[x64] Smi zero can be used as an immediate.

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

Index: src/compiler/x64/code-generator-x64.cc
diff --git a/src/compiler/x64/code-generator-x64.cc b/src/compiler/x64/code-generator-x64.cc
index 2105d66e4714ba709efc1c1efca36ef31625bf1a..b4d200b39d8056c9b05a83eb7a7a110a94caed0a 100644
--- a/src/compiler/x64/code-generator-x64.cc
+++ b/src/compiler/x64/code-generator-x64.cc
@@ -38,7 +38,12 @@ class X64OperandConverter : public InstructionOperandConverter {
   Operand OutputOperand() { return ToOperand(instr_->Output()); }
 
   Immediate ToImmediate(InstructionOperand* operand) {
-    return Immediate(ToConstant(operand).ToInt32());
+    Constant constant = ToConstant(operand);
+    if (constant.type() == Constant::kFloat64) {
+      DCHECK_EQ(0, bit_cast<int64_t>(constant.ToFloat64()));
+      return Immediate(0);
+    }
+    return Immediate(constant.ToInt32());
   }
 
   Operand ToOperand(InstructionOperand* op, int extra = 0) {