[LLVMdev] LLVM on ARM testing.

Karel Gardas karel.gardas at centrum.cz
Fri Jul 8 01:31:35 PDT 2011

Hi Renato,

On 07/ 5/11 12:20 PM, Renato Golin wrote:
> On 3 July 2011 21:32, Karel Gardas<karel.gardas at centrum.cz>  wrote:
>> please see http://ghcarm.wordpress.com/2011/07/03/llvm-on-arm-testing/
>> Is there anything other I might do for you to get those regressions fixed?
> Hi Karel,
> This is great!
> I can see there's only a handful of errors. All JIT errors seem to be
> the same (MC). All O2 errors, too (MIPS). The select.ll error was
> fixed by Eli last month, so not to worry.

W.r.t select.ll error, I'm not sure it is really fixed. I'll need to 
retest I'm using here few days old HEAD so it'll be quick.

> Do we have a similar thing for x86? Just to make sure the Mips errors
> are not ARM specific.

I'm not sure, I don't test on x86, but my general feeling about LLVM-2.9 
on x86 and ARM, was that x86 was in better shape -- that was a time I 
tested on x86...

> About your configure options, I have some questions:
> - You use "--with-arch=armv6 --with-tune=cortex-a8", shouldn't it be armv7?
> - You're using softfp on Cortex-A8, have you tried with VFPv3/NEON?
> - On GCC 4.4.5 you're using "--with-float=softfp --with-fpu=vfpv3-d16"
> and (correctly) "--with-arch=armv7-a", which mode prevails? Soft or
> hard?
> - You're using Thumb on 4.4.5 and 4.5.2 only, any special reason not
> to use Thumb on previous GCCs?

All the questions above are answered with simple answer: I'm using 
system (i.e. ubuntu) provided GCC (except linaro) and so the params are 
those Ubuntu package maintaners used. On linaro I'm using ARM mode based 
on the experience with 4.4.1 which also uses ARM mode and looks better 
than 4.4.3/4.5.2 which are using thumb by default.

No, I've not tried to use VFPv3/NEON yet.


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