On 18 December 2013 09:42, Tim Northover <t.p.northover at gmail.com> wrote:> That means one strictly newer than > cortex-a8: cortex-a7 (don't ask), cortex-a9, cortex-a12, cortex-a15 or > krait I believe. >Hi Tim, Cortex A8 and A9 use VFPv3. A7, A12 and A15 use VFPv4. cheers, --renato -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20131218/4d77d09c/attachment.html>
> Cortex A8 and A9 use VFPv3. A7, A12 and A15 use VFPv4.That's what I thought! But we do seem to generate vfma on Cortex-A9. Wonder if that's a bug, or Cortex-A9 is "VFPv3, but chuck in vfma too"? Tim.
On 18 December 2013 12:31, Tim Northover <t.p.northover at gmail.com> wrote:> That's what I thought! But we do seem to generate vfma on Cortex-A9. > Wonder if that's a bug, or Cortex-A9 is "VFPv3, but chuck in vfma > too"? >Hi Tim, I believe that's the NEON VMLA, not the VFP one. There was a discussion in the past about not using NEON and VFP interchangeably due to IEEE assurances (which NEON doesn't have), but the performance gains are too big. I think the conclusion is to only use NEON instead of VFP (when they're semantically similar) when -unsafe-math is on. cheers, --renato -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20131218/0ca54323/attachment.html>