Move PPC getSwappedPredicate for reuse

The getSwappedPredicate function can be used in other places (such as in
improvements to the PPCCTRLoops pass). Instead of trapping it as a static
function in PPCInstrInfo, move it into PPCPredicates with other
predicate-related things.

No functionality change intended.

llvm-svn: 179926
diff --git a/llvm/lib/Target/PowerPC/MCTargetDesc/PPCPredicates.h b/llvm/lib/Target/PowerPC/MCTargetDesc/PPCPredicates.h
index ad2b018..444758c 100644
--- a/llvm/lib/Target/PowerPC/MCTargetDesc/PPCPredicates.h
+++ b/llvm/lib/Target/PowerPC/MCTargetDesc/PPCPredicates.h
@@ -37,6 +37,10 @@
   
   /// Invert the specified predicate.  != -> ==, < -> >=.
   Predicate InvertPredicate(Predicate Opcode);
+
+  /// Assume the condition register is set by MI(a,b), return the predicate if
+  /// we modify the instructions such that condition register is set by MI(b,a).
+  Predicate getSwappedPredicate(Predicate Opcode);
 }
 }