[PATCH] [mips] Mark aggregates returned in registers with the 'inreg' attribute.

[Simon Atanasyan]

LGTM

================
Comment at: lib/CodeGen/TargetInfo.cpp:5535
@@ -5534,2 +5534,3 @@
 
       // O32 returns integer vectors in registers.
+      if (IsO32 && RetTy->isVectorType() &&
----------------
Does it have a sense to join two `if` conditions below into the single one?

```
if (!IsO32 || (RetTy->isVectorType() && !RetTy->hasFloatingRepresentation())) {
  ABIArgInfo ArgInfo = ABIArgInfo::getDirect(returnAggregateInRegs(RetTy, Size));
  ArgInfo.setInReg(true);
  return ArgInfo;
}
```

http://reviews.llvm.org/D5005