X64 Crankshaft: Fix unrestored context register in Math.power.

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 2545 matching lines @@
 
     __ bind(&call);
     __ PrepareCallCFunction(2);
     // Move arguments to correct registers xmm0 and xmm1.
     __ movsd(xmm0, left_reg);
     // Right argument is already in xmm1.
     __ CallCFunction(ExternalReference::power_double_double_function(), 2);
   }
   // Return value is in xmm0.
   __ movsd(result_reg, xmm0);
+  // Restore context register.
+  __ movq(rsi, Operand(rbp, StandardFrameConstants::kContextOffset));
 }
 
 
 void LCodeGen::DoMathLog(LUnaryMathOperation* instr) {
   ASSERT(ToDoubleRegister(instr->result()).is(xmm1));
   TranscendentalCacheStub stub(TranscendentalCache::LOG,
                                TranscendentalCacheStub::UNTAGGED);
   CallCode(stub.GetCode(), RelocInfo::CODE_TARGET, instr);
 }
 
@@ skipping 1078 matching lines @@
   RegisterEnvironmentForDeoptimization(environment);
   ASSERT(osr_pc_offset_ == -1);
   osr_pc_offset_ = masm()->pc_offset();
 }
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64