[llvm] [llvm] Remove `br i1 undef` from regression tests (PR #116161)

[Lee Wei via llvm-commits]

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@@ -50,13 +53,13 @@ entry:
   br label %while.cond
 
 while.cond:
-  br i1 undef, label %while.end, label %while.body
+  br i1 %arg, label %while.end, label %while.body
 
 while.body:                                       ; preds = %while.cond
-  br i1 undef, label %if.then165, label %while.cond
+  br i1 %arg, label %if.then165, label %while.cond
 
 if.then165:                                       ; preds = %while.body
-  br i1 undef, label %while.cond, label %for.body.lr.ph.i81
+  br i1 %arg, label %while.cond, label %for.body.lr.ph.i81
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leewei05 wrote:

@nunoplopes A question here, for this case https://alive2.llvm.org/ce/z/RvwJpB
1. Does infinite loop be seen as Undefined Behavior for Alive2? I remembered John told me that Alive2 unrolls loops twice and after that Alive2 just gives up.

There are two `icmp undef` cases here. The first one was `icmp ult i32 0, undef`, so I replaced it with `false`. The second one was ` icmp ult i32 %inc.i125, undef`, so I replaced it with `%arg`.

https://github.com/llvm/llvm-project/pull/116161