[llvm] [MachinePipeliner] Remove UB from tests (NFC) (PR #123169)

[Ryotaro Kasuga via llvm-commits]

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@@ -10,21 +10,22 @@
 ; CHECK: = add([[REG1]],#8)
 
 ; Function Attrs: nounwind
-define ptr @f0(ptr nocapture readonly %a0, i32 %a1) #0 {
+define ptr @f0(ptr nocapture readonly %a0, i32 %a1, ptr noalias %p0, ptr noalias %p1, ptr noalias %p2) #0 {
 b0:
   %v0 = alloca [129 x i32], align 8
-  br i1 undef, label %b1, label %b3
+  %cond = freeze i1 poison
+  br i1 %cond, label %b1, label %b3
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kasuga-fj wrote:

Branching on an undef is UB.

https://github.com/llvm/llvm-project/pull/123169