Support double allocations when folding allocation.

src/ia32/lithium-codegen-ia32.cc

 // Copyright 2012 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 4316 matching lines @@
 
 
 void LCodeGen::DoCallRuntime(LCallRuntime* instr) {
   CallRuntime(instr->function(), instr->arity(), instr);
 }
 
 
 void LCodeGen::DoInnerAllocatedObject(LInnerAllocatedObject* instr) {
   Register result = ToRegister(instr->result());
   Register base = ToRegister(instr->base_object());
-  __ lea(result, Operand(base, instr->offset()));
+  int offset = instr->offset();
+  if (instr->hydrogen()->MustAllocateDoubleAligned()) {
+    ASSERT(kPointerAlignment * 2 == kDoubleAlignment);
+    Label aligned;
+    __ test(base, Immediate(kDoubleAlignmentMask));
+    __ j(zero, &aligned, Label::kNear);

[Michael Starzinger, 2013/07/22 19:46:56]

This is a NOP. The jump at runtime does not affect the modification of offset at
compile time. Also a test+jump seems like overkill.

+    offset += (kDoubleSize / 2);
+    __ bind(&aligned);
+  }
+  __ lea(result, Operand(base, offset));
 }
 
 
 void LCodeGen::DoStoreNamedField(LStoreNamedField* instr) {
   Representation representation = instr->representation();
 
   Register object = ToRegister(instr->object());
   HObjectAccess access = instr->hydrogen()->access();
   int offset = access.offset();
 
@@ skipping 2153 matching lines @@
                               FixedArray::kHeaderSize - kPointerSize));
   __ bind(&done);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32