[llvm] [LV][NFC] Change undef to poison in most tests (PR #163525)

[Florian Hahn via llvm-commits]

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@@ -468,7 +468,7 @@ entry:
 for.body:
   %tmp0 = phi i64 [ %tmp6, %for.inc ], [ 0, %entry ]
   %tmp1 = phi i64 [ %tmp7, %for.inc ], [ 1000, %entry ]
-  %tmp2 = getelementptr i8, ptr undef, i64 %tmp0
+  %tmp2 = getelementptr i8, ptr poison, i64 %tmp0
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fhahn wrote:

Better to change those to use a pointer argument, to avoid unconditional UB in the test. 

https://github.com/llvm/llvm-project/pull/163525