[PATCH] D113779: [Clang] Add mfp16, mfp16fml and mdotprod flags for ARM target features.

Mon Nov 15 01:42:39 PST 2021

DavidSpickett added subscribers: manojgupta, DavidSpickett.
DavidSpickett added a comment.

There was a similar proposal for crypto https://reviews.llvm.org/D60472.

Quoting @manojgupta for the pitch for that:

> The motivation for this change is to make "crypto" setting an additive option e.g. like "-mavx" used in many media packages. Some packages in Chrome want to enable crypto conditionally for a few files to allow crypto feature to be used based on runtime cpu detection. They set "-march=armv8+crypto" flag but it gets overridden by the global "-march=armv8a" flag set by the build system in Chrome OS because the target cpu does not support crypto causing compile-time errors.
> Ability to specify "-mcrypto" standalone makes it an additive option and ensures that it it is not lost. i.e. this will help in decoupling "-mcrypto" from "-march" so that they could be set independently. The current additive alternate is '-Xclang -target-feature -Xclang "+crypto" ' which is ugly.

Concerns were raised there.

Seems like we're balancing adding a bunch of (clang only for at least the short term) options versus making the build system(s) cope with having to track what the last `-march` was.

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D113779/new/

https://reviews.llvm.org/D113779