HGlobalValueNumberingPhase::HGlobalValueNumberingPhase(HGraph* graph)
- : HPhase("H_Global value numbering", graph),
- removed_side_effects_(false),
- block_side_effects_(graph->blocks()->length(), zone()),
- loop_side_effects_(graph->blocks()->length(), zone()),
- visited_on_paths_(graph->blocks()->length(), zone()) {
- ASSERT(!AllowHandleAllocation::IsAllowed());
- block_side_effects_.AddBlock(GVNFlagSet(), graph->blocks()->length(),
- zone());
- loop_side_effects_.AddBlock(GVNFlagSet(), graph->blocks()->length(),
+ : HPhase("H_Global value numbering", graph),
+ removed_side_effects_(false),
+ block_side_effects_(graph->blocks()->length(), zone()),
+ loop_side_effects_(graph->blocks()->length(), zone()),
+ visited_on_paths_(graph->blocks()->length(), zone()) {
+ ASSERT(!AllowHandleAllocation::IsAllowed());
+ block_side_effects_.AddBlock(GVNFlagSet(), graph->blocks()->length(),
zone());
+ loop_side_effects_.AddBlock(GVNFlagSet(), graph->blocks()->length(),
+ zone());
}
-void HGlobalValueNumberingPhase::Reset() {
- ASSERT(block_side_effects_.length() == graph()->blocks()->length());
- ASSERT(loop_side_effects_.length() == graph()->blocks()->length());
- for (int i = 0; i < graph()->blocks()->length(); ++i) {
- block_side_effects_[i] = GVNFlagSet();
- loop_side_effects_[i] = GVNFlagSet();
- }
- visited_on_paths_.Clear();
-}
+void HGlobalValueNumberingPhase::Run() {
+ ASSERT(!removed_side_effects_);
+ for (int i = FLAG_gvn_iterations; i > 0; --i) {
+ // Compute the side effects.
+ ComputeBlockSideEffects();
+
+ // Perform loop invariant code motion if requested.
+ if (FLAG_loop_invariant_code_motion) LoopInvariantCodeMotion();
+ // Perform the actual value numbering.
+ AnalyzeGraph();
-void HGlobalValueNumberingPhase::Analyze() {
- removed_side_effects_ = false;
- ComputeBlockSideEffects();
- if (FLAG_loop_invariant_code_motion) {
- LoopInvariantCodeMotion();
+ // Continue GVN if we removed any side effects.
+ if (!removed_side_effects_) break;
+ removed_side_effects_ = false;
+
+ // Clear all side effects.
+ ASSERT_EQ(block_side_effects_.length(), graph()->blocks()->length());
+ ASSERT_EQ(loop_side_effects_.length(), graph()->blocks()->length());
+ for (int i = 0; i < graph()->blocks()->length(); ++i) {
+ block_side_effects_[i].RemoveAll();
+ loop_side_effects_[i].RemoveAll();
+ }
+ visited_on_paths_.Clear();
}
- AnalyzeGraph();
}
void HGlobalValueNumberingPhase::ComputeBlockSideEffects() {
- // The Analyze phase of GVN can be called multiple times. Clear loop side
- // effects before computing them to erase the contents from previous Analyze
- // passes.
- for (int i = 0; i < loop_side_effects_.length(); ++i) {
- loop_side_effects_[i].RemoveAll();
- }
for (int i = graph()->blocks()->length() - 1; i >= 0; --i) {
// Compute side effects for the block.
HBasicBlock* block = graph()->blocks()->at(i);