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Avoid creating unnecessary branches in Hydrogen

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Review URL: https://codereview.chromium.org/12281019

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13704 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This commit is contained in:
jkummerow@chromium.org 2013-02-21 11:29:51 +00:00
parent 8ef28eb5ee
commit e93011892e
2 changed files with 29 additions and 9 deletions
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9
src/hydrogen-instructions.cc
View File

@ -2784,11 +2784,9 @@ bool HStoreKeyed::NeedsCanonicalization() {
#define H_CONSTANT_INT32(val) \
new(zone) HConstant(FACTORY->NewNumberFromInt(val, TENURED), \
Representation::Integer32())
new(zone) HConstant(val, Representation::Integer32())
#define H_CONSTANT_DOUBLE(val) \
new(zone) HConstant(FACTORY->NewNumber(val, TENURED), \
Representation::Double())
new(zone) HConstant(val, Representation::Double())
#define DEFINE_NEW_H_SIMPLE_ARITHMETIC_INSTR(HInstr, op) \
HInstruction* HInstr::New##HInstr(Zone* zone, \
@ -2933,7 +2931,8 @@ HInstruction* HShr::NewHShr(Zone* zone,
return H_CONSTANT_DOUBLE(
static_cast<double>(static_cast<uint32_t>(left_val)));
}
return H_CONSTANT_INT32(static_cast<uint32_t>(left_val) >> right_val);
return H_CONSTANT_INT32(static_cast<int32_t>(
static_cast<uint32_t>(left_val) >> right_val));
}
}
return new(zone) HShr(context, left, right);

29
src/hydrogen.cc
View File

@ -3620,6 +3620,16 @@ void TestContext::BuildBranch(HValue* value) {
if (value != NULL && value->CheckFlag(HValue::kIsArguments)) {
builder->Bailout("arguments object value in a test context");
}
if (value->IsConstant()) {
HConstant* constant_value = HConstant::cast(value);
if (constant_value->ToBoolean()) {
builder->current_block()->Goto(if_true(), builder->function_state());
} else {
builder->current_block()->Goto(if_false(), builder->function_state());
}
builder->set_current_block(NULL);
return;
}
HBasicBlock* empty_true = builder->graph()->CreateBasicBlock();
HBasicBlock* empty_false = builder->graph()->CreateBasicBlock();
TypeFeedbackId test_id = condition()->test_id();
@ -3627,8 +3637,8 @@ void TestContext::BuildBranch(HValue* value) {
HBranch* test = new(zone()) HBranch(value, empty_true, empty_false, expected);
builder->current_block()->Finish(test);
empty_true->Goto(if_true(), owner()->function_state());
empty_false->Goto(if_false(), owner()->function_state());
empty_true->Goto(if_true(), builder->function_state());
empty_false->Goto(if_false(), builder->function_state());
builder->set_current_block(NULL);
}
@ -9037,6 +9047,17 @@ void HOptimizedGraphBuilder::VisitLogicalExpression(BinaryOperation* expr) {
} else if (ast_context()->IsValue()) {
CHECK_ALIVE(VisitForValue(expr->left()));
ASSERT(current_block() != NULL);
HValue* left_value = Top();
if (left_value->IsConstant()) {
HConstant* left_constant = HConstant::cast(left_value);
if ((is_logical_and && left_constant->ToBoolean()) ||
(!is_logical_and && !left_constant->ToBoolean())) {
Drop(1); // left_value.
CHECK_BAILOUT(VisitForValue(expr->right()));
}
return ast_context()->ReturnValue(Pop());
}
// We need an extra block to maintain edge-split form.
HBasicBlock* empty_block = graph()->CreateBasicBlock();
@ -9044,8 +9065,8 @@ void HOptimizedGraphBuilder::VisitLogicalExpression(BinaryOperation* expr) {
TypeFeedbackId test_id = expr->left()->test_id();
ToBooleanStub::Types expected(oracle()->ToBooleanTypes(test_id));
HBranch* test = is_logical_and
? new(zone()) HBranch(Top(), eval_right, empty_block, expected)
: new(zone()) HBranch(Top(), empty_block, eval_right, expected);
? new(zone()) HBranch(left_value, eval_right, empty_block, expected)
: new(zone()) HBranch(left_value, empty_block, eval_right, expected);
current_block()->Finish(test);
set_current_block(eval_right);