Revision: 19779
Author: [email protected]
Date: Tue Mar 11 08:14:38 2014 UTC
Log: Really skip dead blocks in GVN
[email protected]
Review URL: https://codereview.chromium.org/194413002
http://code.google.com/p/v8/source/detail?r=19779
Modified:
/branches/bleeding_edge/src/hydrogen-gvn.cc
=======================================
--- /branches/bleeding_edge/src/hydrogen-gvn.cc Fri Mar 7 10:14:03 2014 UTC
+++ /branches/bleeding_edge/src/hydrogen-gvn.cc Tue Mar 11 08:14:38 2014 UTC
@@ -592,7 +592,9 @@
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()) {
+ if (block->IsLoopHeader() &&
+ block->IsReachable() &&
+ !block->IsDeoptimizing()) {
SideEffects side_effects = loop_side_effects_[block->block_id()];
if (FLAG_trace_gvn) {
HeapStringAllocator allocator;
@@ -616,6 +618,7 @@
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;
@@ -680,10 +683,8 @@
bool HGlobalValueNumberingPhase::ShouldMove(HInstruction* instr,
HBasicBlock* loop_header) {
- // 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();
+ // If we've disabled code motion, don't move any instructions.
+ return AllowCodeMotion();
}
@@ -776,20 +777,18 @@
}
GvnBasicBlockState* next_dominated(Zone* zone) {
- 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;
+ 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);
+ }
}
+ return NULL;
}
GvnBasicBlockState* push(Zone* zone, HBasicBlock* block) {
--
--
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