[PATCH] D62158: [InstCombine] canonicalize minnum/maxnum with 'nnan' to fcmp+select

[Matt Arsenault via Phabricator via llvm-commits]

arsenm added a comment.

I'm not sure I see the ValueTracking advantage here. Can you add a test where this matters? I wouldn't expect matchSelectPattern to give any advantage here.

Also last I knew, the use of matchSelectPattern in SelectionDAGBuilder was somewhat buggy. It leaves behind a dead use, so in the initial combine, it breaks hasOneUse checks and prevents necessary early matching. There was also a second problem that I don't remember the details of


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  https://reviews.llvm.org/D62158/new/

https://reviews.llvm.org/D62158