[llvm] Reapply "[AArch64] Combine and and lsl into ubfiz" (#123356) (PR #124576)

[David Sherwood via llvm-commits]

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@@ -85,3 +85,20 @@ define i64 @lsl_zext_i16_i64(i16 %b) {
   %2 = shl i64 %1, 1
   ret i64 %2
 }
+
+; Regression test for:
+; https://github.com/llvm/llvm-project/pull/118974#issuecomment-2598521878
+; that exposed infinite loop in DAGCombiner.
+define void @_f(ptr %0, ptr %1, i64 %2) {
+; CHECK-LABEL: @_f
+  store i64 -2401053089408754003, ptr %1, align 8
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david-arm wrote:

Is it worth having a `CHECK-NOT: ubfiz` line here?

https://github.com/llvm/llvm-project/pull/124576