Revision: 16997
Author: [email protected]
Date: Fri Sep 27 16:16:40 2013 UTC
Log: MIPS: Improve integer multiplication.
Port r16576 (8ce78a4)
TEST=test/mjsunit/lithium/MulI.js
BUG=
[email protected]
Review URL: https://codereview.chromium.org/25050002
Patch from Balazs Kilvady <[email protected]>.
http://code.google.com/p/v8/source/detail?r=16997
Modified:
/branches/bleeding_edge/src/mips/lithium-codegen-mips.cc
/branches/bleeding_edge/src/mips/lithium-mips.cc
/branches/bleeding_edge/src/mips/lithium-mips.h
=======================================
--- /branches/bleeding_edge/src/mips/lithium-codegen-mips.cc Wed Sep 25
00:41:37 2013 UTC
+++ /branches/bleeding_edge/src/mips/lithium-codegen-mips.cc Fri Sep 27
16:16:40 2013 UTC
@@ -1403,11 +1403,11 @@
Register left = ToRegister(instr->left());
LOperand* right_op = instr->right();
- bool can_overflow = instr->hydrogen()->CheckFlag(HValue::kCanOverflow);
bool bailout_on_minus_zero =
instr->hydrogen()->CheckFlag(HValue::kBailoutOnMinusZero);
+ bool overflow = instr->hydrogen()->CheckFlag(HValue::kCanOverflow);
- if (right_op->IsConstantOperand() && !can_overflow) {
+ if (right_op->IsConstantOperand()) {
int32_t constant = ToInteger32(LConstantOperand::cast(right_op));
if (bailout_on_minus_zero && (constant < 0)) {
@@ -1418,7 +1418,12 @@
switch (constant) {
case -1:
- __ Subu(result, zero_reg, left);
+ if (overflow) {
+ __ SubuAndCheckForOverflow(result, zero_reg, left, scratch);
+ DeoptimizeIf(lt, instr->environment(), scratch,
Operand(zero_reg));
+ } else {
+ __ Subu(result, zero_reg, left);
+ }
break;
case 0:
if (bailout_on_minus_zero) {
@@ -1439,27 +1444,23 @@
int32_t mask = constant >> 31;
uint32_t constant_abs = (constant + mask) ^ mask;
- if (IsPowerOf2(constant_abs) ||
- IsPowerOf2(constant_abs - 1) ||
- IsPowerOf2(constant_abs + 1)) {
- if (IsPowerOf2(constant_abs)) {
- int32_t shift = WhichPowerOf2(constant_abs);
- __ sll(result, left, shift);
- } else if (IsPowerOf2(constant_abs - 1)) {
- int32_t shift = WhichPowerOf2(constant_abs - 1);
- __ sll(scratch, left, shift);
- __ Addu(result, scratch, left);
- } else if (IsPowerOf2(constant_abs + 1)) {
- int32_t shift = WhichPowerOf2(constant_abs + 1);
- __ sll(scratch, left, shift);
- __ Subu(result, scratch, left);
- }
-
- // Correct the sign of the result is the constant is negative.
- if (constant < 0) {
- __ Subu(result, zero_reg, result);
- }
-
+ if (IsPowerOf2(constant_abs)) {
+ int32_t shift = WhichPowerOf2(constant_abs);
+ __ sll(result, left, shift);
+ // Correct the sign of the result if the constant is negative.
+ if (constant < 0) __ Subu(result, zero_reg, result);
+ } else if (IsPowerOf2(constant_abs - 1)) {
+ int32_t shift = WhichPowerOf2(constant_abs - 1);
+ __ sll(scratch, left, shift);
+ __ Addu(result, scratch, left);
+ // Correct the sign of the result if the constant is negative.
+ if (constant < 0) __ Subu(result, zero_reg, result);
+ } else if (IsPowerOf2(constant_abs + 1)) {
+ int32_t shift = WhichPowerOf2(constant_abs + 1);
+ __ sll(scratch, left, shift);
+ __ Subu(result, scratch, left);
+ // Correct the sign of the result if the constant is negative.
+ if (constant < 0) __ Subu(result, zero_reg, result);
} else {
// Generate standard code.
__ li(at, constant);
@@ -1468,12 +1469,10 @@
}
} else {
- Register right = EmitLoadRegister(right_op, scratch);
- if (bailout_on_minus_zero) {
- __ Or(ToRegister(instr->temp()), left, right);
- }
+ ASSERT(right_op->IsRegister());
+ Register right = ToRegister(right_op);
- if (can_overflow) {
+ if (overflow) {
// hi:lo = left * right.
if (instr->hydrogen()->representation().IsSmi()) {
__ SmiUntag(result, left);
@@ -1497,12 +1496,13 @@
}
if (bailout_on_minus_zero) {
- // Bail out if the result is supposed to be negative zero.
Label done;
- __ Branch(&done, ne, result, Operand(zero_reg));
- DeoptimizeIf(lt,
+ __ Xor(at, left, right);
+ __ Branch(&done, ge, at, Operand(zero_reg));
+ // Bail out if the result is minus zero.
+ DeoptimizeIf(eq,
instr->environment(),
- ToRegister(instr->temp()),
+ result,
Operand(zero_reg));
__ bind(&done);
}
=======================================
--- /branches/bleeding_edge/src/mips/lithium-mips.cc Fri Sep 27 13:48:19
2013 UTC
+++ /branches/bleeding_edge/src/mips/lithium-mips.cc Fri Sep 27 16:16:40
2013 UTC
@@ -1469,20 +1469,39 @@
if (instr->representation().IsSmiOrInteger32()) {
ASSERT(instr->left()->representation().Equals(instr->representation()));
ASSERT(instr->right()->representation().Equals(instr->representation()));
- LOperand* left;
- LOperand* right = UseOrConstant(instr->BetterRightOperand());
- LOperand* temp = NULL;
- if (instr->CheckFlag(HValue::kBailoutOnMinusZero) &&
- (instr->CheckFlag(HValue::kCanOverflow) ||
- !right->IsConstantOperand())) {
- left = UseRegister(instr->BetterLeftOperand());
- temp = TempRegister();
+ HValue* left = instr->BetterLeftOperand();
+ HValue* right = instr->BetterRightOperand();
+ LOperand* left_op;
+ LOperand* right_op;
+ bool can_overflow = instr->CheckFlag(HValue::kCanOverflow);
+ bool bailout_on_minus_zero =
instr->CheckFlag(HValue::kBailoutOnMinusZero);
+
+ if (right->IsConstant()) {
+ HConstant* constant = HConstant::cast(right);
+ int32_t constant_value = constant->Integer32Value();
+ // Constants -1, 0 and 1 can be optimized if the result can overflow.
+ // For other constants, it can be optimized only without overflow.
+ if (!can_overflow || ((constant_value >= -1) && (constant_value <=
1))) {
+ left_op = UseRegisterAtStart(left);
+ right_op = UseConstant(right);
+ } else {
+ if (bailout_on_minus_zero) {
+ left_op = UseRegister(left);
+ } else {
+ left_op = UseRegisterAtStart(left);
+ }
+ right_op = UseRegister(right);
+ }
} else {
- left = UseRegisterAtStart(instr->BetterLeftOperand());
+ if (bailout_on_minus_zero) {
+ left_op = UseRegister(left);
+ } else {
+ left_op = UseRegisterAtStart(left);
+ }
+ right_op = UseRegister(right);
}
- LMulI* mul = new(zone()) LMulI(left, right, temp);
- if (instr->CheckFlag(HValue::kCanOverflow) ||
- instr->CheckFlag(HValue::kBailoutOnMinusZero)) {
+ LMulI* mul = new(zone()) LMulI(left_op, right_op);
+ if (can_overflow || bailout_on_minus_zero) {
AssignEnvironment(mul);
}
return DefineAsRegister(mul);
=======================================
--- /branches/bleeding_edge/src/mips/lithium-mips.h Wed Sep 25 00:30:52
2013 UTC
+++ /branches/bleeding_edge/src/mips/lithium-mips.h Fri Sep 27 16:16:40
2013 UTC
@@ -688,17 +688,15 @@
};
-class LMulI V8_FINAL : public LTemplateInstruction<1, 2, 1> {
+class LMulI V8_FINAL : public LTemplateInstruction<1, 2, 0> {
public:
- LMulI(LOperand* left, LOperand* right, LOperand* temp) {
+ LMulI(LOperand* left, LOperand* right) {
inputs_[0] = left;
inputs_[1] = right;
- temps_[0] = temp;
}
LOperand* left() { return inputs_[0]; }
LOperand* right() { return inputs_[1]; }
- LOperand* temp() { return temps_[0]; }
DECLARE_CONCRETE_INSTRUCTION(MulI, "mul-i")
DECLARE_HYDROGEN_ACCESSOR(Mul)
--
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