Reviewers: Sven Panne,
Message:
Next baby step in GVN change... these flags are collected during LICM, but
never
used afterwards. PTAL
Description:
Drop unused accumulated first time changes/depends.
Please review this at https://codereview.chromium.org/135503004/
SVN Base: https://v8.googlecode.com/svn/branches/bleeding_edge
Affected files (+3, -29 lines):
M src/hydrogen-gvn.h
M src/hydrogen-gvn.cc
Index: src/hydrogen-gvn.cc
diff --git a/src/hydrogen-gvn.cc b/src/hydrogen-gvn.cc
index
e491ef5b98cb9c0424d5502a84c79174587425cd..bc836890bb136544c560474c222d7b354c9ddb4a
100644
--- a/src/hydrogen-gvn.cc
+++ b/src/hydrogen-gvn.cc
@@ -535,13 +535,9 @@ void
HGlobalValueNumberingPhase::LoopInvariantCodeMotion() {
block->block_id(),
GetGVNFlagsString(side_effects).get());
- GVNFlagSet accumulated_first_time_depends;
- GVNFlagSet accumulated_first_time_changes;
HBasicBlock* last = block->loop_information()->GetLastBackEdge();
for (int j = block->block_id(); j <= last->block_id(); ++j) {
- ProcessLoopBlock(graph()->blocks()->at(j), block, side_effects,
- &accumulated_first_time_depends,
- &accumulated_first_time_changes);
+ ProcessLoopBlock(graph()->blocks()->at(j), block, side_effects);
}
}
}
@@ -551,9 +547,7 @@ void
HGlobalValueNumberingPhase::LoopInvariantCodeMotion() {
void HGlobalValueNumberingPhase::ProcessLoopBlock(
HBasicBlock* block,
HBasicBlock* loop_header,
- GVNFlagSet loop_kills,
- GVNFlagSet* first_time_depends,
- GVNFlagSet* first_time_changes) {
+ GVNFlagSet loop_kills) {
HBasicBlock* pre_header = loop_header->predecessors()->at(0);
GVNFlagSet depends_flags =
HValue::ConvertChangesToDependsFlags(loop_kills);
TRACE_GVN_2("Loop invariant motion for B%d %s\n",
@@ -562,7 +556,6 @@ void HGlobalValueNumberingPhase::ProcessLoopBlock(
HInstruction* instr = block->first();
while (instr != NULL) {
HInstruction* next = instr->next();
- bool hoisted = false;
if (instr->CheckFlag(HValue::kUseGVN)) {
TRACE_GVN_4("Checking instruction %d (%s) %s. Loop %s\n",
instr->id(),
@@ -589,26 +582,9 @@ void HGlobalValueNumberingPhase::ProcessLoopBlock(
instr->Unlink();
instr->InsertBefore(pre_header->end());
if (instr->HasSideEffects()) removed_side_effects_ = true;
- hoisted = true;
}
}
}
- if (!hoisted) {
- // If an instruction is not hoisted, we have to account for its side
- // effects when hoisting later HTransitionElementsKind instructions.
- GVNFlagSet previous_depends = *first_time_depends;
- GVNFlagSet previous_changes = *first_time_changes;
- first_time_depends->Add(instr->DependsOnFlags());
- first_time_changes->Add(instr->ChangesFlags());
- if (!(previous_depends == *first_time_depends)) {
- TRACE_GVN_1("Updated first-time accumulated %s\n",
- GetGVNFlagsString(*first_time_depends).get());
- }
- if (!(previous_changes == *first_time_changes)) {
- TRACE_GVN_1("Updated first-time accumulated %s\n",
- GetGVNFlagsString(*first_time_changes).get());
- }
- }
instr = next;
}
}
Index: src/hydrogen-gvn.h
diff --git a/src/hydrogen-gvn.h b/src/hydrogen-gvn.h
index
4e4f349adc2f9929f8e11361ff4de7ba0384379a..30333cca61045d7292496cece8aa3235c173e7fb
100644
--- a/src/hydrogen-gvn.h
+++ b/src/hydrogen-gvn.h
@@ -52,9 +52,7 @@ class HGlobalValueNumberingPhase : public HPhase {
void LoopInvariantCodeMotion();
void ProcessLoopBlock(HBasicBlock* block,
HBasicBlock* before_loop,
- GVNFlagSet loop_kills,
- GVNFlagSet* accumulated_first_time_depends,
- GVNFlagSet* accumulated_first_time_changes);
+ GVNFlagSet loop_kills);
bool AllowCodeMotion();
bool ShouldMove(HInstruction* instr, HBasicBlock* loop_header);
--
--
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