[llvm] [SCEVExpander] Don't expand a UDiv with a possibly-poison divisor (PR #202378)

[via llvm-commits]

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@@ -0,0 +1,44 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -S -passes=indvars < %s | FileCheck %s
+
+; Reduced from https://github.com/llvm/llvm-project/issues/202028.
+
+target triple = "x86_64-unknown-linux-gnu"
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lijinpei wrote:

`X86TTIImpl::getArithmeticInstrCost` reports 1 for udiv/urem , while `TargetTransformInfoImplBase::getArithmeticInstrCost`, reports 4. `rewriteLoopExitValues` needs the cost to be cheap to hoist it.
Now I replaced it with `-replexitval=always`.

https://github.com/llvm/llvm-project/pull/202378