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

[Eli Friedman via Phabricator via llvm-commits]

efriedma added inline comments.


================
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;
----------------
reames wrote:
> 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.  
There's actually another layer of complexity here on the main branch: if LHS/RHS are pointers, we have ptrtoint expressions floating around here, which isLoopEntryGuardedByCond also doesn't handle well.

After D105510 is merged, I can try messing with isLoopEntryGuardedByCond etc.


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

https://reviews.llvm.org/D104075