Fix a regression from r138445.  If we're loading from the frame/base pointer
the tADDrSPi instruction can't be used.  Make sure we're updating the opcode
to tADDi3 in all cases.
rdar://10254707

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@141523 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/Thumb1RegisterInfo.cpp b/lib/Target/ARM/Thumb1RegisterInfo.cpp
index d6b0377..e8ed482 100644
--- a/lib/Target/ARM/Thumb1RegisterInfo.cpp
+++ b/lib/Target/ARM/Thumb1RegisterInfo.cpp
@@ -454,6 +454,7 @@
       // r0 = add sp, 255*4
       // r0 = add r0, (imm - 255*4)
       if (Opcode == ARM::tADDi3) {
+        MI.setDesc(TII.get(Opcode));
         removeOperands(MI, FrameRegIdx);
         MachineInstrBuilder MIB(&MI);
         AddDefaultPred(AddDefaultT1CC(MIB).addReg(FrameReg).addImm(Mask));