[PATCH] D113779: [Clang] Add mfp16, mfp16fml and mdotprod flags for ARM target features.
David Spickett via Phabricator via cfe-commits
cfe-commits at lists.llvm.org
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
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https://reviews.llvm.org/D113779/new/
https://reviews.llvm.org/D113779
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