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Add roundsd instruction to ia32 and use it in optimized Math.floor.

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It is available platforms that have SSE 4.1 and allows us to handle
negative numbers without deoptimization. Before we would deoptimize
on negative inputs to Math.floor. x64 already uses this instruction.

* Change Math.floor unit test to make sure every test case gets
optimized by changing the source code for each test case.

* Fix HIR debug printing for some instructions.
Review URL: http://codereview.chromium.org/7628017

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@8921 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This commit is contained in:
fschneider@chromium.org 2011-08-12 10:13:40 +00:00
parent b814d6b099
commit 6549163a55
8 changed files with 106 additions and 31 deletions
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20
src/hydrogen-instructions.cc
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@ -635,6 +635,12 @@ void HBinaryCall::PrintDataTo(StringStream* stream) {
}
void HBoundsCheck::PrintDataTo(StringStream* stream) {
index()->PrintNameTo(stream);
stream->Add(" ");
length()->PrintNameTo(stream);
}
void HCallConstantFunction::PrintDataTo(StringStream* stream) {
if (IsApplyFunction()) {
stream->Add("optimized apply ");
@ -1364,6 +1370,20 @@ bool HLoadNamedFieldPolymorphic::DataEquals(HValue* value) {
}
void HLoadNamedFieldPolymorphic::PrintDataTo(StringStream* stream) {
object()->PrintNameTo(stream);
stream->Add(" .");
stream->Add(*String::cast(*name())->ToCString());
}
void HLoadNamedGeneric::PrintDataTo(StringStream* stream) {
object()->PrintNameTo(stream);
stream->Add(" .");
stream->Add(*String::cast(*name())->ToCString());
}
void HLoadKeyedFastElement::PrintDataTo(StringStream* stream) {
object()->PrintNameTo(stream);
stream->Add("[");

6
src/hydrogen-instructions.h
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@ -2449,6 +2449,8 @@ class HBoundsCheck: public HTemplateInstruction<2> {
return Representation::Integer32();
}
virtual void PrintDataTo(StringStream* stream);
HValue* index() { return OperandAt(0); }
HValue* length() { return OperandAt(1); }
@ -3416,6 +3418,8 @@ class HLoadNamedFieldPolymorphic: public HTemplateInstruction<2> {
return Representation::Tagged();
}
virtual void PrintDataTo(StringStream* stream);
DECLARE_CONCRETE_INSTRUCTION(LoadNamedFieldPolymorphic)
static const int kMaxLoadPolymorphism = 4;
@ -3449,6 +3453,8 @@ class HLoadNamedGeneric: public HTemplateInstruction<2> {
return Representation::Tagged();
}
virtual void PrintDataTo(StringStream* stream);
DECLARE_CONCRETE_INSTRUCTION(LoadNamedGeneric)
private:

12
src/ia32/assembler-ia32.cc
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@ -1957,6 +1957,18 @@ void Assembler::ucomisd(XMMRegister dst, XMMRegister src) {
}
void Assembler::roundsd(XMMRegister dst, XMMRegister src, RoundingMode mode) {
ASSERT(CpuFeatures::IsEnabled(SSE4_1));
EnsureSpace ensure_space(this);
EMIT(0x66);
EMIT(0x0F);
EMIT(0x3A);
EMIT(0x0B);
emit_sse_operand(dst, src);
// Mask precision exeption.
EMIT(static_cast<byte>(mode) | 0x8);
}
void Assembler::movmskpd(Register dst, XMMRegister src) {
ASSERT(CpuFeatures::IsEnabled(SSE2));
EnsureSpace ensure_space(this);

10
src/ia32/assembler-ia32.h
View File

@ -941,6 +941,16 @@ class Assembler : public AssemblerBase {
void andpd(XMMRegister dst, XMMRegister src);
void ucomisd(XMMRegister dst, XMMRegister src);
enum RoundingMode {
kRoundToNearest = 0x0,
kRoundDown = 0x1,
kRoundUp = 0x2,
kRoundToZero = 0x3
};
void roundsd(XMMRegister dst, XMMRegister src, RoundingMode mode);
void movmskpd(Register dst, XMMRegister src);
void cmpltsd(XMMRegister dst, XMMRegister src);

12
src/ia32/disasm-ia32.cc
View File

@ -1141,7 +1141,17 @@ int DisassemblerIA32::InstructionDecode(v8::internal::Vector<char> out_buffer,
}
} else if (*data == 0x3A) {
data++;
if (*data == 0x16) {
if (*data == 0x0B) {
data++;
int mod, regop, rm;
get_modrm(*data, &mod, &regop, &rm);
int8_t imm8 = static_cast<int8_t>(data[1]);
AppendToBuffer("roundsd %s,%s,%d",
NameOfXMMRegister(regop),
NameOfXMMRegister(rm),
static_cast<int>(imm8));
data += 2;
} else if (*data == 0x16) {
data++;
int mod, regop, rm;
get_modrm(*data, &mod, &regop, &rm);

1
src/ia32/full-codegen-ia32.cc
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@ -3830,7 +3830,6 @@ void FullCodeGenerator::VisitUnaryOperation(UnaryOperation* expr) {
void FullCodeGenerator::EmitUnaryOperation(UnaryOperation* expr,
const char* comment) {
// TODO(svenpanne): Allowing format strings in Comment would be nice here...
Comment cmt(masm_, comment);
bool can_overwrite = expr->expression()->ResultOverwriteAllowed();
UnaryOverwriteMode overwrite =

69
src/ia32/lithium-codegen-ia32.cc
View File

@ -2713,35 +2713,54 @@ void LCodeGen::DoMathFloor(LUnaryMathOperation* instr) {
XMMRegister xmm_scratch = xmm0;
Register output_reg = ToRegister(instr->result());
XMMRegister input_reg = ToDoubleRegister(instr->value());
Label done;
// Deoptimize on negative numbers.
__ xorps(xmm_scratch, xmm_scratch); // Zero the register.
__ ucomisd(input_reg, xmm_scratch);
DeoptimizeIf(below, instr->environment());
if (CpuFeatures::IsSupported(SSE4_1)) {
CpuFeatures::Scope scope(SSE4_1);
if (instr->hydrogen()->CheckFlag(HValue::kBailoutOnMinusZero)) {
// Deoptimize on negative zero.
Label non_zero;
__ xorps(xmm_scratch, xmm_scratch); // Zero the register.
__ ucomisd(input_reg, xmm_scratch);
__ j(not_equal, &non_zero, Label::kNear);
__ movmskpd(output_reg, input_reg);
__ test(output_reg, Immediate(1));
DeoptimizeIf(not_zero, instr->environment());
__ bind(&non_zero);
}
__ roundsd(xmm_scratch, input_reg, Assembler::kRoundDown);
__ cvttsd2si(output_reg, Operand(xmm_scratch));
// Overflow is signalled with minint.
__ cmp(output_reg, 0x80000000u);
DeoptimizeIf(equal, instr->environment());
} else {
Label done;
// Deoptimize on negative numbers.
__ xorps(xmm_scratch, xmm_scratch); // Zero the register.
__ ucomisd(input_reg, xmm_scratch);
DeoptimizeIf(below, instr->environment());
if (instr->hydrogen()->CheckFlag(HValue::kBailoutOnMinusZero)) {
// Check for negative zero.
Label positive_sign;
__ j(above, &positive_sign, Label::kNear);
__ movmskpd(output_reg, input_reg);
__ test(output_reg, Immediate(1));
DeoptimizeIf(not_zero, instr->environment());
__ Set(output_reg, Immediate(0));
__ jmp(&done, Label::kNear);
__ bind(&positive_sign);
if (instr->hydrogen()->CheckFlag(HValue::kBailoutOnMinusZero)) {
// Check for negative zero.
Label positive_sign;
__ j(above, &positive_sign, Label::kNear);
__ movmskpd(output_reg, input_reg);
__ test(output_reg, Immediate(1));
DeoptimizeIf(not_zero, instr->environment());
__ Set(output_reg, Immediate(0));
__ jmp(&done, Label::kNear);
__ bind(&positive_sign);
}
// Use truncating instruction (OK because input is positive).
__ cvttsd2si(output_reg, Operand(input_reg));
// Overflow is signalled with minint.
__ cmp(output_reg, 0x80000000u);
DeoptimizeIf(equal, instr->environment());
__ bind(&done);
}
// Use truncating instruction (OK because input is positive).
__ cvttsd2si(output_reg, Operand(input_reg));
// Overflow is signalled with minint.
__ cmp(output_reg, 0x80000000u);
DeoptimizeIf(equal, instr->environment());
__ bind(&done);
}
void LCodeGen::DoMathRound(LUnaryMathOperation* instr) {
XMMRegister xmm_scratch = xmm0;
Register output_reg = ToRegister(instr->result());
@ -2751,13 +2770,11 @@ void LCodeGen::DoMathRound(LUnaryMathOperation* instr) {
// xmm_scratch = 0.5
ExternalReference one_half = ExternalReference::address_of_one_half();
__ movdbl(xmm_scratch, Operand::StaticVariable(one_half));
__ ucomisd(xmm_scratch, input_reg);
__ j(above, &below_half);
// input = input + 0.5
__ addsd(input_reg, xmm_scratch);
// Compute Math.floor(value + 0.5).
// Use truncating instruction (OK because input is positive).
__ cvttsd2si(output_reg, Operand(input_reg));

7
test/mjsunit/math-floor.js
View File

@ -27,10 +27,11 @@
// Flags: --max-new-space-size=256 --allow-natives-syntax
var test_id = 0;
function testFloor(expect, input) {
function test(n) {
return Math.floor(n);
}
var test = new Function('n',
'"' + (test_id++) + '";return Math.floor(n)');
assertEquals(expect, test(input));
assertEquals(expect, test(input));
assertEquals(expect, test(input));