OpenBLAS: Build for riscv64

[eschnett]

No description provided.

[giordano]

[22:23:05] In file included from ../common.h:444,
[22:23:05]                  from generic/trsm_utcopy_8.c:40:
[22:23:05] ../common_riscv64.h:95:11: fatal error: riscv_vector.h: No such file or directory
[22:23:05]    95 | # include <riscv_vector.h>
[22:23:05]       |           ^~~~~~~~~~~~~~~~
[22:23:05] compilation terminated.

It's the same error I've got trying to compile openblas on a RISC-V board with gcc 14

[giordano]

In any case the header file was introduced in gcc 13: gcc-mirror/gcc@7d935cd. I believe we should change https://github.com/JuliaPackaging/BinaryBuilderBase.jl/blob/a548ba29890d3182961d6e477578beea8ffc3e27/src/Rootfs.jl#L478 to allow gcc 13+ only, we need a capable compiler, not an incomplete one.

[eschnett]

It doesn't work with GCC 13 either.

I think the missing header file is part of an extension. We don't target this extension in our default ABI.

[giordano]

I think the missing header file is part of an extension.

It doesn't matter in the dynamic arch build, openblas build system sets compiler flags for the various extensions and then picks up the right kernels at runtime. This is what we do on all other architectures.

[giordano]

It doesn't work with GCC 13 either.

If I'm reading

Yggdrasil/O/OpenBLAS/common.jl

Lines 187 to 188 in 55f29af

	# GCC 12 doesn't support RISC-V vector instructions
	# GCC 13 does not know the type `vfloat32m4x2_t`

correctly the error message is different, isn't it?

[eschnett]

Yes, it's different. The missing header file is there, it's now about a type mismatch. That could be a problem in GCC or in OpenBLAS.

[eschnett]

I'm trying to build protoc at the moment. The build fails with GCC 12 and succeeds with GCC 13. In other words, your original point stands – GCC 13 is better than GCC 12 for riscv64.

[eschnett]

I think we want GCC 14: https://gcc.gnu.org/gcc-14/changes.html : "Support for the vector intrinsics as specified in version 1.0 of the RISC-V vector intrinsic specification."