[PATCH] D137317: [X86][CET] Add Diags for targets pre to i686

[Craig Topper via Phabricator via cfe-commits]

craig.topper added a comment.

In D137317#3905643 <https://reviews.llvm.org/D137317#3905643>, @nickdesaulniers wrote:

> Seems fine, though looking at `llvm::X86::CPUKind`, why do you choose `llvm::X86::CK_PentiumPro` as the lower bounds? Surely `llvm::X86::CK_Pentium2` doesn't support CET?
>
> Does the backend already have an equivalent CPU target check that could be reused by clang?

My understanding was that the CET encodings reuse some encodings that have been equivalent to multibyte NOPs since PentiumPro. I think the intent was that a CET mitigated binary would still run on a CPU that didn't support CET.


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https://reviews.llvm.org/D137317