X64: Adding macro to load double from memory, and use SSE3 instruction if present.

src/x64/lithium-gap-resolver-x64.cc

Index: src/x64/lithium-gap-resolver-x64.cc
diff --git a/src/x64/lithium-gap-resolver-x64.cc b/src/x64/lithium-gap-resolver-x64.cc
index c3c617c456d03c40a6c1dcbc627116aae78115f1..c6d317ffe86b26d6e4fcb4d8337cb8dbd89a85b2 100644
--- a/src/x64/lithium-gap-resolver-x64.cc
+++ b/src/x64/lithium-gap-resolver-x64.cc
@@ -222,10 +222,10 @@ void LGapResolver::EmitMove(int index) {
   } else if (source->IsDoubleStackSlot()) {
     Operand src = cgen_->ToOperand(source);
     if (destination->IsDoubleRegister()) {
-      __ movsd(cgen_->ToDoubleRegister(destination), src);
+      __ LoadDbl(cgen_->ToDoubleRegister(destination), src);
     } else {
       ASSERT(destination->IsDoubleStackSlot());
-      __ movsd(xmm0, src);
+      __ LoadDbl(xmm0, src);
       __ movsd(cgen_->ToOperand(destination), xmm0);
     }
   } else {
@@ -264,7 +264,7 @@ void LGapResolver::EmitSwap(int index) {
     // Swap two stack slots or two double stack slots.
     Operand src = cgen_->ToOperand(source);
     Operand dst = cgen_->ToOperand(destination);
-    __ movsd(xmm0, src);
+    __ LoadDbl(xmm0, src);
     __ movq(kScratchRegister, dst);
     __ movsd(dst, xmm0);
     __ movq(src, kScratchRegister);
@@ -287,7 +287,7 @@ void LGapResolver::EmitSwap(int index) {
     LOperand* other = source->IsDoubleRegister() ? destination : source;
     ASSERT(other->IsDoubleStackSlot());
     Operand other_operand = cgen_->ToOperand(other);
-    __ movsd(xmm0, other_operand);
+    __ LoadDbl(xmm0, other_operand);
     __ movsd(other_operand, reg);
     __ movsd(reg, xmm0);