[llvm] [DAGCombiner] add fold (xor (smin(x, C), C)) and fold (xor (smax(x, C), C)) (PR #155141)

[guan jian via llvm-commits]

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@@ -0,0 +1,278 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc < %s -mtriple=aarch64-unknown-unknown -mcpu=cortex-a53 | FileCheck %s
+
+; Test for DAGCombiner optimization: fold (xor (smin(x, C), C)) -> select (x < C), xor (x, C), 0
+
+define i64 @test_smin_neg_one(i64 %a) {
+; CHECK-LABEL: test_smin_neg_one:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    cmn x0, #1
+; CHECK-NEXT:    csinv x0, xzr, x0, ge
+; CHECK-NEXT:    ret
+  %1 = tail call i64 @llvm.smin.i64(i64 %a, i64 -1)
+  %retval.0 = xor i64 %1, -1
+  ret i64 %retval.0
+}
+
+define i64 @test_smin_zero(i64 %a) {
+; CHECK-LABEL: test_smin_zero:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    and x0, x0, x0, asr #63
+; CHECK-NEXT:    ret
+  %1 = tail call i64 @llvm.smin.i64(i64 %a, i64 0)
+  %retval.0 = xor i64 %1, 0
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rez5427 wrote:

removed

https://github.com/llvm/llvm-project/pull/155141