[llvm-commits] LLVM patch to support ARM fused multiply add/subtract instructions

[James Molloy]

Hi Ana,

For what it's worth, I've reviewed this and it looks good to me.

Cheers,

James

-----Original Message-----
From: llvm-commits-bounces at cs.uiuc.edu
[mailto:llvm-commits-bounces at cs.uiuc.edu] On Behalf Of Ana Pazos
Sent: 25 January 2012 00:19
To: 'Anton Korobeynikov'
Cc: llvm-commits at cs.uiuc.edu
Subject: Re: [llvm-commits] LLVM patch to support ARM fused multiply
add/subtract instructions

Anton,

Here is an updated patch for the ARM fused multiply add/sub feature with the
relevant suggestions incorporated.

In this update:
- I assumed neon2 does not imply vfpv4, but neon and vfpv4 imply neon2.
- I kept setting .fpu=neon-vfpv4 code attribute because that is what the
assembler understands.

The additional changes mentioned in the email discussions I think belong to
a separate patch:
- Associate VMLA/VMLS with LessPreciseFPMAD flag, and maybe with fast-math
flag.
- VFPv3/VFPv4/NEON/NEON2 associations with FeatureFP16/FeatureD16.
- Support to set -mfpu=neon2 in clang. Do you want this??
  

Thanks,
Ana.

-----Original Message-----
From: llvm-commits-bounces at cs.uiuc.edu
[mailto:llvm-commits-bounces at cs.uiuc.edu] On Behalf Of Anton Korobeynikov
Sent: Tuesday, January 24, 2012 12:34 PM
To: James Molloy
Cc: llvm-commits at cs.uiuc.edu
Subject: Re: [llvm-commits] [llvm] r148658 - in /llvm/trunk:
lib/Target/ARM/ARM.td lib/Target/ARM/ARMAsmPrinter.cpp
lib/Target/ARM/ARMInstrInfo.td lib/Target/ARM/ARMInstrNEON.td
lib/Target/ARM/ARMInstrVFP.td lib/Target/ARM/ARMSchedule.td
lib/Target/ARM/ARMSub

Hi James,

> >From my discussions with colleagues we come to a different conclusion -
that it is indeed possible to have the NEONv2 vector integer unit without
the floating point unit of VFPv4.
> We don't think it's possible to have VFPv4 with NEONv1 however.
Well... this conflicts with that doc I mentioned. Where is the truth? :)

-- 
With best regards, Anton Korobeynikov
Faculty of Mathematics and Mechanics, Saint Petersburg State University
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