PPC conditional branch predicate does not change after isel.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@37893 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/PowerPC/PPCInstrInfo.td b/lib/Target/PowerPC/PPCInstrInfo.td
index bbddad2..4ffde0a 100644
--- a/lib/Target/PowerPC/PPCInstrInfo.td
+++ b/lib/Target/PowerPC/PPCInstrInfo.td
@@ -272,7 +272,8 @@
 
 // PowerPC Predicate operand.  20 = (0<<5)|20 = always, CR0 is a dummy reg
 // that doesn't matter.
-def pred : PredicateOperand<OtherVT, (ops imm, CRRC), (ops (i32 20), CR0)> {
+def pred : ImmutablePredicateOperand<OtherVT, (ops imm, CRRC),
+                                              (ops (i32 20), CR0)> {
   let PrintMethod = "printPredicateOperand";
 }