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[X86] Add feature for Fast Short REP MOV (FSRM) for Icelake or newer.
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Authored by yamauchi on Aug 14 2020, 12:38 PM.

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yamauchi created this revision.Aug 14 2020, 12:38 PM
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yamauchi requested review of this revision.Aug 14 2020, 12:38 PM

Is there another patch coming to call hasFSRM()?

Is there another patch coming to call hasFSRM()?

Yes, but not immediately. I'm hoping to get it (for memcpy lowering) ready in the coming weeks.

looks good to me. Wait to see if Craig has any more comments.

This revision is now accepted and ready to land.Aug 19 2020, 10:03 AM
RKSimon added inline comments.
llvm/lib/Target/X86/X86.td
723

Why has this been added to Features and not Tuning?

yamauchi added inline comments.Aug 19 2020, 12:08 PM
llvm/lib/Target/X86/X86.td
723

Following FeatureERMSB which is in HSWAdditionalFeatures.

craig.topper added inline comments.Aug 19 2020, 12:17 PM
llvm/lib/Target/X86/X86.td
723

Both this and ERMSB have CPUID bits so its not microarchitectural.

ERMSB should probably be on IVB where it was introduced but nobody profiled it when the feature was added to llvm.

yamauchi added inline comments.Aug 19 2020, 12:25 PM
llvm/lib/Target/X86/X86.td
723

So it's good to be here in Features?

RKSimon added inline comments.Aug 19 2020, 12:45 PM
llvm/lib/Target/X86/X86.td
723

Yes Features is fine - sorry for the confusion.

yamauchi added inline comments.Aug 19 2020, 1:18 PM
llvm/lib/Target/X86/X86.td
723

Okay. Will commit this.