[PATCH] D72975: [PatternMatch] Add m_APInt/m_APFloat matchers accepting undef

[Nikita Popov via Phabricator via llvm-commits]

nikic created this revision.
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The current `m_APInt()` and `m_APFloat()` matchers do not accept splats that include undefs (unlike `m_Zero()` and other matchers for specific values). We can't simply change the default behavior, as there are existing transforms that would not be safe with undefs.

For this reason, I'm introducing new `m_APIntAllowUndef()` and `m_APFloatAllowUndef()` matchers, that allow splats with undefs. Additionally, `m_APIntForbidUndef()` and `m_APFloatForbidUndef()` are added. These have the same behavior as the existing `m_APInt()` and `m_APFloat()`, but serve as an explicit indication that undefs were explicitly considered and found unsound for this transform. This helps distinguish them from existing uses of `m_APInt()` where we do not know whether undefs can or cannot be allowed without additional review.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D72975

Files:
  llvm/include/llvm/IR/PatternMatch.h
  llvm/unittests/IR/PatternMatch.cpp

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