);
89        assert_eq!(func.blocks[0].instructions.len(), 1);
90    }
91
92    #[test]
93    fn test_optimize_o1_removes_dead_code() {
94        let mut func = MirFunction::new("test".into(), BlockId(0));
95        let mut bb = BasicBlock::new(BlockId(0));
96        bb.instructions.push(MirInst::Const {
97            dest: ValueId(0),
98            value: ConstValue::I32(42),
99        });
100        bb.instructions.push(MirInst::Const {
101            dest: ValueId(1),
102            value: ConstValue::I32(99),
103        });
104        bb.terminator = Terminator::Return;
105        func.blocks.push(bb);
106
107        optimize(&mut func, OptLevel::O1);
108        assert!(func.blocks[0].instructions.is_empty());
109    }
110}
wave_compiler/optimize/mod.rs

wave_compiler/optimize/
mod.rs
