[PATCH] D33862: [x86] avoid flipping sign bits for vector icmp by using known bits

[Simon Pilgrim via Phabricator via llvm-commits]

RKSimon added a comment.

> Are we better off using pcmpgt + min/max/psubus instructions instead of inverting a pcmp?

TBH, I think the min/max/psubus cases are preferable.

> Since we're computing known bits, should we try harder to eliminate other compares like (known negative < known positive)?

There's definitely scope in InstCombine/DAGCombine to use KnownBits to fold more comparisons.


https://reviews.llvm.org/D33862