-fmath-errno breaks compilation on RX 6700XT (Fedora 40)

[pahaze]

After one of the recent commits, Makefile is edited to have -fmath-errno in it as a CFLAG and CXXFLAG. It does not allow compilation giving undefined errors for logf and expf.

lld: error: undefined hidden symbol: logf
>>> referenced by /tmp/tsembd-gfx1030-34ece1.o:(timestep_embedding_f32(float const*, float*, int, int, int))
>>> referenced by /tmp/tsembd-gfx1030-34ece1.o:(timestep_embedding_f32(float const*, float*, int, int, int))

lld: error: undefined hidden symbol: expf
>>> referenced by /tmp/tsembd-gfx1030-34ece1.o:(timestep_embedding_f32(float const*, float*, int, int, int))
>>> referenced by /tmp/tsembd-gfx1030-34ece1.o:(timestep_embedding_f32(float const*, float*, int, int, int))
clang: error: amdgcn-link command failed with exit code 1 (use -v to see invocation)
make: *** [Makefile:274: ggml/src/ggml-cuda/tsembd.o] Error 1

Removing -fmath-errno allowed the build to work as normal.

[SpoiledCoding]

Thank you-- I ran into this same error and a couple hours of google didn't help.

So I spent a couple more hours to set up ssh on my machine and committed the change to remove the flags. :)

PR here!

[SpoiledCoding]

Closed the PR, comment from YellowRoseCx explained another workaround and the root cause.

[YellowRoseCx]

Here's the official response from AMD:

Hi @YellowRoseCx, I've spoken to the internal team about this. ROCm does not support the -fmath-errno flag on the GPU, so passing this flag to clang is causing your issues. Previously, we were pulling in math functions which did not implement errno to begin with, so this was failing silently. We're looking at finding a way to allow passing -fmath-errno to clang without breaking things so that builds like yours can function as they used to. As a workaround for now, you can pass -Xarch_host -fmath-errno to clang instead of -fmath-errno, which will enable this flag on the host only.

ROCm/ROCm#3573 (comment)

[pahaze]

Nice! Glad to see an official response from AMD, as well as something more official to use than just simply removing the flag.