Reviewers: Hannes Payer,
Message:
Committed patchset #1 manually as r19932 (tree was closed).
Description:
Revert "Really skip dead blocks in GVN"
This reverts commit r19779 for breaking the GVN algorithm.
BUG=352149
LOG=y
[email protected]
Committed: https://code.google.com/p/v8/source/detail?r=19932
Please review this at https://codereview.chromium.org/200223004/
SVN Base: https://v8.googlecode.com/svn/branches/bleeding_edge
Affected files (+18, -17 lines):
M src/hydrogen-gvn.cc
Index: src/hydrogen-gvn.cc
diff --git a/src/hydrogen-gvn.cc b/src/hydrogen-gvn.cc
index
827ad271e760f840cb270af632ee374c2d98cdb8..4c98015bee1ef86d9ff7fc2f2c646c4e60e7fd82
100644
--- a/src/hydrogen-gvn.cc
+++ b/src/hydrogen-gvn.cc
@@ -592,9 +592,7 @@ void
HGlobalValueNumberingPhase::LoopInvariantCodeMotion() {
graph()->use_optimistic_licm() ? "yes" : "no");
for (int i = graph()->blocks()->length() - 1; i >= 0; --i) {
HBasicBlock* block = graph()->blocks()->at(i);
- if (block->IsLoopHeader() &&
- block->IsReachable() &&
- !block->IsDeoptimizing()) {
+ if (block->IsLoopHeader()) {
SideEffects side_effects = loop_side_effects_[block->block_id()];
if (FLAG_trace_gvn) {
HeapStringAllocator allocator;
@@ -618,7 +616,6 @@ void HGlobalValueNumberingPhase::ProcessLoopBlock(
HBasicBlock* block,
HBasicBlock* loop_header,
SideEffects loop_kills) {
- if (!block->IsReachable() || block->IsDeoptimizing()) return;
HBasicBlock* pre_header = loop_header->predecessors()->at(0);
if (FLAG_trace_gvn) {
HeapStringAllocator allocator;
@@ -683,8 +680,10 @@ bool HGlobalValueNumberingPhase::AllowCodeMotion() {
bool HGlobalValueNumberingPhase::ShouldMove(HInstruction* instr,
HBasicBlock* loop_header) {
- // If we've disabled code motion, don't move any instructions.
- return AllowCodeMotion();
+ // If we've disabled code motion or we're in a block that unconditionally
+ // deoptimizes, don't move any instructions.
+ return AllowCodeMotion() && !instr->block()->IsDeoptimizing() &&
+ instr->block()->IsReachable();
}
@@ -777,18 +776,20 @@ class GvnBasicBlockState: public ZoneObject {
}
GvnBasicBlockState* next_dominated(Zone* zone) {
- while (++dominated_index_ < length_) {
- HBasicBlock* block =
block_->dominated_blocks()->at(dominated_index_);
- if (block->IsReachable()) {
- if (dominated_index_ == length_ - 1) {
- // No need to copy the map for the last child in the dominator
tree.
- Initialize(block, map(), dominators(), false, zone);
- return this;
- }
- return push(zone, block);
- }
+ dominated_index_++;
+ if (dominated_index_ == length_ - 1) {
+ // No need to copy the map for the last child in the dominator tree.
+ Initialize(block_->dominated_blocks()->at(dominated_index_),
+ map(),
+ dominators(),
+ false,
+ zone);
+ return this;
+ } else if (dominated_index_ < length_) {
+ return push(zone, block_->dominated_blocks()->at(dominated_index_));
+ } else {
+ return NULL;
}
- return NULL;
}
GvnBasicBlockState* push(Zone* zone, HBasicBlock* block) {
--
--
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