[PATCH] D104075: [ScalarEvolution] Merge howManyGreaterThans with howManyLessThans.

[Philip Reames via Phabricator via llvm-commits]

reames added inline comments.


================
Comment at: llvm/lib/Analysis/ScalarEvolution.cpp:11401
+    RHS = getNotSCEV(RHS);
+  }
+
----------------
For sanity sake, please actually set Pred here so that if we use it below, we get what we expect.


================
Comment at: llvm/lib/Analysis/ScalarEvolution.cpp:11530
+  // isLoopEntryGuardedByCond isn't very powerful, so we want to look for
+  // more likely patterns.
   const SCEV *BECount;
----------------
I'd prefer to make it more powerful if possible.

A couple ideas, not sure if these work out or not:
* Use SimplifyICmpOperands to canonicalize operands to isBasicBlockEntryGuardedByCond.
* Teach isLoopEntryGuardedByCond to undo your not(lhs/rhs) transform.  


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D104075/new/

https://reviews.llvm.org/D104075