X87: Bugfix: assert in lithium compile for LMaybeGrowElements.

src/crankshaft/x87/lithium-codegen-x87.cc

 // Copyright 2012 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.
 
 #if V8_TARGET_ARCH_X87
 
 #include "src/crankshaft/x87/lithium-codegen-x87.h"
 
 #include "src/base/bits.h"
 #include "src/code-factory.h"
@@ skipping 4345 matching lines @@
   {
     PushSafepointRegistersScope scope(this);
     if (instr->object()->IsRegister()) {
       __ Move(result, ToRegister(instr->object()));
     } else {
       __ mov(result, ToOperand(instr->object()));
     }
 
     LOperand* key = instr->key();
     if (key->IsConstantOperand()) {
-      __ mov(ebx, ToImmediate(key, Representation::Smi()));
+      LConstantOperand* constant_key = LConstantOperand::cast(key);
+      int32_t int_key = ToInteger32(constant_key);
+      if (Smi::IsValid(int_key)) {
+        __ mov(ebx, Immediate(Smi::FromInt(int_key)));
+      } else {
+        // We should never get here at runtime because there is a smi check on
+        // the key before this point.
+        __ int3();
+      }
     } else {
       __ Move(ebx, ToRegister(key));
       __ SmiTag(ebx);
     }
 
     GrowArrayElementsStub stub(isolate(), instr->hydrogen()->is_js_array(),
                                instr->hydrogen()->kind());
     __ CallStub(&stub);
     RecordSafepointWithLazyDeopt(
         instr, RECORD_SAFEPOINT_WITH_REGISTERS_AND_NO_ARGUMENTS);
@@ skipping 1448 matching lines @@
   __ bind(deferred->exit());
   __ bind(&done);
 }
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X87