AuroraMiddleware/v8
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Start immediate dominator propagation at entry to floating control.

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R=titzer@chromium.org

Review URL: https://codereview.chromium.org/761673004

Cr-Commit-Position: refs/heads/master@{#25543}
This commit is contained in:
mstarzinger 2014-11-27 04:00:30 -08:00 committed by Commit bot
parent 9724ede898
commit 9f1bc698ad
2 changed files with 18 additions and 13 deletions
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30
src/compiler/scheduler.cc
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@ -1037,15 +1037,8 @@ void Scheduler::ComputeSpecialRPONumbering() {
}
void Scheduler::GenerateImmediateDominatorTree() {
Trace("--- IMMEDIATE BLOCK DOMINATORS -----------------------------\n");
// TODO(danno): Consider using Lengauer & Tarjan's if this becomes too slow.
// Build the block dominator tree.
schedule_->start()->set_dominator_depth(0);
BasicBlock* second = schedule_->start()->rpo_next();
for (BasicBlock* block = second; block != NULL; block = block->rpo_next()) {
void Scheduler::PropagateImmediateDominators(BasicBlock* block) {
for (/*nop*/; block != NULL; block = block->rpo_next()) {
BasicBlock::Predecessors::iterator pred = block->predecessors_begin();
BasicBlock::Predecessors::iterator end = block->predecessors_end();
DCHECK(pred != end); // All blocks except start have predecessors.
@ -1068,6 +1061,17 @@ void Scheduler::GenerateImmediateDominatorTree() {
}
void Scheduler::GenerateImmediateDominatorTree() {
Trace("--- IMMEDIATE BLOCK DOMINATORS -----------------------------\n");
// Seed start block to be the first dominator.
schedule_->start()->set_dominator_depth(0);
// Build the block dominator tree resulting from the above seed.
PropagateImmediateDominators(schedule_->start()->rpo_next());
}
// -----------------------------------------------------------------------------
// Phase 3: Prepare use counts for nodes.
@ -1434,11 +1438,11 @@ void Scheduler::FuseFloatingControl(BasicBlock* block, Node* node) {
// Iterate on phase 2: Compute special RPO and dominator tree.
special_rpo_->UpdateSpecialRPO(block, schedule_->block(node));
// TODO(mstarzinger): Currently "iterate on" means "re-run". Fix that.
for (BasicBlock* block : schedule_->all_blocks_) {
block->set_dominator_depth(-1);
block->set_dominator(NULL);
for (BasicBlock* b = block->rpo_next(); b != NULL; b = b->rpo_next()) {
b->set_dominator_depth(-1);
b->set_dominator(NULL);
}
GenerateImmediateDominatorTree();
PropagateImmediateDominators(block->rpo_next());
// Iterate on phase 4: Schedule nodes early.
// TODO(mstarzinger): The following loop gathering the propagation roots is a

1
src/compiler/scheduler.h
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@ -78,6 +78,7 @@ class Scheduler {
void DecrementUnscheduledUseCount(Node* node, int index, Node* from);
BasicBlock* GetCommonDominator(BasicBlock* b1, BasicBlock* b2);
void PropagateImmediateDominators(BasicBlock* block);
// Phase 1: Build control-flow graph.
friend class CFGBuilder;