[RISCV] Hard float ABI and testing

Hi all,

as part of our research activities, we, the Barcelona Supercomputing
Center [1], are actively looking into RISC-V for HPC. So we are
comitted to make sure the RISC-V LLVM ecosystem thrives in that field
of computing, including (but not limiting to) 64-bit and vector
support.

Linux is pervasive in HPC and we found that the current RISC-V in LLVM
does not support the hard float ABI used by the main distributions
(lp64d) yet.

Our question is about the status of this support. Is it already in the
pipeline and waiting to be upstreamed? Or it hasn't been started yet
by anyone. In the last case, we are interested in contributing an
implementation.

Also, we're planning to set up testing for the RISC-V on Linux (we're
considering LLVM test-suite as a starting point). We wonder if there
are other groups that have been looking into this that could share
their experiences.

Any other suggestions and comments are welcome, of course :slight_smile:

Kind regards,
Roger

[1] www.bsc.es

I’m in the process of ramping up to be an LLVM person at SiFive. We don’t have FP hardware on our current 32 bit CPUs so the soft float ABI is fine there at the moment. Our 64 bit “Freedom Unleashed” cores have an FPU so we’d love to have hard float ABI support in LLVM, but it’s not at the top of our priorities to do it ourselves. We’d be very happy if you implemented it.