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[X86] Add prefer-128-bit subtarget feature.
ClosedPublic

Authored by craig.topper on Sep 6 2019, 9:35 PM.

Details

Summary

Similar to the previous prefer-256-bit flag. We might want to
enable this by default some CPUs. This just starts the initial
work to implement and prove that it effects TTI's vector width.

Diff Detail

Repository
rL LLVM

Event Timeline

craig.topper created this revision.Sep 6 2019, 9:35 PM
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lebedev.ri added inline comments.
llvm/lib/Target/X86/X86.td
383 ↗(On Diff #219221)

Did you mean SSE?

craig.topper marked an inline comment as done.Sep 7 2019, 12:30 AM
craig.topper added inline comments.
llvm/lib/Target/X86/X86.td
383 ↗(On Diff #219221)

We'll end up using 128-bit VEX encoded instructions which are part of AVX/AVX2

RKSimon accepted this revision.Sep 7 2019, 4:45 AM

LGTM - this could be useful!

This revision is now accepted and ready to land.Sep 7 2019, 4:45 AM
This revision was automatically updated to reflect the committed changes.