[llvm] [InstCombine] Fold `sext(A < B) + zext(A > B)` into `ucmp/scmp(A, B)` (PR #103833)

[Yingwei Zheng via llvm-commits]

================
@@ -1277,8 +1277,8 @@ define <2 x i8> @ashr_add_commute(<2 x i1> %x, <2 x i1> %y) {
 
 define i32 @cmp_math(i32 %x, i32 %y) {
 ; CHECK-LABEL: @cmp_math(
-; CHECK-NEXT:    [[LT:%.*]] = icmp ult i32 [[X:%.*]], [[Y:%.*]]
-; CHECK-NEXT:    [[R:%.*]] = zext i1 [[LT]] to i32
+; CHECK-NEXT:    [[S:%.*]] = call i32 @llvm.ucmp.i32.i32(i32 [[X:%.*]], i32 [[Y:%.*]])
+; CHECK-NEXT:    [[R:%.*]] = lshr i32 [[S]], 31
----------------
dtcxzyw wrote:

Regression.

https://github.com/llvm/llvm-project/pull/103833