Add support for adding an external and a tagged pointer

src/mips/lithium-mips.cc

Index: src/mips/lithium-mips.cc
diff --git a/src/mips/lithium-mips.cc b/src/mips/lithium-mips.cc
index 3f0e7bfd27a0cffabfcb8f1564efcf2418f1529f..d24349ab8f8ba8e68ad063e9845aef58c148dc7b 100644
--- a/src/mips/lithium-mips.cc
+++ b/src/mips/lithium-mips.cc
@@ -1623,7 +1623,7 @@ LInstruction* LChunkBuilder::DoAdd(HAdd* instr) {
     return result;
   } else if (instr->representation().IsExternal()) {
     DCHECK(instr->left()->representation().IsExternal());

[Jarin, 2015/07/20 14:51:24]

You can leave out DCHECK(instr->left()->representation().IsExternal()), it is
covered by IsConsistentExternalRepresentation.

-    DCHECK(instr->right()->representation().IsInteger32());
+    DCHECK(instr->IsConsistentExternalRepresentation());
     DCHECK(!instr->CheckFlag(HValue::kCanOverflow));
     LOperand* left = UseRegisterAtStart(instr->left());
     LOperand* right = UseOrConstantAtStart(instr->right());