Reviewers: Sven,
Description:
Tiny improvement of register constraints in LClassOfTest instructions.
The input register does not need to be made writable. We already
allocate enough temp registers and the input register will always
be preserved.
Please review this at http://codereview.chromium.org/9166007/
SVN Base: http://v8.googlecode.com/svn/branches/bleeding_edge/
Affected files:
M src/arm/lithium-arm.cc
M src/arm/lithium-codegen-arm.cc
M src/ia32/lithium-codegen-ia32.cc
M src/ia32/lithium-ia32.cc
M src/x64/lithium-codegen-x64.cc
M src/x64/lithium-x64.cc
Index: src/arm/lithium-arm.cc
===================================================================
--- src/arm/lithium-arm.cc (revision 10366)
+++ src/arm/lithium-arm.cc (working copy)
@@ -1529,7 +1529,7 @@
LInstruction* LChunkBuilder::DoClassOfTestAndBranch(
HClassOfTestAndBranch* instr) {
ASSERT(instr->value()->representation().IsTagged());
- return new LClassOfTestAndBranch(UseTempRegister(instr->value()),
+ return new LClassOfTestAndBranch(UseRegister(instr->value()),
TempRegister());
}
Index: src/arm/lithium-codegen-arm.cc
===================================================================
--- src/arm/lithium-codegen-arm.cc (revision 10366)
+++ src/arm/lithium-codegen-arm.cc (working copy)
@@ -1994,7 +1994,7 @@
// Branches to a label or falls through with the answer in flags. Trashes
-// the temp registers, but not the input. Only input and temp2 may alias.
+// the temp registers, but not the input.
void LCodeGen::EmitClassOfTest(Label* is_true,
Label* is_false,
Handle<String>class_name,
@@ -2002,7 +2002,9 @@
Register temp,
Register temp2) {
ASSERT(!input.is(temp));
- ASSERT(!temp.is(temp2)); // But input and temp2 may be the same
register.
+ ASSERT(!input.is(temp2));
+ ASSERT(!temp.is(temp2));
+
__ JumpIfSmi(input, is_false);
if (class_name->IsEqualTo(CStrVector("Function"))) {
Index: src/ia32/lithium-codegen-ia32.cc
===================================================================
--- src/ia32/lithium-codegen-ia32.cc (revision 10366)
+++ src/ia32/lithium-codegen-ia32.cc (working copy)
@@ -1831,7 +1831,7 @@
// Branches to a label or falls through with the answer in the z flag.
Trashes
-// the temp registers, but not the input. Only input and temp2 may alias.
+// the temp registers, but not the input.
void LCodeGen::EmitClassOfTest(Label* is_true,
Label* is_false,
Handle<String>class_name,
@@ -1839,7 +1839,8 @@
Register temp,
Register temp2) {
ASSERT(!input.is(temp));
- ASSERT(!temp.is(temp2)); // But input and temp2 may be the same
register.
+ ASSERT(!input.is(temp2));
+ ASSERT(!temp.is(temp2));
__ JumpIfSmi(input, is_false);
if (class_name->IsEqualTo(CStrVector("Function"))) {
@@ -1899,12 +1900,7 @@
Register input = ToRegister(instr->InputAt(0));
Register temp = ToRegister(instr->TempAt(0));
Register temp2 = ToRegister(instr->TempAt(1));
- if (input.is(temp)) {
- // Swap.
- Register swapper = temp;
- temp = temp2;
- temp2 = swapper;
- }
+
Handle<String> class_name = instr->hydrogen()->class_name();
int true_block = chunk_->LookupDestination(instr->true_block_id());
Index: src/ia32/lithium-ia32.cc
===================================================================
--- src/ia32/lithium-ia32.cc (revision 10366)
+++ src/ia32/lithium-ia32.cc (working copy)
@@ -1588,9 +1588,9 @@
LInstruction* LChunkBuilder::DoClassOfTestAndBranch(
HClassOfTestAndBranch* instr) {
ASSERT(instr->value()->representation().IsTagged());
- return new(zone()) LClassOfTestAndBranch(UseTempRegister(instr->value()),
- TempRegister(),
- TempRegister());
+ return new(zone()) LClassOfTestAndBranch(UseRegister(instr->value()),
+ TempRegister(),
+ TempRegister());
}
Index: src/x64/lithium-codegen-x64.cc
===================================================================
--- src/x64/lithium-codegen-x64.cc (revision 10366)
+++ src/x64/lithium-codegen-x64.cc (working copy)
@@ -1755,13 +1755,17 @@
// Branches to a label or falls through with the answer in the z flag.
-// Trashes the temp register and possibly input (if it and temp are
aliased).
+// Trashes the temp register.
void LCodeGen::EmitClassOfTest(Label* is_true,
Label* is_false,
Handle<String> class_name,
Register input,
Register temp,
- Register scratch) {
+ Register temp2) {
+ ASSERT(!input.is(temp));
+ ASSERT(!input.is(temp2));
+ ASSERT(!temp.is(temp2));
+
__ JumpIfSmi(input, is_false);
if (class_name->IsEqualTo(CStrVector("Function"))) {
@@ -1782,9 +1786,9 @@
// Faster code path to avoid two compares: subtract lower bound from
the
// actual type and do a signed compare with the width of the type
range.
__ movq(temp, FieldOperand(input, HeapObject::kMapOffset));
- __ movq(scratch, FieldOperand(temp, Map::kInstanceTypeOffset));
- __ subb(scratch, Immediate(FIRST_NONCALLABLE_SPEC_OBJECT_TYPE));
- __ cmpb(scratch,
+ __ movq(temp2, FieldOperand(temp, Map::kInstanceTypeOffset));
+ __ subb(temp2, Immediate(FIRST_NONCALLABLE_SPEC_OBJECT_TYPE));
+ __ cmpb(temp2,
Immediate(static_cast<int8_t>(LAST_NONCALLABLE_SPEC_OBJECT_TYPE -
FIRST_NONCALLABLE_SPEC_OBJECT_TYPE)));
__ j(above, is_false);
Index: src/x64/lithium-x64.cc
===================================================================
--- src/x64/lithium-x64.cc (revision 10366)
+++ src/x64/lithium-x64.cc (working copy)
@@ -1525,7 +1525,7 @@
LInstruction* LChunkBuilder::DoClassOfTestAndBranch(
HClassOfTestAndBranch* instr) {
- return new LClassOfTestAndBranch(UseTempRegister(instr->value()),
+ return new LClassOfTestAndBranch(UseRegister(instr->value()),
TempRegister(),
TempRegister());
}
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