Fix more of PR8825. Now all of CodeGen/ARM passes with VerifyCoalescing turned on.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131578 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/ARMLoadStoreOptimizer.cpp b/lib/Target/ARM/ARMLoadStoreOptimizer.cpp
index df89fad..8b9a82e 100644
--- a/lib/Target/ARM/ARMLoadStoreOptimizer.cpp
+++ b/lib/Target/ARM/ARMLoadStoreOptimizer.cpp
@@ -1672,10 +1672,14 @@
           Ops.pop_back();
           Ops.pop_back();
 
+          const TargetInstrDesc &TID = TII->get(NewOpc);
+          const TargetRegisterClass *TRC = TID.OpInfo[0].getRegClass(TRI);
+          MRI->constrainRegClass(EvenReg, TRC);
+          MRI->constrainRegClass(OddReg, TRC);
+
           // Form the pair instruction.
           if (isLd) {
-            MachineInstrBuilder MIB = BuildMI(*MBB, InsertPos,
-                                              dl, TII->get(NewOpc))
+            MachineInstrBuilder MIB = BuildMI(*MBB, InsertPos, dl, TID)
               .addReg(EvenReg, RegState::Define)
               .addReg(OddReg, RegState::Define)
               .addReg(BaseReg);
@@ -1687,8 +1691,7 @@
             MIB.addImm(Offset).addImm(Pred).addReg(PredReg);
             ++NumLDRDFormed;
           } else {
-            MachineInstrBuilder MIB = BuildMI(*MBB, InsertPos,
-                                              dl, TII->get(NewOpc))
+            MachineInstrBuilder MIB = BuildMI(*MBB, InsertPos, dl, TID)
               .addReg(EvenReg)
               .addReg(OddReg)
               .addReg(BaseReg);