[llvm] [InstCombine] Fix UB in align-assume check (PR #201985)

[Sudharsan Veeravalli via llvm-commits]

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@@ -257,6 +270,16 @@ define ptr @assume_align_1(ptr %p) {
   ret ptr %p
 }
 
+define ptr @redundant_assume_align_null() {
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svs-quic wrote:

This test was taken from the test above. I've made it void now.

https://github.com/llvm/llvm-project/pull/201985