Robison, Arch
2014-Dec-10 20:48 UTC
[LLVMdev] Best way for JIT to query whether llvm.fma.* is fast?
For the Julia language JIT, we'd like be able to tell whether the llvm.fma.* intrinsic has hardware support. What's the best way to query LLVM (JIT) for this information? The information would be used in situations where the user wants to use different algorithms depending on whether FMA hardware is present or not. - Arch D. Robison -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20141210/60216d28/attachment.html>
Jingyue Wu
2014-Dec-10 20:55 UTC
[LLVMdev] Best way for JIT to query whether llvm.fma.* is fast?
Does TargetLowering::isFMAFasterThanFMulAndFAdd ( http://llvm.org/docs/doxygen/html/TargetLowering_8h_source.html#l01499) help? Jingyue On Wed, Dec 10, 2014 at 12:48 PM, Robison, Arch <arch.robison at intel.com> wrote:> For the Julia language JIT, we’d like be able to tell whether the > llvm.fma.* intrinsic has hardware support. What’s the best way to query > LLVM (JIT) for this information? > > The information would be used in situations where the user wants to use > different algorithms depending on whether FMA hardware is present or not. > > - Arch D. Robison > > > _______________________________________________ > LLVM Developers mailing list > LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu > http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev > >-------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20141210/b5edd658/attachment.html>
Robison, Arch
2014-Dec-10 21:17 UTC
[LLVMdev] Best way for JIT to query whether llvm.fma.* is fast?
Thanks! That’s probably close enough for practical purposes. I looked at the overrides on various targets, and they all return true if the FMA hardware exists. - Arch From: Jingyue Wu [mailto:jingyue at google.com] Sent: Wednesday, December 10, 2014 2:56 PM To: Robison, Arch Cc: llvmdev at cs.uiuc.edu Subject: Re: [LLVMdev] Best way for JIT to query whether llvm.fma.* is fast? Does TargetLowering::isFMAFasterThanFMulAndFAdd (http://llvm.org/docs/doxygen/html/TargetLowering_8h_source.html#l01499) help? Jingyue On Wed, Dec 10, 2014 at 12:48 PM, Robison, Arch <arch.robison at intel.com<mailto:arch.robison at intel.com>> wrote: For the Julia language JIT, we’d like be able to tell whether the llvm.fma.* intrinsic has hardware support. What’s the best way to query LLVM (JIT) for this information? The information would be used in situations where the user wants to use different algorithms depending on whether FMA hardware is present or not. - Arch D. Robison _______________________________________________ LLVM Developers mailing list LLVMdev at cs.uiuc.edu<mailto:LLVMdev at cs.uiuc.edu> http://llvm.cs.uiuc.edu http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20141210/6a8cba1c/attachment.html>