[PATCH] SCEVExpander incorrectly marks increment operations as no-wrap

Sanjoy Das sanjoy at playingwithpointers.com
Wed Feb 25 23:58:15 PST 2015


> Do you think LFTR is a canonicalization? Have you run across SCEV logic that depends on an exit test that checks equality?

No.  As far as I can tell, there does not seem to be any such
restriction within SCEV.

> From what I can remember, LFTR mainly exists so that LSR can create a downward-counting IV. In fact, if that’s the only purpose, LFTR should really be moved to LSR.

That is quite possible.  I've not studied it's effects in depth; it
just sprang out as something that won't work directly on the kind of
IR we generate, so I was wonder how important it was.

-- Sanjoy




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