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MIPS: Fix the hole loading optimization.

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Port r14829 (8fba0f34)

Original commit message:
Fix the hole loading optimization.
- Holes are only ever loaded as double or tagged.
- Change to tagged has to deoptimize on undefined (no implicit   conversions from double the hole NaN -> tagged undefined).

BUG=

Review URL: https://codereview.chromium.org/16116002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@14831 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This commit is contained in:
palfia@homejinni.com 2013-05-27 23:02:27 +00:00
parent 1bdec2bb76
commit 375014a64c
1 changed files with 16 additions and 23 deletions
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39
src/mips/lithium-codegen-mips.cc
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@ -4667,7 +4667,9 @@ void LCodeGen::EmitNumberUntagD(Register input_reg,
Label load_smi, heap_number, done;
if (mode == NUMBER_CANDIDATE_IS_ANY_TAGGED) {
STATIC_ASSERT(NUMBER_CANDIDATE_IS_ANY_TAGGED_CONVERT_HOLE >
NUMBER_CANDIDATE_IS_ANY_TAGGED);
if (mode >= NUMBER_CANDIDATE_IS_ANY_TAGGED) {
// Smi check.
__ UntagAndJumpIfSmi(scratch, input_reg, &load_smi);
@ -4677,13 +4679,18 @@ void LCodeGen::EmitNumberUntagD(Register input_reg,
if (deoptimize_on_undefined) {
DeoptimizeIf(ne, env, scratch, Operand(at));
} else {
Label heap_number;
Label heap_number, convert;
__ Branch(&heap_number, eq, scratch, Operand(at));
// Convert undefined (and hole) to NaN.
__ LoadRoot(at, Heap::kUndefinedValueRootIndex);
if (mode == NUMBER_CANDIDATE_IS_ANY_TAGGED_CONVERT_HOLE) {
__ Branch(&convert, eq, input_reg, Operand(at));
__ LoadRoot(at, Heap::kTheHoleValueRootIndex);
}
DeoptimizeIf(ne, env, input_reg, Operand(at));
// Convert undefined to NaN.
__ bind(&convert);
__ LoadRoot(at, Heap::kNanValueRootIndex);
__ ldc1(result_reg, FieldMemOperand(at, HeapNumber::kValueOffset));
__ Branch(&done);
@ -4699,14 +4706,6 @@ void LCodeGen::EmitNumberUntagD(Register input_reg,
DeoptimizeIf(eq, env, scratch, Operand(HeapNumber::kSignMask));
}
__ Branch(&done);
} else if (mode == NUMBER_CANDIDATE_IS_SMI_OR_HOLE) {
__ SmiUntag(scratch, input_reg);
DeoptimizeIf(Ugreater_equal, env, scratch, Operand(zero_reg));
} else if (mode == NUMBER_CANDIDATE_IS_SMI_CONVERT_HOLE) {
__ UntagAndJumpIfSmi(scratch, input_reg, &load_smi);
__ Move(result_reg,
FixedDoubleArray::hole_nan_as_double());
__ Branch(&done);
} else {
__ SmiUntag(scratch, input_reg);
ASSERT(mode == NUMBER_CANDIDATE_IS_SMI);
@ -4839,19 +4838,13 @@ void LCodeGen::DoNumberUntagD(LNumberUntagD* instr) {
NumberUntagDMode mode = NUMBER_CANDIDATE_IS_ANY_TAGGED;
HValue* value = instr->hydrogen()->value();
if (value->type().IsSmi()) {
if (value->IsLoadKeyed()) {
HLoadKeyed* load = HLoadKeyed::cast(value);
if (load->UsesMustHandleHole()) {
if (load->hole_mode() == ALLOW_RETURN_HOLE) {
mode = NUMBER_CANDIDATE_IS_SMI_CONVERT_HOLE;
} else {
mode = NUMBER_CANDIDATE_IS_SMI_OR_HOLE;
}
} else {
mode = NUMBER_CANDIDATE_IS_SMI;
mode = NUMBER_CANDIDATE_IS_SMI;
} else if (value->IsLoadKeyed()) {
HLoadKeyed* load = HLoadKeyed::cast(value);
if (load->UsesMustHandleHole()) {
if (load->hole_mode() == ALLOW_RETURN_HOLE) {
mode = NUMBER_CANDIDATE_IS_ANY_TAGGED_CONVERT_HOLE;
}
} else {
mode = NUMBER_CANDIDATE_IS_SMI;
}
}