[llvm] [SCEV] Fix NSW flag propagation in getGEPExpr, getMulExpr, and getAddExpr (PR #155145)

[via llvm-commits]

github-actions[bot] wrote:

<!--LLVM CODE FORMAT COMMENT: {undef deprecator}-->


:warning: undef deprecator found issues in your code. :warning:

<details>
<summary>
You can test this locally with the following command:
</summary>

``````````bash
git diff -U0 --pickaxe-regex -S '([^a-zA-Z0-9#_-]undef[^a-zA-Z0-9_-]|UndefValue::get)' 'HEAD~1' HEAD llvm/test/Analysis/DependenceAnalysis/scev-nsw-flags-enable-analysis.ll llvm/test/Analysis/LoopAccessAnalysis/waw-negative-dependence.ll llvm/test/Analysis/ScalarEvolution/gep-nsw-flag-preservation.ll llvm/lib/Analysis/LoopAccessAnalysis.cpp llvm/lib/Analysis/ScalarEvolution.cpp llvm/test/Analysis/Delinearization/a.ll llvm/test/Analysis/Delinearization/constant_functions_multi_dim.ll llvm/test/Analysis/Delinearization/fixed_size_array.ll llvm/test/Analysis/Delinearization/himeno_1.ll llvm/test/Analysis/Delinearization/himeno_2.ll llvm/test/Analysis/Delinearization/iv_times_constant_in_subscript.ll llvm/test/Analysis/Delinearization/multidim_ivs_and_integer_offsets_3d.ll llvm/test/Analysis/Delinearization/multidim_ivs_and_integer_offsets_nts_3d.ll llvm/test/Analysis/Delinearization/multidim_ivs_and_parameteric_offsets_3d.ll llvm/test/Analysis/Delinearization/multidim_only_ivs_2d.ll llvm/test/Analysis/Delinearization/multidim_only_ivs_2d_nested.ll llvm/test/Analysis/Delinearization/multidim_only_ivs_3d.ll llvm/test/Analysis/Delinearization/multidim_only_ivs_3d_cast.ll llvm/test/Analysis/Delinearization/multidim_two_accesses_different_delinearization.ll llvm/test/Analysis/DependenceAnalysis/DADelin.ll llvm/test/Analysis/LoopAccessAnalysis/depend_diff_types.ll llvm/test/Analysis/LoopAccessAnalysis/different-access-types-rt-checks.ll llvm/test/Analysis/LoopAccessAnalysis/evaluate-at-symbolic-max-backedge-taken-count-may-wrap.ll llvm/test/Analysis/LoopAccessAnalysis/forward-loop-carried.ll llvm/test/Analysis/LoopAccessAnalysis/forward-loop-independent.ll llvm/test/Analysis/LoopAccessAnalysis/loops-with-indirect-reads-and-writes.ll llvm/test/Analysis/LoopAccessAnalysis/number-of-memchecks.ll llvm/test/Analysis/LoopAccessAnalysis/retry-runtime-checks-after-dependence-analysis-forked-pointers.ll llvm/test/Analysis/LoopAccessAnalysis/retry-runtime-checks-after-dependence-analysis.ll llvm/test/Analysis/LoopAccessAnalysis/symbolic-stride.ll llvm/test/Analysis/ScalarEvolution/different-loops-recs.ll llvm/test/Analysis/ScalarEvolution/flags-from-poison.ll llvm/test/Analysis/ScalarEvolution/max-backedge-taken-count-guard-info.ll llvm/test/Analysis/ScalarEvolution/max-expr-cache.ll llvm/test/Analysis/ScalarEvolution/nsw.ll llvm/test/Analysis/ScalarEvolution/ptrtoint.ll llvm/test/Analysis/ScalarEvolution/trip-count-scalable-stride.ll llvm/test/Transforms/LoopIdiom/memset-runtime-debug.ll llvm/test/Transforms/LoopStrengthReduce/lsr-term-fold-negative-testcase.ll llvm/test/Transforms/LoopUnrollAndJam/unroll-and-jam.ll llvm/test/Transforms/LoopVectorize/AArch64/sve-interleaved-accesses.ll llvm/test/Transforms/LoopVectorize/interleaved-accesses.ll
``````````

</details>


The following files introduce new uses of undef:
 - llvm/test/Analysis/ScalarEvolution/max-expr-cache.ll

[Undef](https://llvm.org/docs/LangRef.html#undefined-values) is now deprecated and should only be used in the rare cases where no replacement is possible. For example, a load of uninitialized memory yields `undef`. You should use `poison` values for placeholders instead.

In tests, avoid using `undef` and having tests that trigger undefined behavior. If you need an operand with some unimportant value, you can add a new argument to the function and use that instead.

For example, this is considered a bad practice:
```llvm
define void @fn() {
  ...
  br i1 undef, ...
}
```

Please use the following instead:
```llvm
define void @fn(i1 %cond) {
  ...
  br i1 %cond, ...
}
```

Please refer to the [Undefined Behavior Manual](https://llvm.org/docs/UndefinedBehavior.html) for more information.



https://github.com/llvm/llvm-project/pull/155145