[PATCH] D146054: [RISCV] Add --print-supported-extensions and -march=help support

[Fangrui Song via Phabricator via cfe-commits]

MaskRay added a comment.

`-march=` `-mcpu=` `-mtune=` are from GCC and they traditionally have many opinions on the features.
If GCC is going to have `-march=help`, I think adding `-march=help` to Clang to match is fine.
But I'd really like to avoid aliases for non-compatibility reasons. They just cause confusion and make users undecided about which one is canonical.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D146054/new/

https://reviews.llvm.org/D146054