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[X86] Add FeatureSlowBTMem to Haswell, Broadwell, Skylake, Cannonlake, and Knights Landing CPUs.
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Authored by craig.topper on Oct 13 2017, 9:23 AM.

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Reviewers

RKSimon
zvi
gadi.haber

Commits

rGa1f9c9dd8be5: [X86] Add FeatureSlowBTMem to Haswell, Broadwell, Skylake, Cannonlake, and…
rL315859: [X86] Add FeatureSlowBTMem to Haswell, Broadwell, Skylake, Cannonlake, and…

Summary

I see nothing in Agner Fog's tables to indicate that this improved between Ivy Bridge and Haswell. It's also set for all Atom CPUs so I assume KNL should have it too.

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Repository: rL LLVM

Event Timeline

craig.topper created this revision.Oct 13 2017, 9:23 AM

craig.topper added reviewers: RKSimon, zvi.Oct 13 2017, 9:23 AM

craig.topper added a subscriber: llvm-commits.

RKSimon added a reviewer: gadi.haber.Oct 13 2017, 10:29 AM

Yes. The X86 Bit Test is known to run slowly on all X86 CPUs.

gadi.haber accepted this revision.Oct 15 2017, 7:23 AM

This revision is now accepted and ready to land.Oct 15 2017, 7:23 AM

Closed by commit rL315859: [X86] Add FeatureSlowBTMem to Haswell, Broadwell, Skylake, Cannonlake, and… (authored by ctopper). · Explain WhyOct 15 2017, 9:41 AM

This revision was automatically updated to reflect the committed changes.

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llvm/

trunk/

lib/

Target/

X86/

X86.td

19 lines

Diff 119084

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llvm/trunk/lib/Target/X86/X86.td