[PATCH] D36309: [LoopUnroll] Enable option to peel remainder loop

Sam Parker via Phabricator via llvm-commits llvm-commits at lists.llvm.org
Mon Aug 7 08:39:41 PDT 2017

samparker added inline comments.

Comment at: lib/Transforms/Utils/LoopUnrollRuntime.cpp:894
+  if (remainderLoop && PeelRemainder)
+    peelLoop(remainderLoop, Count - 1, LI, SE, DT, AC, PreserveLCSSA);
efriedma wrote:
> I think I would write this using UnrollLoop: full unrolling will result in a slightly simpler CFG because the backedge goes away.  (Granted, later optimizations will probably clean it up either way.)
That's not possible here though. As we only know the maximum trip count, we'll need to maintain comparisons for each iteration and convert the backedges to early exits.


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