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

Thu Nov 3 09:51:14 PDT 2022

nickdesaulniers added a comment.

In D137317#3905654 <https://reviews.llvm.org/D137317#3905654>, @craig.topper wrote:

> 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.

Makes sense; consider adding that additional information as context to the commit message @pengfei .

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D137317/new/

https://reviews.llvm.org/D137317