Fixing mozilla test failures regarding Math.pow.

src/x64/lithium-codegen-x64.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 2844 matching lines @@
 
   // Note that according to ECMA-262 15.8.2.13:
   // Math.pow(-Infinity, 0.5) == Infinity
   // Math.sqrt(-Infinity) == NaN
   Label done, sqrt;
   // Check base for -Infinity.  According to IEEE-754, double-precision
   // -Infinity has the highest 12 bits set and the lowest 52 bits cleared.
   __ movq(kScratchRegister, V8_INT64_C(0xFFF0000000000000), RelocInfo::NONE);
   __ movq(xmm_scratch, kScratchRegister);
   __ ucomisd(xmm_scratch, input_reg);
+  // Comparing -Infinity with NaN results in "unordered", which sets the
+  // zero flag as if both were equal.  However, it also sets the carry flag.
   __ j(not_equal, &sqrt, Label::kNear);
+  __ j(carry, &sqrt, Label::kNear);
   // If input is -Infinity, return Infinity.
   __ xorps(input_reg, input_reg);
   __ subsd(input_reg, xmm_scratch);
   __ jmp(&done, Label::kNear);
 
   // Square root.
   __ bind(&sqrt);
   __ xorps(xmm_scratch, xmm_scratch);
   __ addsd(input_reg, xmm_scratch);  // Convert -0 to +0.
   __ sqrtsd(input_reg, input_reg);
@@ skipping 1467 matching lines @@
   RegisterEnvironmentForDeoptimization(environment, Safepoint::kNoLazyDeopt);
   ASSERT(osr_pc_offset_ == -1);
   osr_pc_offset_ = masm()->pc_offset();
 }
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64