Use a fixed input register where we require a byte register.

src/ia32/lithium-ia32.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1887 matching lines @@
 LInstruction* LChunkBuilder::DoStoreKeyedSpecializedArrayElement(
     HStoreKeyedSpecializedArrayElement* instr) {
   Representation representation(instr->value()->representation());
   ExternalArrayType array_type = instr->array_type();
   ASSERT((representation.IsInteger32() && array_type != kExternalFloatArray) ||
          (representation.IsDouble() && array_type == kExternalFloatArray));
   ASSERT(instr->external_pointer()->representation().IsExternal());
   ASSERT(instr->key()->representation().IsInteger32());
 
   LOperand* external_pointer = UseRegister(instr->external_pointer());
-  LOperand* val = UseRegister(instr->value());
   LOperand* key = UseRegister(instr->key());
   LOperand* temp = NULL;
 
   if (array_type == kExternalPixelArray) {
     // The generated code for pixel array stores requires that the clamped value
     // is in a byte register. eax is an arbitrary choice to satisfy this
     // requirement.
     temp = FixedTemp(eax);
   }
 
+  LOperand* val = NULL;
+  if (array_type == kExternalByteArray ||
+      array_type == kExternalUnsignedByteArray) {
+    // We need a byte register in this case for the value.
+    val = UseFixed(instr->value(), eax);
+  } else {
+    val = UseRegister(instr->value());
+  }
+
   return new LStoreKeyedSpecializedArrayElement(external_pointer,
                                                 key,
                                                 val,
                                                 temp);
 }
 
 
 LInstruction* LChunkBuilder::DoStoreKeyedGeneric(HStoreKeyedGeneric* instr) {
   LOperand* context = UseFixed(instr->context(), esi);
   LOperand* object = UseFixed(instr->object(), edx);
@@ skipping 212 matching lines @@
 LInstruction* LChunkBuilder::DoLeaveInlined(HLeaveInlined* instr) {
   HEnvironment* outer = current_block_->last_environment()->outer();
   current_block_->UpdateEnvironment(outer);
   return NULL;
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32