David Jones via llvm-dev
2019-Feb-13 21:17 UTC
[llvm-dev] Intrinsics for RISCV CSR instructions
I notice that no intrinsics have been defined for the CSRRW/CSRRS/CSRRC instructions. It would be convenient to have intrinsics for these to allow CSR manipulation directly from IR code. Interestingly, this seems to be true for PowerPC (no intrinsics for mfdcr/mtdcr) and X86 (no in/out) as well. Are there plans to define standard RISCV intrinsics for this? -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20190213/d8f473a9/attachment.html>
Alex Bradbury via llvm-dev
2019-Feb-13 21:45 UTC
[llvm-dev] Intrinsics for RISCV CSR instructions
On Wed, 13 Feb 2019, 21:17 David Jones via llvm-dev <llvm-dev at lists.llvm.org wrote:> I notice that no intrinsics have been defined for the CSRRW/CSRRS/CSRRC > instructions. > > It would be convenient to have intrinsics for these to allow CSR > manipulation directly from IR code. > > Interestingly, this seems to be true for PowerPC (no intrinsics for > mfdcr/mtdcr) and X86 (no in/out) as well. > > Are there plans to define standard RISCV intrinsics for this? >Its not something I'd considered but I'd be happy to review a proposal or patches if there's precedent in LLVM with other backends l a good use case justification. Why would intrinsics be preferred to just using inline asm? Best, Alex -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20190213/558e60aa/attachment.html>
David Jones via llvm-dev
2019-Feb-13 21:50 UTC
[llvm-dev] Intrinsics for RISCV CSR instructions
I would like to generate LLVM IR from my custom compiler that will lower to a CSR access instruction. Can I emit arbitrary inline asm from LLVM IR without using clang? On Wed, Feb 13, 2019 at 4:45 PM Alex Bradbury <asb at lowrisc.org> wrote:> > > On Wed, 13 Feb 2019, 21:17 David Jones via llvm-dev < > llvm-dev at lists.llvm.org wrote: > >> I notice that no intrinsics have been defined for the CSRRW/CSRRS/CSRRC >> instructions. >> >> It would be convenient to have intrinsics for these to allow CSR >> manipulation directly from IR code. >> >> Interestingly, this seems to be true for PowerPC (no intrinsics for >> mfdcr/mtdcr) and X86 (no in/out) as well. >> >> Are there plans to define standard RISCV intrinsics for this? >> > > Its not something I'd considered but I'd be happy to review a proposal or > patches if there's precedent in LLVM with other backends l a good use case > justification. Why would intrinsics be preferred to just using inline asm? > > Best, > > Alex >-------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20190213/d72e5c0f/attachment.html>