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Unified Diff: src/x64/lithium-codegen-x64.cc

Issue 7489045: ARM: Fast path for compare against constant. (Closed) Base URL: http://v8.googlecode.com/svn/branches/bleeding_edge/
Patch Set: '' Created 9 years, 3 months ago
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Index: src/x64/lithium-codegen-x64.cc
===================================================================
--- src/x64/lithium-codegen-x64.cc (revision 9243)
+++ src/x64/lithium-codegen-x64.cc (working copy)
@@ -368,6 +368,12 @@
}
+double LCodeGen::ToDouble(LConstantOperand* op) const {
+ Handle<Object> value = chunk_->LookupLiteral(op);
+ return value->Number();
+}
+
+
Handle<Object> LCodeGen::ToHandle(LConstantOperand* op) const {
Handle<Object> literal = chunk_->LookupLiteral(op);
ASSERT(chunk_->LookupLiteralRepresentation(op).IsTagged());
@@ -1520,39 +1526,47 @@
}
-void LCodeGen::EmitCmpI(LOperand* left, LOperand* right) {
- if (right->IsConstantOperand()) {
- int32_t value = ToInteger32(LConstantOperand::cast(right));
- if (left->IsRegister()) {
- __ cmpl(ToRegister(left), Immediate(value));
- } else {
- __ cmpl(ToOperand(left), Immediate(value));
- }
- } else if (right->IsRegister()) {
- __ cmpl(ToRegister(left), ToRegister(right));
- } else {
- __ cmpl(ToRegister(left), ToOperand(right));
- }
-}
-
-
void LCodeGen::DoCmpIDAndBranch(LCmpIDAndBranch* instr) {
LOperand* left = instr->InputAt(0);
LOperand* right = instr->InputAt(1);
int false_block = chunk_->LookupDestination(instr->false_block_id());
int true_block = chunk_->LookupDestination(instr->true_block_id());
+ Condition cc = TokenToCondition(instr->op(), instr->is_double());
- if (instr->is_double()) {
- // Don't base result on EFLAGS when a NaN is involved. Instead
- // jump to the false block.
- __ ucomisd(ToDoubleRegister(left), ToDoubleRegister(right));
- __ j(parity_even, chunk_->GetAssemblyLabel(false_block));
+ if (left->IsConstantOperand() && right->IsConstantOperand()) {
+ // We can statically evaluate the comparison.
+ double left_val = ToDouble(LConstantOperand::cast(left));
+ double right_val = ToDouble(LConstantOperand::cast(right));
+ int next_block =
+ EvalComparison(instr->op(), left_val, right_val) ? true_block
+ : false_block;
+ EmitGoto(next_block);
} else {
- EmitCmpI(left, right);
+ if (instr->is_double()) {
+ // Don't base result on EFLAGS when a NaN is involved. Instead
+ // jump to the false block.
+ __ ucomisd(ToDoubleRegister(left), ToDoubleRegister(right));
+ __ j(parity_even, chunk_->GetAssemblyLabel(false_block));
+ } else {
+ int32_t value;
+ if (right->IsConstantOperand()) {
+ value = ToInteger32(LConstantOperand::cast(right));
+ __ cmpl(ToRegister(left), Immediate(value));
+ } else if (left->IsConstantOperand()) {
+ value = ToInteger32(LConstantOperand::cast(left));
+ if (right->IsRegister()) {
+ __ cmpl(ToRegister(right), Immediate(value));
+ } else {
+ __ cmpl(ToOperand(right), Immediate(value));
+ }
+ // We transposed the operands. Reverse the condition.
+ cc = ReverseCondition(cc);
+ } else {
+ __ cmpl(ToRegister(left), ToOperand(right));
William Hesse 2011/10/20 10:28:40 The register and memory operand cases for right mu
+ }
+ }
+ EmitBranch(true_block, false_block, cc);
}
-
- Condition cc = TokenToCondition(instr->op(), instr->is_double());
- EmitBranch(true_block, false_block, cc);
}

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