Run mem2reg a lot

EmbarkStudios · May 21, 2021 · 9261670 · 9261670
1 parent dcb103b
commit 9261670
Showing 1 changed file with 22 additions and 12 deletions.
diff --git a/crates/rustc_codegen_spirv/src/linker/mem2reg.rs b/crates/rustc_codegen_spirv/src/linker/mem2reg.rs
@@ -27,14 +27,14 @@ pub fn mem2reg(
  let preds = compute_preds(&func.blocks, &reachable);
  let idom = compute_idom(&preds, &reachable);
  let dominance_frontier = compute_dominance_frontier(&preds, &idom);
- insert_phis_all(
+ while insert_phis_all(
  header,
  types_global_values,
  pointer_to_pointee,
  constants,
  &mut func.blocks,
- dominance_frontier,
- );
+ &dominance_frontier,
+ ) {}
 }
 
 fn label_to_index(blocks: &[Block], id: Word) -> usize {
@@ -146,15 +146,16 @@ fn compute_dominance_frontier(
  dominance_frontier
 }
 
+// Returns true if variables were rewritten
 fn insert_phis_all(
  header: &mut ModuleHeader,
  types_global_values: &mut Vec<Instruction>,
  pointer_to_pointee: &FxHashMap<Word, Word>,
  constants: &FxHashMap<Word, u32>,
  blocks: &mut [Block],
- dominance_frontier: Vec<FxHashSet<usize>>,
-) {
- let thing = blocks[0]
+ dominance_frontier: &[FxHashSet<usize>],
+) -> bool {
+ let var_maps_and_types = blocks[0]
  .instructions
  .iter()
  .filter(|inst| inst.class.opcode == Op::Variable)
@@ -167,8 +168,11 @@ fn insert_phis_all(
  ))
  })
  .collect::<Vec<_>>();
- for &(ref var_map, base_var_type) in &thing {
- let blocks_with_phi = insert_phis(blocks, &dominance_frontier, var_map);
+ if var_maps_and_types.is_empty() {
+ return false;
+ }
+ for &(ref var_map, base_var_type) in &var_maps_and_types {
+ let blocks_with_phi = insert_phis(blocks, dominance_frontier, var_map);
  let mut renamer = Renamer {
  header,
  types_global_values,
@@ -185,7 +189,8 @@ fn insert_phis_all(
  apply_rewrite_rules(&renamer.rewrite_rules, blocks);
  remove_nops(blocks);
  }
- remove_old_variables(blocks, &thing);
+ remove_old_variables(blocks, &var_maps_and_types);
+ true
 }
 
 #[derive(Debug)]
@@ -488,11 +493,14 @@ fn remove_nops(blocks: &mut [Block]) {
  }
 }
 
-fn remove_old_variables(blocks: &mut [Block], thing: &[(FxHashMap<u32, VarInfo>, u32)]) {
+fn remove_old_variables(
+ blocks: &mut [Block],
+ var_maps_and_types: &[(FxHashMap<u32, VarInfo>, u32)],
+) {
  blocks[0].instructions.retain(|inst| {
  inst.class.opcode != Op::Variable || {
  let result_id = inst.result_id.unwrap();
- thing
+ var_maps_and_types
  .iter()
  .all(|(var_map, _)| !var_map.contains_key(&result_id))
  }
@@ -502,7 +510,9 @@ fn remove_old_variables(blocks: &mut [Block], thing: &[(FxHashMap<u32, VarInfo>,
  !matches!(inst.class.opcode, Op::AccessChain | Op::InBoundsAccessChain)
  || inst.operands.iter().all(|op| {
  op.id_ref_any().map_or(true, |id| {
- thing.iter().all(|(var_map, _)| !var_map.contains_key(&id))
+ var_maps_and_types
+ .iter()
+ .all(|(var_map, _)| !var_map.contains_key(&id))
  })
  })
  })