[PATCH] D28853: [SelectionDAG] Improve knownbits handling of UMIN/UMAX (PR31293)
Matt Arsenault via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Thu Jan 19 14:13:24 PST 2017
arsenm accepted this revision.
arsenm added inline comments.
This revision is now accepted and ready to land.
Comment at: lib/CodeGen/SelectionDAG/SelectionDAG.cpp:2712-2715
+ // UMAX - we know that the result will have the maximum of the
+ // known one leading bits of the inputs.
+ unsigned LeadOne = KnownOne.countLeadingOnes();
+ LeadOne = std::max(LeadOne, KnownOne2.countLeadingOnes());
Should it also be the minimum of the known leading 0s?
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