[PATCH] D158983: [InstCombine] Fold two select patterns into or-and

[Nikita Popov via Phabricator via llvm-commits]

nikic added a comment.

This looks reasonable to me, can you pleas precommit the tests?



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Comment at: llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp:3093
+  // select (c & ~b), a, b -> select b, true, (select c, a, false)
+  if (match(CondVal, m_c_And(m_Value(C), m_Not(m_Specific(FalseVal)))) &&
+      CondVal->hasOneUse()) {
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goldstein.w.n wrote:
> Instead of matching `m_Not` imo should match `m_Specific` and then check `isFreeToInvert` and generate `CreateNot` if that is the case.
I don't get what you're suggesting here. isFreeToInvert doesn't tell you how inverted values are related, which is important here. (We need ~b and b, just being invertible is not enough.)


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https://reviews.llvm.org/D158983