[PATCH] D28625: [InstCombine] try to shrink bitwise logic with phi operand
Eli Friedman via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Thu Jan 19 12:22:34 PST 2017
efriedma added a comment.
Err, sorry, it looks like my comment wasn't really clear about what I was thinking about...
The optimization sort of has two weaknesses in its current state: one the optimization doesn't work if the initial value isn't a constant. Two, it only works if there's a single logical operation per loop iteration. The first could probably be fixed using known bits; I'm more worried about the second one... it's probably not something we would deal with in instcombine. Maybe that's not important.
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