[mips] Correct 128-bit shifts on 64-bit targets.

Summary:
The existing code was correct for 32-bit GPR's but not 64-bit GPR's. It now
accounts for both cases.

Reviewers: vkalintiris

Reviewed By: vkalintiris

Subscribers: llvm-commits, mohit.bhakkad, sagar

Differential Revision: http://reviews.llvm.org/D9337

llvm-svn: 236099
diff --git a/llvm/lib/Target/Mips/MipsISelLowering.cpp b/llvm/lib/Target/Mips/MipsISelLowering.cpp
index 92abe0e..675e3a6 100644
--- a/llvm/lib/Target/Mips/MipsISelLowering.cpp
+++ b/llvm/lib/Target/Mips/MipsISelLowering.cpp
@@ -2074,7 +2074,7 @@
   SDValue Or = DAG.getNode(ISD::OR, DL, VT, ShiftLeftHi, ShiftRightLo);
   SDValue ShiftLeftLo = DAG.getNode(ISD::SHL, DL, VT, Lo, Shamt);
   SDValue Cond = DAG.getNode(ISD::AND, DL, MVT::i32, Shamt,
-                             DAG.getConstant(0x20, DL, MVT::i32));
+                             DAG.getConstant(VT.getSizeInBits(), DL, MVT::i32));
   Lo = DAG.getNode(ISD::SELECT, DL, VT, Cond,
                    DAG.getConstant(0, DL, VT), ShiftLeftLo);
   Hi = DAG.getNode(ISD::SELECT, DL, VT, Cond, ShiftLeftLo, Or);
@@ -2113,12 +2113,12 @@
   SDValue ShiftRightHi = DAG.getNode(IsSRA ? ISD::SRA : ISD::SRL,
                                      DL, VT, Hi, Shamt);
   SDValue Cond = DAG.getNode(ISD::AND, DL, MVT::i32, Shamt,
-                             DAG.getConstant(0x20, DL, MVT::i32));
-  SDValue Shift31 = DAG.getNode(ISD::SRA, DL, VT, Hi,
-                                DAG.getConstant(31, DL, VT));
+                             DAG.getConstant(VT.getSizeInBits(), DL, MVT::i32));
+  SDValue Ext = DAG.getNode(ISD::SRA, DL, VT, Hi,
+                            DAG.getConstant(VT.getSizeInBits() - 1, DL, VT));
   Lo = DAG.getNode(ISD::SELECT, DL, VT, Cond, ShiftRightHi, Or);
   Hi = DAG.getNode(ISD::SELECT, DL, VT, Cond,
-                   IsSRA ? Shift31 : DAG.getConstant(0, DL, VT), ShiftRightHi);
+                   IsSRA ? Ext : DAG.getConstant(0, DL, VT), ShiftRightHi);
 
   SDValue Ops[2] = {Lo, Hi};
   return DAG.getMergeValues(Ops, DL);