[llvm] [ValueTracking] Add support for `sub` in `isKnownNonEqual` (PR #87704)

[Yingwei Zheng via llvm-commits]

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@@ -250,9 +250,7 @@ define <2 x i1> @sub_odd_poison(<2 x i8> %x) {
 
 define i1 @sub_even(i8 %x) {
 ; CHECK-LABEL: @sub_even(
-; CHECK-NEXT:    [[SUB:%.*]] = sub i8 2, [[X:%.*]]
-; CHECK-NEXT:    [[CMP:%.*]] = icmp ne i8 [[SUB]], [[X]]
-; CHECK-NEXT:    ret i1 [[CMP]]
+; CHECK-NEXT:    ret i1 true
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dtcxzyw wrote:

Miscompilation: https://alive2.llvm.org/ce/z/kmbPXT

https://github.com/llvm/llvm-project/pull/87704