TF: Clear upper bits of ConvertFloat64ToUint32 because Win64.

src/compiler/x64/code-generator-x64.cc

 // Copyright 2013 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 "src/compiler/code-generator.h"
 
 #include "src/compiler/code-generator-impl.h"
 #include "src/compiler/gap-resolver.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/node-properties-inl.h"
@@ skipping 478 matching lines @@
       if (input.type == kDoubleRegister) {
         __ cvttsd2si(i.OutputRegister(), input.double_reg);
       } else {
         __ cvttsd2si(i.OutputRegister(), input.operand);
       }
       break;
     }
     case kSSEFloat64ToUint32: {
       // TODO(turbofan): X64 SSE cvttsd2siq should support operands.
       __ cvttsd2siq(i.OutputRegister(), i.InputDoubleRegister(0));
+      __ andl(i.OutputRegister(), i.OutputRegister());  // clear upper bits.
+      // TODO(turbofan): generated code should not look at the upper 32 bits
+      // of the result, but those bits could escape to the outside world.
       break;
     }
     case kSSEInt32ToFloat64: {
       RegisterOrOperand input = i.InputRegisterOrOperand(0);
       if (input.type == kRegister) {
         __ cvtlsi2sd(i.OutputDoubleRegister(), input.reg);
       } else {
         __ cvtlsi2sd(i.OutputDoubleRegister(), input.operand);
       }
       break;
@@ skipping 465 matching lines @@
     return false;
   }
   return *(code->instruction_start() + start_pc) ==
          v8::internal::Assembler::kNopByte;
 }
 
 #endif
 }
 }
 }  // namespace v8::internal::compiler