Hi!
(This is orthogonal to yesterday's
"GCC 15: nvptx '-mptx=3.1' multilib variants are deprecated".)
We'd like to raise nvptx code generation from PTX ISA 6.0, sm_30 "Kepler"
to default PTX ISA 7.3, sm_52 "Maxwell", therefore CUDA 11.3 (2021-04).
This is, primarily, so that we're able to use 'alloca' and related stack
manipulation instructions, and improve upon the current:
sorry ("target cannot support alloca");
I see, for example:
- Ubuntu 22.04 "jammy" LTS has 11.5.1-1ubuntu1 packaged
- Debian 12 "stable" ("bookworm", 2023-06) has 11.8.89~11.8.0-5~deb12u1
packaged
..., and sm_52 "Maxwell" has been supported as of CUDA 6.5 (2014-08), and
thus supported by most Nvidia GPUs of the last decade, approximately.
The question is, whether we continue to build by default also the current
sm_30 "Kepler" multilib variants (to be available for use via
building/linking with '-march=sm_30'), or if that's truly obsolete by
now, and need no longer be available by default? (It has been deprecated
for a long time, and sm_3x "Kepler architecture support is removed from
CUDA 12.0", 2022-12.) There's always the 'configure'-time
'--with-arch=sm_30' if you (additionally to sm_52) still need your target
libraries built for sm_30 multilib variants; I would argue that's
sufficient?
Grüße
Thomas
