[llvm] [InstCombine] Fold (sub (xor X, (sext C)), (sext C)) => (select C (neg X), X) (PR #79417)

[Kai Luo via llvm-commits]

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@@ -0,0 +1,19 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 4
+; RUN: opt < %s -passes=instcombine -S | FileCheck %s
+
+define  i64 @absdiff(i64 %0, i64 %1) {
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bzEq wrote:

> Does this pattern exist in some real-world applications?

Yes. We have observed this pattern in our internal workload.

https://github.com/llvm/llvm-project/pull/79417