[AArch64] Do not abort if overflow check does not use EQ or NE.

As suggested by Eli Friedman, instead of aborting if an overflow check
uses something other than SETEQ or SETNE, simply do not apply the
optimization.

Differential Revision: https://reviews.llvm.org/D39147

llvm-svn: 319837

llvm/lib/Target/AArch64/AArch64ISelLowering.cpp

@@ -4006,9 +4006,8 @@ SDValue AArch64TargetLowering::LowerBR_CC(SDValue Op, SelectionDAG &DAG) const {
 
   // Optimize {s|u}{add|sub|mul}.with.overflow feeding into a branch
   // instruction.
-  if (isOverflowIntrOpRes(LHS) && isOneConstant(RHS)) {
-    assert((CC == ISD::SETEQ || CC == ISD::SETNE) &&
-           "Unexpected condition code.");
+  if (isOverflowIntrOpRes(LHS) && isOneConstant(RHS) &&
+      (CC == ISD::SETEQ || CC == ISD::SETNE)) {
     // Only lower legal XALUO ops.
     if (!DAG.getTargetLoweringInfo().isTypeLegal(LHS->getValueType(0)))
       return SDValue();