Have LowerOperandForConstraint handle multiple character constraints.

Part of rdar://9119939

llvm-svn: 132510
diff --git a/llvm/lib/Target/PowerPC/PPCISelLowering.h b/llvm/lib/Target/PowerPC/PPCISelLowering.h
index 64a57a1..986b4e7 100644
--- a/llvm/lib/Target/PowerPC/PPCISelLowering.h
+++ b/llvm/lib/Target/PowerPC/PPCISelLowering.h
@@ -328,7 +328,7 @@
     /// LowerAsmOperandForConstraint - Lower the specified operand into the Ops
     /// vector.  If it is invalid, don't add anything to Ops.
     virtual void LowerAsmOperandForConstraint(SDValue Op,
-                                              char ConstraintLetter,
+                                              std::string &Constraint,
                                               std::vector<SDValue> &Ops,
                                               SelectionDAG &DAG) const;