Avoid HeapObject check in HStoreNamedField.

src/x64/lithium-codegen-x64.cc

Index: src/x64/lithium-codegen-x64.cc
diff --git a/src/x64/lithium-codegen-x64.cc b/src/x64/lithium-codegen-x64.cc
index 5d72524cfe14f368dfefa8d67678c2a8cc5c3ea7..879fbb82dfcf5d342859776ab8ddee2b67db43a6 100644
--- a/src/x64/lithium-codegen-x64.cc
+++ b/src/x64/lithium-codegen-x64.cc
@@ -4000,29 +4000,12 @@ void LCodeGen::DoStoreNamedField(LStoreNamedField* instr) {
   }
 
   Register object = ToRegister(instr->object());
-  SmiCheck check_needed = hinstr->value()->IsHeapObject()
-                          ? OMIT_SMI_CHECK : INLINE_SMI_CHECK;
-
-  ASSERT(!(representation.IsSmi() &&
-           instr->value()->IsConstantOperand() &&
-           !IsInteger32Constant(LConstantOperand::cast(instr->value()))));
-  if (representation.IsHeapObject()) {
-    if (instr->value()->IsConstantOperand()) {
-      LConstantOperand* operand_value = LConstantOperand::cast(instr->value());
-      if (chunk_->LookupConstant(operand_value)->HasSmiValue()) {
-        DeoptimizeIf(no_condition, instr->environment());
-      }
-    } else {
-      if (!hinstr->value()->type().IsHeapObject()) {
-        Register value = ToRegister(instr->value());
-        Condition cc = masm()->CheckSmi(value);
-        DeoptimizeIf(cc, instr->environment());
+  __ AssertNotSmi(object);
 
-        // We know now that value is not a smi, so we can omit the check below.
-        check_needed = OMIT_SMI_CHECK;
-      }
-    }
-  } else if (representation.IsDouble()) {
+  ASSERT(!representation.IsSmi() ||
+         !instr->value()->IsConstantOperand() ||
+         IsInteger32Constant(LConstantOperand::cast(instr->value())));
+  if (representation.IsDouble()) {
     ASSERT(access.IsInobject());
     ASSERT(!hinstr->has_transition());
     ASSERT(!hinstr->NeedsWriteBarrier());
@@ -4107,7 +4090,7 @@ void LCodeGen::DoStoreNamedField(LStoreNamedField* instr) {
                         temp,
                         kSaveFPRegs,
                         EMIT_REMEMBERED_SET,
-                        check_needed);
+                        hinstr->SmiCheckForWriteBarrier());
   }
 }