[llvm] [SCEVExpander] Expand UDiv avoiding UB when in seq_min/max. (PR #92177)

[Nikita Popov via llvm-commits]

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@@ -676,7 +676,15 @@ Value *SCEVExpander::visitUDivExpr(const SCEVUDivExpr *S) {
                          SCEV::FlagAnyWrap, /*IsSafeToHoist*/ true);
   }
 
-  Value *RHS = expand(S->getRHS());
+  const SCEV *RHSExpr = S->getRHS();
+  Value *RHS = expand(RHSExpr);
+  if (SafeUDivMode &&
+      (!isa<SCEVConstant>(RHSExpr) || SE.isKnownNonZero(RHSExpr))) {
+    if (!isa<SCEVConstant>(S->getRHS()))
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nikic wrote:

This can now use the isGuaranteedNotToBePoison check instead.

https://github.com/llvm/llvm-project/pull/92177