Reviewers: Jakob,
Description:
Fix a bug in Div when all uses are truncating
Refine the related test cases to cover truncating cases
BUG=
Please review this at https://codereview.chromium.org/22964004/
SVN Base: https://github.com/v8/v8.git@master
Affected files:
M src/arm/lithium-codegen-arm.cc
M src/ia32/lithium-codegen-ia32.cc
M src/x64/lithium-codegen-x64.cc
M test/mjsunit/shift-for-integer-div.js
Index: src/arm/lithium-codegen-arm.cc
diff --git a/src/arm/lithium-codegen-arm.cc b/src/arm/lithium-codegen-arm.cc
index
9ec80f819a062dbf3078fc4a0487b765177a19cb..d090f9203f66046ff8f4eecba405867802e3da87
100644
--- a/src/arm/lithium-codegen-arm.cc
+++ b/src/arm/lithium-codegen-arm.cc
@@ -1394,10 +1394,18 @@ void LCodeGen::DoDivI(LDivI* instr) {
if (test_value != 0) {
if (instr->hydrogen()->CheckFlag(
HInstruction::kAllUsesTruncatingToInt32)) {
+ Label negative, done;
__ cmp(dividend, Operand(0));
+ __ b(lt, &negative);
+ __ mov(dividend, Operand(dividend, ASR, power));
+ if (divisor < 0) __ rsb(dividend, dividend, Operand(0));
+ __ jmp(&done);
+
+ __ bind(&negative);
__ rsb(dividend, dividend, Operand(0), LeaveCC, lt);
__ mov(dividend, Operand(dividend, ASR, power));
- if (divisor > 0) __ rsb(dividend, dividend, Operand(0), LeaveCC,
lt);
+ if (divisor > 0) __ rsb(dividend, dividend, Operand(0));
+ __ bind(&done);
return; // Don't fall through to "__ rsb" below.
} else {
// Deoptimize if remainder is not 0.
Index: src/ia32/lithium-codegen-ia32.cc
diff --git a/src/ia32/lithium-codegen-ia32.cc
b/src/ia32/lithium-codegen-ia32.cc
index
19c553bfa517a7b47bf462e7e8affae561830095..a6c1f5a7ed4975481f7709a96246aaa0ade2b8e4
100644
--- a/src/ia32/lithium-codegen-ia32.cc
+++ b/src/ia32/lithium-codegen-ia32.cc
@@ -1441,6 +1441,7 @@ void LCodeGen::DoDivI(LDivI* instr) {
__ cmp(dividend, 0);
__ j(less, &negative, Label::kNear);
__ sar(dividend, power);
+ if (divisor < 0) __ neg(dividend);
__ jmp(&done, Label::kNear);
__ bind(&negative);
Index: src/x64/lithium-codegen-x64.cc
diff --git a/src/x64/lithium-codegen-x64.cc b/src/x64/lithium-codegen-x64.cc
index
abb8c77b5b772cd0440251034944771b8277abd9..16478b287f6dfb99bfcf966c3f94243456c28d2c
100644
--- a/src/x64/lithium-codegen-x64.cc
+++ b/src/x64/lithium-codegen-x64.cc
@@ -1216,6 +1216,7 @@ void LCodeGen::DoDivI(LDivI* instr) {
__ cmpl(dividend, Immediate(0));
__ j(less, &negative, Label::kNear);
__ sarl(dividend, Immediate(power));
+ if (divisor < 0) __ negl(dividend);
__ jmp(&done, Label::kNear);
__ bind(&negative);
Index: test/mjsunit/shift-for-integer-div.js
diff --git a/test/mjsunit/shift-for-integer-div.js
b/test/mjsunit/shift-for-integer-div.js
index
0fe1262292137e4146d5054bde05537a75e32032..ac8d90682d930541f061b81be66710d9b6803f07
100644
--- a/test/mjsunit/shift-for-integer-div.js
+++ b/test/mjsunit/shift-for-integer-div.js
@@ -1,4 +1,4 @@
-// Copyright 2012 the V8 project authors. All rights reserved.
+// Copyright 2013 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
@@ -25,35 +25,63 @@
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+// Flags: --allow-natives-syntax
+
function divp4(x) {
return x / 4;
}
-for (var i = 0; i < 10000; i+=4) {
- assertEquals(i >> 2, divp4(i));
-}
-
+divp4(8);
+divp4(8);
+%OptimizeFunctionOnNextCall(divp4);
+assertEquals(2, divp4(8));
assertEquals(0.5, divp4(2));
+
function divn4(x) {
return x / (-4);
}
-for (var i = 0; i < 10000; i+=4) {
- assertEquals(-(i >> 2), divn4(i));
-}
-
+divn4(8);
+divn4(8);
+%OptimizeFunctionOnNextCall(divn4);
+assertEquals(-2, divn4(8));
+// Check for (0 / -x)
assertEquals(-0, divn4(0));
+// Check for (kMinInt / -1)
function divn1(x) {
return x / (-1);
}
-for (var i = 0; i < 10000; i++) {
- assertEquals(-i, divn1(i));
+var two_31 = 1 << 31;
+divn1(2);
+divn1(2);
+%OptimizeFunctionOnNextCall(divn1);
+assertEquals(-2, divn1(2));
+assertEquals(two_31, divn1(-two_31));
+
+
+//Check for truncating to int32 case
+function divp4t(x) {
+ return (x / 4) | 0;
}
-var min_int = -(0x7FFFFFFF)-1;
-assertEquals(-min_int, divn1(min_int));
+divp4t(8);
+divp4t(8);
+%OptimizeFunctionOnNextCall(divp4t);
+assertEquals(-1, divp4t(-5));
+assertEquals(1, divp4t(5));
+assertOptimized(divp4t);
+
+function divn4t(x) {
+ return (x / -4) | 0;
+}
+divn4t(8);
+divn4t(8);
+%OptimizeFunctionOnNextCall(divn4t);
+assertEquals(1, divn4t(-5));
+assertEquals(-1, divn4t(5));
+assertOptimized(divn4t);
--
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