[PATCH] D140851: [Patch 3/4]: Add cases for assume (X & Y != {0|Y})

[Noah Goldstein via Phabricator via llvm-commits]

goldstein.w.n added inline comments.


================
Comment at: llvm/lib/Analysis/ValueTracking.cpp:950
+            KnownBits AKnown = computeKnownBits(A, Depth + 1, QueryNoAC)
+                                   .anyextOrTrunc(BitWidth);
+            if (AKnown.isZero()) {
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nikic wrote:
> goldstein.w.n wrote:
> > nikic wrote:
> > > This should just check whether A is zero, no need to compute known bits.
> > > This should just check whether A is zero, no need to compute known bits.
> > 
> > How can I check if a value is known zero w.o `computeKnownBits`? I see `isKnownNonZero` but not the inverse.
> `match(A, m_Zero())` would be the usual way.
> `match(A, m_Zero())` would be the usual way.

Won't that only match `Constant` types? Could miss a case no?


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  https://reviews.llvm.org/D140851/new/

https://reviews.llvm.org/D140851