Merge r6573 to 3.0 branch. This is a fix for issue 1088, Math.pow(-0, 0.5).

src/ia32/lithium-codegen-ia32.cc

 // Copyright 2011 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:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 2370 matching lines @@
 
 void LCodeGen::DoMathPowHalf(LUnaryMathOperation* instr) {
   XMMRegister xmm_scratch = xmm0;
   XMMRegister input_reg = ToDoubleRegister(instr->InputAt(0));
   ASSERT(ToDoubleRegister(instr->result()).is(input_reg));
   ExternalReference negative_infinity =
       ExternalReference::address_of_negative_infinity();
   __ 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);
 }
 
 
 void LCodeGen::DoPower(LPower* instr) {
   LOperand* left = instr->InputAt(0);
   LOperand* right = instr->InputAt(1);
   DoubleRegister result_reg = ToDoubleRegister(instr->result());
   Representation exponent_type = instr->hydrogen()->right()->representation();
   if (exponent_type.IsDouble()) {
@@ skipping 1205 matching lines @@
   ASSERT(osr_pc_offset_ == -1);
   osr_pc_offset_ = masm()->pc_offset();
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32