Open jyknight opened 3 weeks ago
@llvm/issue-subscribers-backend-x86
Author: James Y Knight (jyknight)
The current state of things seems to be that the -mno-3dnow
switch is still accepted by the Clang driver, but using it causes these messages:
'-3dnow' is not a recognized feature for this target (ignoring feature)
'-3dnowa' is not a recognized feature for this target (ignoring feature)
@frobtech #99352 should address this
This issue is about removing IR and SelectionDAG/Codegen support. Assembler support should remain.
Previous discussion on discourse Proposal to remove MMX support
The idea is, at the LLVM level, to keep only minimal support for the inlineasm "y" constraints, and remove as much of the rest as possible.
Overall plan:
x86_mmx
type from IR. Can be done by using (at the IR level only) a standard vector type,<1 x i64>
, instead. Notably, Clang already uses<1 x i64>
for everything except where required to interface with mmx intrinsics and inline-asm. The conversion for those interfaces can be pushed down into SelectionDAG instead. (PR #98505) (PR #100646)@efriedma-quic @phoebewang @topperc @RKSimon