Page MenuHomePhabricator

[X86] Add support for forming vXi16 PMULH instructions from shifts.

Authored by craig.topper on Sat, May 9, 6:13 PM.



We already form PMULH when the shift is truncated. But we can
also do it from just a shift by extending the result.

Unfortunately, I get regressions if I try to replace the truncate
combine with this as we turn the truncate into a more complicated
sequence first. Then we are unable to combine that sequence with
the extend produced at the end of this combine.

Diff Detail

Event Timeline

craig.topper created this revision.Sat, May 9, 6:13 PM
Herald added a project: Restricted Project. · View Herald TranscriptSat, May 9, 6:13 PM
Herald added a subscriber: hiraditya. · View Herald Transcript
RKSimon accepted this revision.Thu, May 14, 5:02 AM


This revision is now accepted and ready to land.Thu, May 14, 5:02 AM
This revision was automatically updated to reflect the committed changes.