[llvm] [LibCallShrinkWrap] Added ilogb in performCallErrors() (PR #122582)

[Yingwei Zheng via llvm-commits]

https://github.com/dtcxzyw requested changes to this pull request.

As @c8ef pointed out, we should fix it in `llvm::isMathLibCallNoop`. Constant folding is correct. But we have to prove that no errors occur in the call to eliminate the call to ilogb (See also https://en.cppreference.com/w/cpp/numeric/math/ilogb).

BTW, please pre-commit tests to demonstrate that your patch fixes the issue.
See also https://llvm.org/docs/InstCombineContributorGuide.html#precommit-tests.


https://github.com/llvm/llvm-project/pull/122582