[PATCH] D100085: [X86] Support -march=rocketlake

Thu Apr 8 19:05:32 PDT 2021

FreddyYe added inline comments.

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Comment at: llvm/lib/Target/X86/X86.td:767
+  // Rocketlake
+  list<SubtargetFeature> RKLAdditionalFeatures = [FeatureAES,
+                                                  FeatureXSAVEC,
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craig.topper wrote:
> FreddyYe wrote:
> > craig.topper wrote:
> > > Is this list this long because SKL includes SGX but RKL doesn't?
> > Yes. And I don't know any simple ways to exclude SGX here, any suggestions?
> Nothing pretty. Guess it depends on if SGX is going to not appear in more future CPUs or if this is a one off case. If it's going to continue then we could remove it from the inheritance and just give it to SKL, ICL, CNL, etc. individually.
> 
> Or we could just not default SGX on for any CPU. It's probably not all that useful in the backend anyway. Clang will put it in the target-feature attribute anyway. Having it in the backend feature lists doesn't really do anything since I don't think we have any IR intrinsics for SGX.
Agree. Like we did in https://reviews.llvm.org/D88006. SGX is also not useful in the backend.

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D100085/new/

https://reviews.llvm.org/D100085