Quickfix for DoMathPowHalf.

TEST=regress-397.js

Review URL: http://codereview.chromium.org/8769037

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@10140 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/ia32/assembler-ia32.cc

@@ -2057,6 +2057,16 @@ void Assembler::ucomisd(XMMRegister dst, XMMRegister src) {
 }
 
 
+void Assembler::ucomisd(XMMRegister dst, const Operand& src) {
+  ASSERT(CpuFeatures::IsEnabled(SSE2));
+  EnsureSpace ensure_space(this);
+  EMIT(0x66);
+  EMIT(0x0F);
+  EMIT(0x2E);
+  emit_sse_operand(dst, src);
+}
+
+
 void Assembler::roundsd(XMMRegister dst, XMMRegister src, RoundingMode mode) {
   ASSERT(CpuFeatures::IsEnabled(SSE4_1));
   EnsureSpace ensure_space(this);

src/ia32/assembler-ia32.h

@@ -987,6 +987,7 @@ class Assembler : public AssemblerBase {
   void andpd(XMMRegister dst, XMMRegister src);
 
   void ucomisd(XMMRegister dst, XMMRegister src);
+  void ucomisd(XMMRegister dst, const Operand& src);
 
   enum RoundingMode {
     kRoundToNearest = 0x0,

src/ia32/code-stubs-ia32.cc

@@ -3003,13 +3003,9 @@ void MathPowStub::Generate(MacroAssembler* masm) {
       // Check base in xmm1 for NaN or +/-Infinity
       const int kExponentShift = kBitsPerByte *
           (HeapNumber::kExponentOffset - HeapNumber::kMantissaOffset);
-      if (CpuFeatures::IsSupported(SSE4_1)) {
-        __ extractps(ecx, xmm1, kExponentShift);
-      } else {
       __ movsd(xmm4, xmm1);
       __ psrlq(xmm4, kExponentShift);
       __ movd(ecx, xmm4);
-      }
       __ and_(ecx, HeapNumber::kExponentMask);
       __ cmp(ecx, Immediate(HeapNumber::kExponentMask));
       __ j(equal, &generic_runtime);

src/ia32/lithium-codegen-ia32.cc

@@ -2938,9 +2938,28 @@ void LCodeGen::DoMathPowHalf(LUnaryMathOperation* instr) {
   XMMRegister xmm_scratch = xmm0;
   XMMRegister input_reg = ToDoubleRegister(instr->value());
   ASSERT(ToDoubleRegister(instr->result()).is(input_reg));
+
+  Label return_infinity, done;
+  // Check base for +/- infinity.
+  __ push(ecx);  // TODO(1848): reserve this register.
+  __ mov(ecx, factory()->infinity_value());
+  __ ucomisd(input_reg, FieldOperand(ecx, HeapNumber::kValueOffset));
+  __ j(equal, &return_infinity, Label::kNear);
+  __ xorps(xmm_scratch, xmm_scratch);
+  __ subsd(xmm_scratch, input_reg);
+  __ ucomisd(xmm_scratch, FieldOperand(ecx, HeapNumber::kValueOffset));
+  __ j(equal, &return_infinity, Label::kNear);
+
+  __ pop(ecx);
   __ xorps(xmm_scratch, xmm_scratch);
   __ addsd(input_reg, xmm_scratch);  // Convert -0 to +0.
   __ sqrtsd(input_reg, input_reg);
+  __ jmp(&done, Label::kNear);
+
+  __ bind(&return_infinity);
+  __ movdbl(input_reg, FieldOperand(ecx, HeapNumber::kValueOffset));
+  __ pop(ecx);
+  __ bind(&done);
 }
 
 

test/mjsunit/regress/regress-397.js

@@ -25,10 +25,19 @@
 // (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
 // See http://code.google.com/p/v8/issues/detail?id=397
 
-assertEquals("Infinity", String(Math.pow(Infinity, 0.5)));
-assertEquals(0, Math.pow(Infinity, -0.5));
 
-assertEquals("Infinity", String(Math.pow(-Infinity, 0.5)));
-assertEquals(0, Math.pow(-Infinity, -0.5));
+function test() {
+  assertEquals("Infinity", String(Math.pow(Infinity, 0.5)));
+  assertEquals(0, Math.pow(Infinity, -0.5));
+
+  assertEquals("Infinity", String(Math.pow(-Infinity, 0.5)));
+  assertEquals(0, Math.pow(-Infinity, -0.5));
+}
+
+test();
+test();
+%OptimizeFunctionOnNextCall(test);
+test();