[PATCH] D102550: [ValueTracking] Mark GEP operand as nonnull if the result was loaded or stored

[Danila Kutenin via Phabricator via llvm-commits]

danlark added inline comments.


================
Comment at: llvm/lib/Analysis/ValueTracking.cpp:2137
+          V == GEP->getPointerOperand() &&
+          isGEPKnownNonNull(GEP, Depth + 1, Q)) {
+        unsigned GEPUsesExplored = 0;
----------------
lebedev.ri wrote:
> danlark wrote:
> > lebedev.ri wrote:
> > > Doesn't this cause endless recursion back into `isKnownNonNullFromDominatingCondition()`
> > > for the very same value we've started with?
> > > (and we happen to not deadloop just because of depth cutoff)
> > > 
> > isKnownNonZero has Depth cutoff before isKnownNonNullFromDominatingCondition
> > 
> > https://github.com/llvm/llvm-project/blob/e38ccb729b205b076356684e055efb7dfc673963/llvm/lib/Analysis/ValueTracking.cpp#L2304-L2336
> Sure, but before that cutoff triggers, won't we waste time mutually recursing with no progress?
Not to compute the same values we may not go recursively and only look for constants, I believe this is the most popular case


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https://reviews.llvm.org/D102550