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Bug 1042823 - Don't blindly make MMinMax optimize for doubles, r=jandem,sunfish

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This commit is contained in:
Hannes Verschore 2014-10-22 22:12:45 +02:00
parent 477e00b11f
commit a1e41d89c8
4 changed files with 149 additions and 13 deletions
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2
js/src/builtin/Utilities.js
View File

@ -100,7 +100,7 @@ function ToLength(v) {
return 0;
// Math.pow(2, 53) - 1 = 0x1fffffffffffff
return v < 0x1fffffffffffff ? v : 0x1fffffffffffff;
return std_Math_min(v, 0x1fffffffffffff);
}
/********** Testing code **********/

51
js/src/jit/MCallOptimize.cpp
View File

@ -1147,31 +1147,64 @@ IonBuilder::inlineMathFRound(CallInfo &callInfo)
IonBuilder::InliningStatus
IonBuilder::inlineMathMinMax(CallInfo &callInfo, bool max)
{
if (callInfo.argc() < 2 || callInfo.constructing())
if (callInfo.argc() < 1 || callInfo.constructing())
return InliningStatus_NotInlined;
MIRType returnType = getInlineReturnType();
if (!IsNumberType(returnType))
return InliningStatus_NotInlined;
MDefinitionVector int32_cases(alloc());
for (unsigned i = 0; i < callInfo.argc(); i++) {
MIRType argType = callInfo.getArg(i)->type();
if (!IsNumberType(argType))
return InliningStatus_NotInlined;
MDefinition *arg = callInfo.getArg(i);
// When one of the arguments is double, do a double MMinMax.
if (returnType == MIRType_Int32 && IsFloatingPointType(argType))
switch (arg->type()) {
case MIRType_Int32:
if (!int32_cases.append(arg))
return InliningStatus_Error;
break;
case MIRType_Double:
case MIRType_Float32:
// Don't force a double MMinMax for arguments that would be a NOP
// when doing an integer MMinMax.
if (arg->isConstant()) {
double cte = arg->toConstant()->value().toDouble();
// min(int32, cte >= INT32_MAX) = int32
if (cte >= INT32_MAX && !max)
break;
// max(int32, cte <= INT32_MIN) = int32
if (cte <= INT32_MIN && max)
break;
}
// Force double MMinMax if argument is a "effectfull" double.
returnType = MIRType_Double;
break;
default:
return InliningStatus_NotInlined;
}
}
if (int32_cases.length() == 0)
returnType = MIRType_Double;
callInfo.setImplicitlyUsedUnchecked();
MDefinitionVector &cases = (returnType == MIRType_Int32) ? int32_cases : callInfo.argv();
if (cases.length() == 1) {
MLimitedTruncate *limit = MLimitedTruncate::New(alloc(), cases[0], MDefinition::NoTruncate);
current->add(limit);
current->push(limit);
return InliningStatus_Inlined;
}
// Chain N-1 MMinMax instructions to compute the MinMax.
MMinMax *last = MMinMax::New(alloc(), callInfo.getArg(0), callInfo.getArg(1), returnType, max);
MMinMax *last = MMinMax::New(alloc(), cases[0], cases[1], returnType, max);
current->add(last);
for (unsigned i = 2; i < callInfo.argc(); i++) {
MMinMax *ins = MMinMax::New(alloc(), last, callInfo.getArg(i), returnType, max);
for (unsigned i = 2; i < cases.length(); i++) {
MMinMax *ins = MMinMax::New(alloc(), last, cases[2], returnType, max);
current->add(ins);
last = ins;
}

106
js/src/jit/MIR.cpp
View File

@ -1830,6 +1830,41 @@ MMinMax::trySpecializeFloat32(TempAllocator &alloc)
setResultType(MIRType_Float32);
}
MDefinition *
MMinMax::foldsTo(TempAllocator &alloc)
{
if (!lhs()->isConstant() && !rhs()->isConstant())
return this;
MDefinition *operand = lhs()->isConstant() ? rhs() : lhs();
MConstant *constant = lhs()->isConstant() ? lhs()->toConstant() : rhs()->toConstant();
if (operand->isToDouble() && operand->getOperand(0)->type() == MIRType_Int32) {
const js::Value &val = constant->value();
// min(int32, cte >= INT32_MAX) = int32
if (val.isDouble() && val.toDouble() >= INT32_MAX && !isMax()) {
MLimitedTruncate *limit =
MLimitedTruncate::New(alloc, operand->getOperand(0), MDefinition::NoTruncate);
block()->insertBefore(this, limit);
MToDouble *toDouble = MToDouble::New(alloc, limit);
block()->insertBefore(this, toDouble);
return toDouble;
}
// max(int32, cte <= INT32_MIN) = int32
if (val.isDouble() && val.toDouble() < INT32_MIN && isMax()) {
MLimitedTruncate *limit =
MLimitedTruncate::New(alloc, operand->getOperand(0), MDefinition::NoTruncate);
block()->insertBefore(this, limit);
MToDouble *toDouble = MToDouble::New(alloc, limit);
block()->insertBefore(this, toDouble);
return toDouble;
}
}
return this;
}
bool
MAbs::fallible() const
{
@ -2976,7 +3011,7 @@ MCompare::tryFold(bool *result)
}
bool
MCompare::evaluateConstantOperands(bool *result)
MCompare::evaluateConstantOperands(TempAllocator &alloc, bool *result)
{
if (type() != MIRType_Boolean && type() != MIRType_Int32)
return false;
@ -2984,6 +3019,73 @@ MCompare::evaluateConstantOperands(bool *result)
MDefinition *left = getOperand(0);
MDefinition *right = getOperand(1);
if (compareType() == Compare_Double) {
// Optimize "MCompare MConstant (MToDouble SomethingInInt32Range).
// In most cases the MToDouble was added, because the constant is
// a double.
// e.g. v < 9007199254740991, where v is an int32 is always true.
if (!lhs()->isConstant() && !rhs()->isConstant())
return false;
MDefinition *operand = left->isConstant() ? right : left;
MConstant *constant = left->isConstant() ? left->toConstant() : right->toConstant();
MOZ_ASSERT(constant->value().isDouble());
double cte = constant->value().toDouble();
if (operand->isToDouble() && operand->getOperand(0)->type() == MIRType_Int32) {
bool replaced = false;
switch (jsop_) {
case JSOP_LT:
if (cte > INT32_MAX || cte < INT32_MIN) {
*result = !((constant == lhs()) ^ (cte < INT32_MIN));
replaced = true;
}
break;
case JSOP_LE:
if (cte >= INT32_MAX || cte <= INT32_MIN) {
*result = !((constant == lhs()) ^ (cte <= INT32_MIN));
replaced = true;
}
break;
case JSOP_GT:
if (cte > INT32_MAX || cte < INT32_MIN) {
*result = !((constant == rhs()) ^ (cte < INT32_MIN));
replaced = true;
}
break;
case JSOP_GE:
if (cte >= INT32_MAX || cte <= INT32_MIN) {
*result = !((constant == rhs()) ^ (cte <= INT32_MIN));
replaced = true;
}
break;
case JSOP_STRICTEQ: // Fall through.
case JSOP_EQ:
if (cte > INT32_MAX || cte < INT32_MIN) {
*result = false;
replaced = true;
}
break;
case JSOP_STRICTNE: // Fall through.
case JSOP_NE:
if (cte > INT32_MAX || cte < INT32_MIN) {
*result = true;
replaced = true;
}
break;
default:
MOZ_CRASH("Unexpected op.");
}
if (replaced) {
MLimitedTruncate *limit =
MLimitedTruncate::New(alloc, operand->getOperand(0), MDefinition::NoTruncate);
limit->setGuardUnchecked();
block()->insertBefore(this, limit);
return true;
}
}
}
if (!left->isConstant() || !right->isConstant())
return false;
@ -3092,7 +3194,7 @@ MCompare::foldsTo(TempAllocator &alloc)
{
bool result;
if (tryFold(&result) || evaluateConstantOperands(&result)) {
if (tryFold(&result) || evaluateConstantOperands(alloc, &result)) {
if (type() == MIRType_Int32)
return MConstant::New(alloc, Int32Value(result));

3
js/src/jit/MIR.h
View File

@ -3643,7 +3643,7 @@ class MCompare
CompareType compareType);
bool tryFold(bool *result);
bool evaluateConstantOperands(bool *result);
bool evaluateConstantOperands(TempAllocator &alloc, bool *result);
MDefinition *foldsTo(TempAllocator &alloc);
void filtersUndefinedOrNull(bool trueBranch, MDefinition **subject, bool *filtersUndefined,
bool *filtersNull);
@ -5008,6 +5008,7 @@ class MMinMax
AliasSet getAliasSet() const {
return AliasSet::None();
}
MDefinition *foldsTo(TempAllocator &alloc);
void computeRange(TempAllocator &alloc);
bool writeRecoverData(CompactBufferWriter &writer) const;
bool canRecoverOnBailout() const {