MIPS: Fix HInnerAllocatedObject to use an HValue for the offset.

src/mips/lithium-codegen-mips.cc

Index: src/mips/lithium-codegen-mips.cc
diff --git a/src/mips/lithium-codegen-mips.cc b/src/mips/lithium-codegen-mips.cc
index 3fb08ef7ce9b5f9bb16b001c26b706bc1b7797b8..56aac42663bbe03819d5202ff78557c6f20e49d6 100644
--- a/src/mips/lithium-codegen-mips.cc
+++ b/src/mips/lithium-codegen-mips.cc
@@ -4093,7 +4093,13 @@ void LCodeGen::DoStoreCodeEntry(LStoreCodeEntry* instr) {
 void LCodeGen::DoInnerAllocatedObject(LInnerAllocatedObject* instr) {
   Register result = ToRegister(instr->result());
   Register base = ToRegister(instr->base_object());
-  __ Addu(result, base, Operand(instr->offset()));
+  if (instr->offset()->IsConstantOperand()) {
+    LConstantOperand* offset = LConstantOperand::cast(instr->offset());
+    __ Addu(result, base, Operand(ToInteger32(offset)));
+  } else {
+    Register offset = ToRegister(instr->offset());
+    __ Addu(result, base, offset);
+  }
 }