PPC: Fix NaN Canonicalization.

src/ppc/macro-assembler-ppc.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <assert.h>  // For assert
 #include <limits.h>  // For LONG_MIN, LONG_MAX.
 
 #include "src/v8.h"
 
 #if V8_TARGET_ARCH_PPC
@@ skipping 584 matching lines @@
   // General purpose registers are pushed last on the stack.
   int doubles_size = DoubleRegister::NumAllocatableRegisters() * kDoubleSize;
   int register_offset = SafepointRegisterStackIndex(reg.code()) * kPointerSize;
   return MemOperand(sp, doubles_size + register_offset);
 }
 
 
 void MacroAssembler::CanonicalizeNaN(const DoubleRegister dst,
                                      const DoubleRegister src) {
   // Turn potential sNaN into qNaN.
-  fadd(dst, src, kDoubleRegZero);
+  fsub(dst, src, kDoubleRegZero);
 }
 
 
 void MacroAssembler::ConvertIntToDouble(Register src,
                                         DoubleRegister double_dst) {
   MovIntToDouble(double_dst, src, r0);
   fcfid(double_dst, double_dst);
 }
 
 
@@ skipping 3908 matching lines @@
   }
   if (mag.shift > 0) srawi(result, result, mag.shift);
   ExtractBit(r0, dividend, 31);
   add(result, result, r0);
 }
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_PPC