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Only set binary operation side effects flags, when observable.

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BUG=
R=verwaest@chromium.org

Review URL: https://codereview.chromium.org/26712002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@17147 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This commit is contained in:
olivf@chromium.org 2013-10-10 16:49:25 +00:00
parent 907f079d25
commit 4b6d0e33f2
2 changed files with 41 additions and 9 deletions
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37
src/hydrogen-instructions.h
View File

@ -3947,11 +3947,12 @@ class HBitwiseBinaryOperation : public HBinaryOperation {
}
virtual void RepresentationChanged(Representation to) V8_OVERRIDE {
if (to.IsTagged()) {
if (to.IsTagged()) SetGVNFlag(kChangesNewSpacePromotion);
if (to.IsTagged() &&
(left()->ToNumberCanBeObserved() || right()->ToNumberCanBeObserved())) {
SetAllSideEffects();
ClearFlag(kUseGVN);
} else {
ASSERT(to.IsSmiOrInteger32());
ClearAllSideEffects();
SetFlag(kUseGVN);
}
@ -4023,7 +4024,9 @@ class HArithmeticBinaryOperation : public HBinaryOperation {
}
virtual void RepresentationChanged(Representation to) V8_OVERRIDE {
if (to.IsTagged()) {
if (to.IsTagged()) SetGVNFlag(kChangesNewSpacePromotion);
if (to.IsTagged() &&
(left()->ToNumberCanBeObserved() || right()->ToNumberCanBeObserved())) {
SetAllSideEffects();
ClearFlag(kUseGVN);
} else {
@ -4562,8 +4565,19 @@ class HAdd V8_FINAL : public HArithmeticBinaryOperation {
}
virtual void RepresentationChanged(Representation to) V8_OVERRIDE {
if (to.IsTagged()) ClearFlag(kAllowUndefinedAsNaN);
HArithmeticBinaryOperation::RepresentationChanged(to);
if (to.IsTagged()) {
SetGVNFlag(kChangesNewSpacePromotion);
ClearFlag(kAllowUndefinedAsNaN);
}
if (to.IsTagged() &&
(left()->ToNumberCanBeObserved() || right()->ToNumberCanBeObserved() ||
left()->ToStringCanBeObserved() || right()->ToStringCanBeObserved())) {
SetAllSideEffects();
ClearFlag(kUseGVN);
} else {
ClearAllSideEffects();
SetFlag(kUseGVN);
}
}
DECLARE_CONCRETE_INSTRUCTION(Add)
@ -6632,20 +6646,25 @@ class HStringAdd V8_FINAL : public HBinaryOperation {
HStringAdd(HValue* context, HValue* left, HValue* right, StringAddFlags flags)
: HBinaryOperation(context, left, right, HType::String()), flags_(flags) {
set_representation(Representation::Tagged());
if (flags_ == STRING_ADD_CHECK_NONE) {
if (MightHaveSideEffects()) {
SetAllSideEffects();
} else {
SetFlag(kUseGVN);
SetGVNFlag(kDependsOnMaps);
SetGVNFlag(kChangesNewSpacePromotion);
} else {
SetAllSideEffects();
}
}
bool MightHaveSideEffects() const {
return flags_ != STRING_ADD_CHECK_NONE &&
(left()->ToStringCanBeObserved() || right()->ToStringCanBeObserved());
}
// No side-effects except possible allocation:
// NOTE: this instruction does not call ToString() on its inputs, when flags_
// is set to STRING_ADD_CHECK_NONE.
virtual bool IsDeletable() const V8_OVERRIDE {
return flags_ == STRING_ADD_CHECK_NONE;
return !MightHaveSideEffects();
}
const StringAddFlags flags_;

13
test/mjsunit/regress/regress-binop.js
View File

@ -166,3 +166,16 @@ assertEquals(t2(undefined,2), NaN/2);
assertEquals(t2(1,1<<30), 1/(1<<30));
assertEquals(t2(1,2), 1/2);
// Assert that the hole is not truncated to nan for string add.
function string_add(a,i) {
var d = [0.1, ,0.3];
return a + d[i];
}
string_add(1.1, 0);
string_add("", 0);
%OptimizeFunctionOnNextCall(string_add);
string_add(1.1, 0);
// There comes the hole
assertEquals("undefined", string_add("", 1));