[llvm] [LV] Rewrite UDiv A, B -> UDiv A, UMax(B, 1) in trip counts if needed. (PR #92177)

[Florian Hahn via llvm-commits]

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@@ -1358,11 +1364,13 @@ Value *SCEVExpander::visitSignExtendExpr(const SCEVSignExtendExpr *S) {
 Value *SCEVExpander::expandMinMaxExpr(const SCEVNAryExpr *S,
                                       Intrinsic::ID IntrinID, Twine Name,
                                       bool IsSequential) {
+  SafeUDivMode = true;
   Value *LHS = expand(S->getOperand(S->getNumOperands() - 1));
   Type *Ty = LHS->getType();
   if (IsSequential)
     LHS = Builder.CreateFreeze(LHS);
   for (int i = S->getNumOperands() - 2; i >= 0; --i) {
+    SafeUDivMode = i != 0;
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fhahn wrote:

Updated to save the initial mode, and updated the code to not set it to false if it was already set.

And restored the original value on exit.

The earlier version was also enabling it if IsSequential was false. Also fixed

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