Reviewers: Kevin Millikin,
Description:
Merge r6573 to 3.0 branch. This is a fix for issue 1088, Math.pow(-0, 0.5).
Please review this at http://codereview.chromium.org/6334056/
SVN Base: http://v8.googlecode.com/svn/branches/3.0/
Affected files:
M src/arm/codegen-arm.cc
M src/assembler.cc
M src/ia32/code-stubs-ia32.cc
M src/ia32/codegen-ia32.cc
M src/ia32/lithium-codegen-ia32.cc
M src/x64/codegen-x64.cc
M test/mjsunit/math-pow.js
Index: src/arm/codegen-arm.cc
===================================================================
--- src/arm/codegen-arm.cc (revision 6585)
+++ src/arm/codegen-arm.cc (working copy)
@@ -4698,12 +4698,15 @@
runtime.entry_label(),
AVOID_NANS_AND_INFINITIES);
+ // Convert -0 into +0 by adding +0.
+ __ vmov(d2, 0.0);
+ __ vadd(d0, d2, d0);
// Load 1.0 into d2.
__ vmov(d2, 1.0);
- // Calculate the reciprocal of the square root. 1/sqrt(x) = sqrt(1/x).
+ // Calculate the reciprocal of the square root.
+ __ vsqrt(d0, d0);
__ vdiv(d0, d2, d0);
- __ vsqrt(d0, d0);
__ b(&allocate_return);
@@ -4717,6 +4720,9 @@
scratch1, scratch2, heap_number_map, s0,
runtime.entry_label(),
AVOID_NANS_AND_INFINITIES);
+ // Convert -0 into +0 by adding +0.
+ __ vmov(d2, 0.0);
+ __ vadd(d0, d2, d0);
__ vsqrt(d0, d0);
__ bind(&allocate_return);
Index: src/assembler.cc
===================================================================
--- src/assembler.cc (revision 6585)
+++ src/assembler.cc (working copy)
@@ -838,8 +838,8 @@
return power_double_int(x, y_int); // Returns 1.0 for exponent 0.
}
if (!isinf(x)) {
- if (y == 0.5) return sqrt(x);
- if (y == -0.5) return 1.0 / sqrt(x);
+ if (y == 0.5) return sqrt(x + 0.0); // -0 must be converted to +0.
+ if (y == -0.5) return 1.0 / sqrt(x + 0.0);
}
if (isnan(y) || ((x == 1 || x == -1) && isinf(y))) {
return OS::nan_value();
Index: src/ia32/code-stubs-ia32.cc
===================================================================
--- src/ia32/code-stubs-ia32.cc (revision 6585)
+++ src/ia32/code-stubs-ia32.cc (working copy)
@@ -3477,10 +3477,12 @@
__ j(not_equal, ¬_minus_half);
// Calculates reciprocal of square root.
- // Note that 1/sqrt(x) = sqrt(1/x))
- __ divsd(xmm3, xmm0);
+ // sqrtsd returns -0 when input is -0. ECMA spec requires +0.
+ __ xorpd(xmm1, xmm1);
+ __ addsd(xmm1, xmm0);
+ __ sqrtsd(xmm1, xmm1);
+ __ divsd(xmm3, xmm1);
__ movsd(xmm1, xmm3);
- __ sqrtsd(xmm1, xmm1);
__ jmp(&allocate_return);
// Test for 0.5.
@@ -3492,7 +3494,9 @@
__ ucomisd(xmm2, xmm1);
__ j(not_equal, &call_runtime);
// Calculates square root.
- __ movsd(xmm1, xmm0);
+ // sqrtsd returns -0 when input is -0. ECMA spec requires +0.
+ __ xorpd(xmm1, xmm1);
+ __ addsd(xmm1, xmm0);
__ sqrtsd(xmm1, xmm1);
__ bind(&allocate_return);
Index: src/ia32/codegen-ia32.cc
===================================================================
--- src/ia32/codegen-ia32.cc (revision 6585)
+++ src/ia32/codegen-ia32.cc (working copy)
@@ -7951,10 +7951,12 @@
__ j(not_equal, ¬_minus_half);
// Calculates reciprocal of square root.
- // Note that 1/sqrt(x) = sqrt(1/x))
- __ divsd(xmm3, xmm0);
+ // sqrtsd returns -0 when input is -0. ECMA spec requires +0.
+ __ xorpd(xmm1, xmm1);
+ __ addsd(xmm1, xmm0);
+ __ sqrtsd(xmm1, xmm1);
+ __ divsd(xmm3, xmm1);
__ movsd(xmm1, xmm3);
- __ sqrtsd(xmm1, xmm1);
__ jmp(&allocate_return);
// Test for 0.5.
@@ -7966,7 +7968,9 @@
__ ucomisd(xmm2, xmm1);
call_runtime.Branch(not_equal);
// Calculates square root.
- __ movsd(xmm1, xmm0);
+ // sqrtsd returns -0 when input is -0. ECMA spec requires +0.
+ __ xorpd(xmm1, xmm1);
+ __ addsd(xmm1, xmm0);
__ sqrtsd(xmm1, xmm1);
JumpTarget done;
Index: src/ia32/lithium-codegen-ia32.cc
===================================================================
--- src/ia32/lithium-codegen-ia32.cc (revision 6585)
+++ src/ia32/lithium-codegen-ia32.cc (working copy)
@@ -2388,6 +2388,8 @@
__ movdbl(xmm_scratch, Operand::StaticVariable(negative_infinity));
__ ucomisd(xmm_scratch, input_reg);
DeoptimizeIf(equal, instr->environment());
+ __ xorpd(xmm_scratch, xmm_scratch);
+ __ addsd(input_reg, xmm_scratch); // Convert -0 to +0.
__ sqrtsd(input_reg, input_reg);
}
Index: src/x64/codegen-x64.cc
===================================================================
--- src/x64/codegen-x64.cc (revision 6585)
+++ src/x64/codegen-x64.cc (working copy)
@@ -6969,10 +6969,12 @@
__ j(not_equal, ¬_minus_half);
// Calculates reciprocal of square root.
- // Note that 1/sqrt(x) = sqrt(1/x))
- __ divsd(xmm3, xmm0);
+ // sqrtsd returns -0 when input is -0. ECMA spec requires +0.
+ __ xorpd(xmm1, xmm1);
+ __ addsd(xmm1, xmm0);
+ __ sqrtsd(xmm1, xmm1);
+ __ divsd(xmm3, xmm1);
__ movsd(xmm1, xmm3);
- __ sqrtsd(xmm1, xmm1);
__ jmp(&allocate_return);
// Test for 0.5.
@@ -6985,7 +6987,9 @@
call_runtime.Branch(not_equal);
// Calculates square root.
- __ movsd(xmm1, xmm0);
+ // sqrtsd returns -0 when input is -0. ECMA spec requires +0.
+ __ xorpd(xmm1, xmm1);
+ __ addsd(xmm1, xmm0);
__ sqrtsd(xmm1, xmm1);
JumpTarget done;
Index: test/mjsunit/math-pow.js
===================================================================
--- test/mjsunit/math-pow.js (revision 6585)
+++ test/mjsunit/math-pow.js (working copy)
@@ -58,10 +58,11 @@
assertEquals(Infinity, Math.pow(2, Infinity));
assertEquals(Infinity, Math.pow(-2, Infinity));
-assertEquals(+0, Math.pow(1.1, -Infinity));
-assertEquals(+0, Math.pow(-1.1, -Infinity));
-assertEquals(+0, Math.pow(2, -Infinity));
-assertEquals(+0, Math.pow(-2, -Infinity));
+// Because +0 == -0, we need to compare 1/{+,-}0 to {+,-}Infinity
+assertEquals(+Infinity, 1/Math.pow(1.1, -Infinity));
+assertEquals(+Infinity, 1/Math.pow(-1.1, -Infinity));
+assertEquals(+Infinity, 1/Math.pow(2, -Infinity));
+assertEquals(+Infinity, 1/Math.pow(-2, -Infinity));
assertEquals(NaN, Math.pow(1, Infinity));
assertEquals(NaN, Math.pow(1, -Infinity));
@@ -81,8 +82,8 @@
assertEquals(Infinity, Math.pow(Infinity, 0.1));
assertEquals(Infinity, Math.pow(Infinity, 2));
-assertEquals(+0, Math.pow(Infinity, -0.1));
-assertEquals(+0, Math.pow(Infinity, -2));
+assertEquals(+Infinity, 1/Math.pow(Infinity, -0.1));
+assertEquals(+Infinity, 1/Math.pow(Infinity, -2));
assertEquals(-Infinity, Math.pow(-Infinity, 3));
assertEquals(-Infinity, Math.pow(-Infinity, 13));
@@ -90,23 +91,23 @@
assertEquals(Infinity, Math.pow(-Infinity, 3.1));
assertEquals(Infinity, Math.pow(-Infinity, 2));
-assertEquals(-0, Math.pow(-Infinity, -3));
-assertEquals(-0, Math.pow(-Infinity, -13));
+assertEquals(-Infinity, 1/Math.pow(-Infinity, -3));
+assertEquals(-Infinity, 1/Math.pow(-Infinity, -13));
-assertEquals(+0, Math.pow(-Infinity, -3.1));
-assertEquals(+0, Math.pow(-Infinity, -2));
+assertEquals(+Infinity, 1/Math.pow(-Infinity, -3.1));
+assertEquals(+Infinity, 1/Math.pow(-Infinity, -2));
-assertEquals(+0, Math.pow(+0, 1.1));
-assertEquals(+0, Math.pow(+0, 2));
+assertEquals(+Infinity, 1/Math.pow(+0, 1.1));
+assertEquals(+Infinity, 1/Math.pow(+0, 2));
assertEquals(Infinity, Math.pow(+0, -1.1));
assertEquals(Infinity, Math.pow(+0, -2));
-assertEquals(-0, Math.pow(-0, 3));
-assertEquals(-0, Math.pow(-0, 13));
+assertEquals(-Infinity, 1/Math.pow(-0, 3));
+assertEquals(-Infinity, 1/Math.pow(-0, 13));
-assertEquals(+0, Math.pow(-0, 3.1));
-assertEquals(+0, Math.pow(-0, 2));
+assertEquals(+Infinity, 1/Math.pow(-0, 3.1));
+assertEquals(+Infinity, 1/Math.pow(-0, 2));
assertEquals(-Infinity, Math.pow(-0, -3));
assertEquals(-Infinity, Math.pow(-0, -13));
@@ -123,6 +124,18 @@
assertEquals(NaN, Math.pow(-1000, 1.1));
assertEquals(NaN, Math.pow(-1000, -1.1));
+assertEquals(+Infinity, 1/Math.pow(-0, 0.5));
+assertEquals(+Infinity, 1/Math.pow(-0, 0.6));
+assertEquals(-Infinity, 1/Math.pow(-0, 1));
+assertEquals(-Infinity, 1/Math.pow(-0, 10000000001));
+
+assertEquals(+Infinity, Math.pow(-0, -0.5));
+assertEquals(+Infinity, Math.pow(-0, -0.6));
+assertEquals(-Infinity, Math.pow(-0, -1));
+assertEquals(-Infinity, Math.pow(-0, -10000000001));
+
+
+
// Tests from Sputnik S8.5_A13_T1.
assertTrue((1*((Math.pow(2,53))-1)*(Math.pow(2,-1074))) ===
4.4501477170144023e-308);
assertTrue((1*(Math.pow(2,52))*(Math.pow(2,-1074))) ===
2.2250738585072014e-308);
--
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