Update the gap resolver to support Smi constants.

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 22183a2f8d781df32de5d25b217448149c583c0b..fd74e0aacd9ed0562daea799d6baacabc8661cef 100644
--- a/src/x64/lithium-gap-resolver-x64.cc
+++ b/src/x64/lithium-gap-resolver-x64.cc
@@ -195,7 +195,9 @@ void LGapResolver::EmitMove(int index) {
     LConstantOperand* constant_source = LConstantOperand::cast(source);
     if (destination->IsRegister()) {
       Register dst = cgen_->ToRegister(destination);
-      if (cgen_->IsInteger32Constant(constant_source)) {
+      if (cgen_->IsSmiConstant(constant_source)) {
+        __ Move(dst, cgen_->ToSmi(constant_source));
+      } else if (cgen_->IsInteger32Constant(constant_source)) {
         __ movl(dst, Immediate(cgen_->ToInteger32(constant_source)));
       } else {
         __ LoadObject(dst, cgen_->ToHandle(constant_source));
@@ -203,7 +205,9 @@ void LGapResolver::EmitMove(int index) {
     } else {
       ASSERT(destination->IsStackSlot());
       Operand dst = cgen_->ToOperand(destination);
-      if (cgen_->IsInteger32Constant(constant_source)) {
+      if (cgen_->IsSmiConstant(constant_source)) {
+        __ Move(dst, cgen_->ToSmi(constant_source));
+      } else if (cgen_->IsInteger32Constant(constant_source)) {
         // Zero top 32 bits of a 64 bit spill slot that holds a 32 bit untagged
         // value.
         __ movq(dst, Immediate(cgen_->ToInteger32(constant_source)));