Revision: 19896
Author: [email protected]
Date: Thu Mar 13 13:57:21 2014 UTC
Log: Correctly retain argument value when deopting from Math.round on
x64.
[email protected]
BUG=351624
LOG=N
Review URL: https://codereview.chromium.org/199013002
http://code.google.com/p/v8/source/detail?r=19896
Added:
/branches/bleeding_edge/test/mjsunit/regress/regress-351624.js
Modified:
/branches/bleeding_edge/src/x64/lithium-codegen-x64.cc
/branches/bleeding_edge/src/x64/lithium-x64.cc
/branches/bleeding_edge/src/x64/lithium-x64.h
=======================================
--- /dev/null
+++ /branches/bleeding_edge/test/mjsunit/regress/regress-351624.js Thu Mar
13 13:57:21 2014 UTC
@@ -0,0 +1,23 @@
+// Copyright 2014 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --allow-natives-syntax
+
+var big = 1e10;
+var backup = new Float64Array(1);
+
+function mult0(val){
+ var prod = val * big;
+ backup[0] = prod;
+ var rounded = Math.round(prod);
+ assertEquals(prod, backup[0]);
+ return rounded;
+}
+
+var count = 5;
+for (var i = 0; i < count; i++) {
+ if (i == count - 1) %OptimizeFunctionOnNextCall(mult0);
+ var result = mult0(-1);
+ assertEquals(result, -big);
+}
=======================================
--- /branches/bleeding_edge/src/x64/lithium-codegen-x64.cc Thu Mar 13
08:17:44 2014 UTC
+++ /branches/bleeding_edge/src/x64/lithium-codegen-x64.cc Thu Mar 13
13:57:21 2014 UTC
@@ -3604,10 +3604,11 @@
const XMMRegister xmm_scratch = double_scratch0();
Register output_reg = ToRegister(instr->result());
XMMRegister input_reg = ToDoubleRegister(instr->value());
+ XMMRegister input_temp = ToDoubleRegister(instr->temp());
static int64_t one_half = V8_INT64_C(0x3FE0000000000000); // 0.5
static int64_t minus_one_half = V8_INT64_C(0xBFE0000000000000); // -0.5
- Label done, round_to_zero, below_one_half, do_not_compensate, restore;
+ Label done, round_to_zero, below_one_half;
Label::Distance dist = DeoptEveryNTimes() ? Label::kFar : Label::kNear;
__ movq(kScratchRegister, one_half);
__ movq(xmm_scratch, kScratchRegister);
@@ -3631,21 +3632,19 @@
// CVTTSD2SI rounds towards zero, we use ceil(x - (-0.5)) and then
// compare and compensate.
- __ movq(kScratchRegister, input_reg); // Back up input_reg.
- __ subsd(input_reg, xmm_scratch);
- __ cvttsd2si(output_reg, input_reg);
+ __ movq(input_temp, input_reg); // Do not alter input_reg.
+ __ subsd(input_temp, xmm_scratch);
+ __ cvttsd2si(output_reg, input_temp);
// Catch minint due to overflow, and to prevent overflow when
compensating.
__ cmpl(output_reg, Immediate(0x80000000));
__ RecordComment("D2I conversion overflow");
DeoptimizeIf(equal, instr->environment());
__ Cvtlsi2sd(xmm_scratch, output_reg);
- __ ucomisd(input_reg, xmm_scratch);
- __ j(equal, &restore, Label::kNear);
+ __ ucomisd(xmm_scratch, input_temp);
+ __ j(equal, &done, dist);
__ subl(output_reg, Immediate(1));
// No overflow because we already ruled out minint.
- __ bind(&restore);
- __ movq(input_reg, kScratchRegister); // Restore input_reg.
__ jmp(&done, dist);
__ bind(&round_to_zero);
=======================================
--- /branches/bleeding_edge/src/x64/lithium-x64.cc Thu Mar 13 07:58:58 2014
UTC
+++ /branches/bleeding_edge/src/x64/lithium-x64.cc Thu Mar 13 13:57:21 2014
UTC
@@ -1133,8 +1133,9 @@
LInstruction* LChunkBuilder::DoMathRound(HUnaryMathOperation* instr) {
- LOperand* input = UseRegisterAtStart(instr->value());
- LMathRound* result = new(zone()) LMathRound(input);
+ LOperand* input = UseRegister(instr->value());
+ LOperand* temp = FixedTemp(xmm4);
+ LMathRound* result = new(zone()) LMathRound(input, temp);
return AssignEnvironment(DefineAsRegister(result));
}
=======================================
--- /branches/bleeding_edge/src/x64/lithium-x64.h Thu Mar 13 06:11:52 2014
UTC
+++ /branches/bleeding_edge/src/x64/lithium-x64.h Thu Mar 13 13:57:21 2014
UTC
@@ -835,13 +835,15 @@
};
-class LMathRound V8_FINAL : public LTemplateInstruction<1, 1, 0> {
+class LMathRound V8_FINAL : public LTemplateInstruction<1, 1, 1> {
public:
- explicit LMathRound(LOperand* value) {
+ explicit LMathRound(LOperand* value, LOperand* temp) {
inputs_[0] = value;
+ temps_[0] = temp;
}
LOperand* value() { return inputs_[0]; }
+ LOperand* temp() { return temps_[0]; }
DECLARE_CONCRETE_INSTRUCTION(MathRound, "math-round")
DECLARE_HYDROGEN_ACCESSOR(UnaryMathOperation)
--
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