[PATCH] D43759: [SCEV] Smarter logic in computeConstantDifference

[Max Kazantsev via Phabricator via llvm-commits]

mkazantsev added inline comments.


================
Comment at: lib/Analysis/ScalarEvolution.cpp:9396
+  if (auto *Difference = dyn_cast<SCEVConstant>(
+          getMinusSCEV(More, Less, SCEV::FlagAnyWrap, MaxArithDepth - 1)))
+    return Difference->getAPInt();
----------------
sanjoy wrote:
> I'd much rather not put all of this (albeit non-recursive) work here when it is possible to easily extend the existing code to handle your pattern.
Do we really want to add every easy pattern we find here in future just because it is easy? It looks counter-general. And we don't know how many other relatively simple cases we do not handle.


https://reviews.llvm.org/D43759