[llvm] [LLVM][SCEV] udiv (mul nuw a, vscale), (mul nuw b, vscale) -> udiv a, b (PR #157836)

[Paul Walker via llvm-commits]

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@@ -188,3 +188,43 @@ loop:
 exit:
   ret void
 }
+
+define noundef i64 @udiv_mul_common_vscale_factor(i64 %a, i64 %b) {
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paulwalker-arm wrote:

I added `noundef` because without it SCEV seems to loose the wrap flags for one of the multiplies.

https://github.com/llvm/llvm-project/pull/157836