[llvm] [llvm] Remove `br i1 undef` from regression tests (PR #118419)

[Nuno Lopes via llvm-commits]

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@@ -1,14 +1,13 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
 ; RUN: opt < %s -passes=sccp -S | FileCheck %s
 
-; Branch on undef is UB, so the T block is never executed, and we can return
-; undef (IPSCCP would replace the block with unreachable).
-
-define i32 @foo() {
+define i32 @foo(i1 %arg) {
 ; CHECK-LABEL: @foo(
-; CHECK-NEXT:    unreachable
+; CHECK-NEXT:    br i1 [[ARG:%.*]], label [[T:%.*]], label [[T]]
+; CHECK:       T:
+; CHECK-NEXT:    ret i32 1
 ;
-  br i1 undef, label %T, label %T
+  br i1 %arg, label %T, label %T
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nunoplopes wrote:

leave this one as poison to retain the spirit of the test

https://github.com/llvm/llvm-project/pull/118419