Restore getInvertedCondCode() from the phased-out backend, fixing disassembly for NV

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@209803 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 3 insertions, 17 deletions

diff --git a/lib/Target/AArch64/Utils/AArch64BaseInfo.h b/lib/Target/AArch64/Utils/AArch64BaseInfo.h
index 9e4c389cc2..9d2ce21c96 100644
--- a/lib/Target/AArch64/Utils/AArch64BaseInfo.h
+++ b/lib/Target/AArch64/Utils/AArch64BaseInfo.h
@@ -233,23 +233,9 @@ inline static const char *getCondCodeName(CondCode Code) {
 }
 
 inline static CondCode getInvertedCondCode(CondCode Code) {
-  switch (Code) {
-  default: llvm_unreachable("Unknown condition code");
-  case EQ:  return NE;
-  case NE:  return EQ;
-  case HS:  return LO;
-  case LO:  return HS;
-  case MI:  return PL;
-  case PL:  return MI;
-  case VS:  return VC;
-  case VC:  return VS;
-  case HI:  return LS;
-  case LS:  return HI;
-  case GE:  return LT;
-  case LT:  return GE;
-  case GT:  return LE;
-  case LE:  return GT;
-  }
+  // To reverse a condition it's necessary to only invert the low bit:
+
+  return static_cast<CondCode>(static_cast<unsigned>(Code) ^ 0x1);
 }
 
 /// Given a condition code, return NZCV flags that would satisfy that condition.