[x64] simply tweak materialization of float/double constants

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 877 matching lines @@
           break;
         case Constant::kHeapObject:
           __ Move(dst, src.ToHeapObject());
           break;
       }
       if (destination->IsStackSlot()) {
         __ movq(g.ToOperand(destination), kScratchRegister);
       }
     } else if (src.type() == Constant::kFloat32) {
       // TODO(turbofan): Can we do better here?
-      __ movl(kScratchRegister, Immediate(bit_cast<int32_t>(src.ToFloat32())));
+      uint32_t src_const = bit_cast<uint32_t>(src.ToFloat32());
       if (destination->IsDoubleRegister()) {
-        XMMRegister dst = g.ToDoubleRegister(destination);
-        __ movq(dst, kScratchRegister);
+        __ Move(g.ToDoubleRegister(destination), src_const);
       } else {
         DCHECK(destination->IsDoubleStackSlot());
         Operand dst = g.ToOperand(destination);
-        __ movl(dst, kScratchRegister);
+        __ movl(dst, Immediate(src_const));
       }
     } else {
       DCHECK_EQ(Constant::kFloat64, src.type());
-      __ movq(kScratchRegister, bit_cast<int64_t>(src.ToFloat64()));
+      uint64_t src_const = bit_cast<uint64_t>(src.ToFloat64());
       if (destination->IsDoubleRegister()) {
-        __ movq(g.ToDoubleRegister(destination), kScratchRegister);
+        __ Move(g.ToDoubleRegister(destination), src_const);
       } else {
         DCHECK(destination->IsDoubleStackSlot());
+        __ movq(kScratchRegister, src_const);
         __ movq(g.ToOperand(destination), kScratchRegister);
       }
     }
   } else if (source->IsDoubleRegister()) {
     XMMRegister src = g.ToDoubleRegister(source);
     if (destination->IsDoubleRegister()) {
       XMMRegister dst = g.ToDoubleRegister(destination);
       __ movsd(dst, src);
     } else {
       DCHECK(destination->IsDoubleStackSlot());
@@ skipping 78 matching lines @@
     }
   }
   MarkLazyDeoptSite();
 }
 
 #undef __
 
 }  // namespace internal
 }  // namespace compiler
 }  // namespace v8