Reviewers: danno, Benedikt Meurer, Paul Lind, kisg, palfia, dusmil,
Description:
MIPS: Cleanup some of the range uses in ModI/DivI.
Port r19796 (2b8ff32)
BUG=v8:3204
LOG=y
Please review this at https://codereview.chromium.org/194863004/
SVN Base: https://github.com/v8/v8.git@gbl
Affected files (+36, -38 lines):
M src/mips/lithium-codegen-mips.cc
M src/mips/lithium-mips.cc
Index: src/mips/lithium-codegen-mips.cc
diff --git a/src/mips/lithium-codegen-mips.cc
b/src/mips/lithium-codegen-mips.cc
index
9bebb7bb3a247ca6e87a1c5e2d848c1fd4d8814a..435321a3bd8ff175e103164c4fcc7720b4e9f654
100644
--- a/src/mips/lithium-codegen-mips.cc
+++ b/src/mips/lithium-codegen-mips.cc
@@ -1095,8 +1095,6 @@ void LCodeGen::DoModByPowerOf2I(LModByPowerOf2I*
instr) {
void LCodeGen::DoModI(LModI* instr) {
HMod* hmod = instr->hydrogen();
- HValue* left = hmod->left();
- HValue* right = hmod->right();
const Register left_reg = ToRegister(instr->left());
const Register right_reg = ToRegister(instr->right());
const Register result_reg = ToRegister(instr->result());
@@ -1107,24 +1105,28 @@ void LCodeGen::DoModI(LModI* instr) {
Label done;
// Check for x % 0, we have to deopt in this case because we can't
return a
// NaN.
- if (right->CanBeZero()) {
+ if (hmod->CheckFlag(HValue::kCanBeDivByZero)) {
DeoptimizeIf(eq, instr->environment(), right_reg, Operand(zero_reg));
}
- // Check for kMinInt % -1, we have to deopt if we care about -0, because
we
- // can't return that.
- if (left->RangeCanInclude(kMinInt) && right->RangeCanInclude(-1)) {
- Label left_not_min_int;
- __ Branch(&left_not_min_int, ne, left_reg, Operand(kMinInt));
- // TODO(svenpanne) Don't deopt when we don't care about -0.
- DeoptimizeIf(eq, instr->environment(), right_reg, Operand(-1));
- __ bind(&left_not_min_int);
+ // Check for kMinInt % -1, div will return kMinInt, which is not what we
+ // want. We have to deopt if we care about -0, because we can't return
that.
+ if (hmod->CheckFlag(HValue::kCanOverflow)) {
+ Label no_overflow_possible;
+ __ Branch(&no_overflow_possible, ne, left_reg, Operand(kMinInt));
+ if (hmod->CheckFlag(HValue::kBailoutOnMinusZero)) {
+ DeoptimizeIf(eq, instr->environment(), right_reg, Operand(-1));
+ } else {
+ __ Branch(&no_overflow_possible, ne, right_reg, Operand(-1));
+ __ Branch(USE_DELAY_SLOT, &done);
+ __ mov(result_reg, zero_reg);
+ }
+ __ bind(&no_overflow_possible);
}
- // TODO(svenpanne) Only emit the test/deopt if we have to.
+ // If we care about -0, test if the dividend is <0 and the result is 0.
__ Branch(USE_DELAY_SLOT, &done, ge, left_reg, Operand(zero_reg));
__ mfhi(result_reg);
-
if (hmod->CheckFlag(HValue::kBailoutOnMinusZero)) {
DeoptimizeIf(eq, instr->environment(), result_reg, Operand(zero_reg));
}
@@ -1133,6 +1135,7 @@ void LCodeGen::DoModI(LModI* instr) {
void LCodeGen::DoDivI(LDivI* instr) {
+ HBinaryOperation* hdiv = instr->hydrogen();
const Register left = ToRegister(instr->left());
const Register right = ToRegister(instr->right());
const Register result = ToRegister(instr->result());
@@ -1142,12 +1145,12 @@ void LCodeGen::DoDivI(LDivI* instr) {
__ div(left, right);
// Check for x / 0.
- if (instr->hydrogen()->CheckFlag(HValue::kCanBeDivByZero)) {
+ if (hdiv->CheckFlag(HValue::kCanBeDivByZero)) {
DeoptimizeIf(eq, instr->environment(), right, Operand(zero_reg));
}
// Check for (0 / -x) that will produce negative zero.
- if (instr->hydrogen()->CheckFlag(HValue::kBailoutOnMinusZero)) {
+ if (hdiv->CheckFlag(HValue::kBailoutOnMinusZero)) {
Label left_not_zero;
__ Branch(&left_not_zero, ne, left, Operand(zero_reg));
DeoptimizeIf(lt, instr->environment(), right, Operand(zero_reg));
@@ -1155,14 +1158,15 @@ void LCodeGen::DoDivI(LDivI* instr) {
}
// Check for (kMinInt / -1).
- if (instr->hydrogen()->CheckFlag(HValue::kCanOverflow)) {
+ if (hdiv->CheckFlag(HValue::kCanOverflow) &&
+ !hdiv->CheckFlag(HValue::kAllUsesTruncatingToInt32)) {
Label left_not_min_int;
__ Branch(&left_not_min_int, ne, left, Operand(kMinInt));
DeoptimizeIf(eq, instr->environment(), right, Operand(-1));
__ bind(&left_not_min_int);
}
- if
(!instr->hydrogen()->CheckFlag(HInstruction::kAllUsesTruncatingToInt32)) {
+ if (!hdiv->CheckFlag(HValue::kAllUsesTruncatingToInt32)) {
__ mfhi(result);
DeoptimizeIf(ne, instr->environment(), result, Operand(zero_reg));
}
@@ -1233,8 +1237,7 @@ void
LCodeGen::DoFlooringDivByConstI(LFlooringDivByConstI* instr) {
// Check for (0 / -x) that will produce negative zero.
HMathFloorOfDiv* hdiv = instr->hydrogen();
- if (hdiv->CheckFlag(HValue::kBailoutOnMinusZero) &&
- hdiv->left()->RangeCanInclude(0) && divisor < 0) {
+ if (hdiv->CheckFlag(HValue::kBailoutOnMinusZero) && divisor < 0) {
DeoptimizeIf(eq, instr->environment(), dividend, Operand(zero_reg));
}
Index: src/mips/lithium-mips.cc
diff --git a/src/mips/lithium-mips.cc b/src/mips/lithium-mips.cc
index
d2cc39be9a206d70c47f5768ec51ad2caa932b1e..fd0a2aa25839158b6d799e4638acea0ff99c1b34
100644
--- a/src/mips/lithium-mips.cc
+++ b/src/mips/lithium-mips.cc
@@ -1289,8 +1289,7 @@ LInstruction*
LChunkBuilder::DoFlooringDivByConstI(HMathFloorOfDiv* instr) {
DefineAsRegister(new(zone()) LFlooringDivByConstI(dividend,
divisor));
bool can_deopt =
divisor == 0 ||
- (instr->CheckFlag(HValue::kBailoutOnMinusZero) &&
- instr->left()->RangeCanInclude(0) && divisor < 0);
+ (instr->CheckFlag(HValue::kBailoutOnMinusZero) && divisor < 0);
return can_deopt ? AssignEnvironment(result) : result;
}
@@ -1317,12 +1316,12 @@ LInstruction* LChunkBuilder::DoModByPowerOf2I(HMod*
instr) {
ASSERT(instr->right()->representation().Equals(instr->representation()));
LOperand* dividend = UseRegisterAtStart(instr->left());
int32_t divisor = instr->right()->GetInteger32Constant();
- LInstruction* result =
- DefineSameAsFirst(new(zone()) LModByPowerOf2I(dividend, divisor));
- bool can_deopt =
- instr->CheckFlag(HValue::kBailoutOnMinusZero) &&
- instr->left()->CanBeNegative();
- return can_deopt ? AssignEnvironment(result) : result;
+ LInstruction* result = DefineSameAsFirst(new(zone()) LModByPowerOf2I(
+ dividend, divisor));
+ if (instr->CheckFlag(HValue::kBailoutOnMinusZero)) {
+ result = AssignEnvironment(result);
+ }
+ return result;
}
@@ -1332,17 +1331,13 @@ LInstruction* LChunkBuilder::DoModI(HMod* instr) {
ASSERT(instr->right()->representation().Equals(instr->representation()));
LOperand* dividend = UseRegister(instr->left());
LOperand* divisor = UseRegister(instr->right());
- LModI* mod = new(zone()) LModI(dividend,
- divisor);
- LInstruction* result = DefineAsRegister(mod);
- bool can_deopt = (instr->right()->CanBeZero() ||
- (instr->left()->RangeCanInclude(kMinInt) &&
- instr->right()->RangeCanInclude(-1) &&
- instr->CheckFlag(HValue::kBailoutOnMinusZero)) ||
- (instr->left()->CanBeNegative() &&
- instr->CanBeZero() &&
- instr->CheckFlag(HValue::kBailoutOnMinusZero)));
- return can_deopt ? AssignEnvironment(result) : result;
+ LInstruction* result = DefineAsRegister(new(zone()) LModI(
+ dividend, divisor));
+ if (instr->CheckFlag(HValue::kCanBeDivByZero) ||
+ instr->CheckFlag(HValue::kBailoutOnMinusZero)) {
+ result = AssignEnvironment(result);
+ }
+ return result;
}
--
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