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Eliminate HCheckHeapObject instructions in check elimination.

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BUG=
R=verwaest@chromium.org

Review URL: https://codereview.chromium.org/95263005

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@18160 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This commit is contained in:
titzer@chromium.org 2013-11-29 12:37:35 +00:00
parent e5eef90e76
commit 425f3fde00
2 changed files with 28 additions and 9 deletions
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35
src/hydrogen-check-elimination.cc
View File

@ -97,6 +97,10 @@ class HCheckTable : public ZoneObject {
ReduceCheckMapValue(HCheckMapValue::cast(instr));
break;
}
case HValue::kCheckHeapObject: {
ReduceCheckHeapObject(HCheckHeapObject::cast(instr));
break;
}
default: {
// If the instruction changes maps uncontrollably, drop everything.
if (instr->CheckGVNFlag(kChangesMaps) ||
@ -105,7 +109,8 @@ class HCheckTable : public ZoneObject {
}
}
// Improvements possible:
// - eliminate HCheckSmi and HCheckHeapObject
// - eliminate redundant HCheckSmi, HCheckInstanceType instructions
// - track which values have been HCheckHeapObject'd
}
return this;
@ -236,6 +241,14 @@ class HCheckTable : public ZoneObject {
}
}
void ReduceCheckHeapObject(HCheckHeapObject* instr) {
if (FindMaps(instr->value()->ActualValue()) != NULL) {
// If the object has known maps, it's definitely a heap object.
instr->DeleteAndReplaceWith(instr->value());
INC_STAT(removed_cho_);
}
}
void ReduceStoreNamedField(HStoreNamedField* instr) {
HValue* object = instr->object()->ActualValue();
if (instr->has_transition()) {
@ -488,15 +501,19 @@ void HCheckEliminationPhase::Run() {
// Are we eliminated yet?
void HCheckEliminationPhase::PrintStats() {
#if DEBUG
if (redundant_ > 0) PrintF(" redundant = %2d\n", redundant_);
if (removed_ > 0) PrintF(" removed = %2d\n", removed_);
if (narrowed_ > 0) PrintF(" narrowed = %2d\n", narrowed_);
if (loads_ > 0) PrintF(" loads = %2d\n", loads_);
if (empty_ > 0) PrintF(" empty = %2d\n", empty_);
if (compares_true_ > 0) PrintF(" cmp_true = %2d\n", compares_true_);
if (compares_false_ > 0) PrintF(" cmp_false = %2d\n", compares_false_);
if (transitions_ > 0) PrintF(" transitions = %2d\n", transitions_);
#define PRINT_STAT(x) if (x##_ > 0) PrintF(" %-16s = %2d\n", #x, x##_)
#else
#define PRINT_STAT(x)
#endif
PRINT_STAT(redundant);
PRINT_STAT(removed);
PRINT_STAT(removed_cho);
PRINT_STAT(narrowed);
PRINT_STAT(loads);
PRINT_STAT(empty);
PRINT_STAT(compares_true);
PRINT_STAT(compares_false);
PRINT_STAT(transitions);
}
} } // namespace v8::internal

2
src/hydrogen-check-elimination.h
View File

@ -43,6 +43,7 @@ class HCheckEliminationPhase : public HPhase {
aliasing_(),
redundant_(0),
removed_(0),
removed_cho_(0),
narrowed_(0),
loads_(0),
empty_(0),
@ -60,6 +61,7 @@ class HCheckEliminationPhase : public HPhase {
HAliasAnalyzer* aliasing_;
int redundant_;
int removed_;
int removed_cho_;
int narrowed_;
int loads_;
int empty_;