[PATCH] D105142: RFC: Implementing new mechanism for hard register operands to inline asm as a constraint.

[James Y Knight via Phabricator via cfe-commits]

jyknight added a comment.

This code doesn't handle multiple alternatives in a constraint.

E.g. `"={eax}{ebx}"` or `"={eax}{ebx},m"`.

See the GCC docs for the C-level syntax
https://gcc.gnu.org/onlinedocs/gcc/Multi-Alternative.html#Multi-Alternative
and LLVM IR docs for the IR syntax:
https://llvm.org/docs/LangRef.html#constraint-codes

LLVM doesn't handle alternatives very well in the backend, but Clang at least should parse and properly generate LLVM asm strings for these cases I think.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D105142/new/

https://reviews.llvm.org/D105142