[SelectionDAG] Pre-commit test for D124696. NFC

llvm/test/CodeGen/AArch64/pr55178.ll

@@ -0,0 +1,19 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc < %s -mtriple=aarch64-unknown-linux-gnu | FileCheck %s
+
+; This used to generate incorrect code because we sign extended
+; the undef to undef instead of to 0.
+
+define i1 @test14(i8 %X) {
+; CHECK-LABEL: test14:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    mov w8, #-113
+; CHECK-NEXT:    // kill: def $w0 killed $w0 def $x0
+; CHECK-NEXT:    lsl w8, w8, w0
+; CHECK-NEXT:    cmp w8, w8, sxtb
+; CHECK-NEXT:    cset w0, lt
+; CHECK-NEXT:    ret
+  %1 = shl i8 -113, %X
+  %cmp = icmp slt i8 undef, %1
+  ret i1 %cmp
+}