Re: RFC: ARM Cortex-A8 and floating point performance

2010-07-01 Thread Richard Guenther
On Thu, Jul 1, 2010 at 5:30 PM, Richard Earnshaw wrote: > > On Wed, 2010-06-16 at 08:09 -0700, Andrew Pinski wrote: >> >> Sent from my iPhone >> >> On Jun 16, 2010, at 6:04 AM, Richard Guenther >  > wrote: >> >> > On Wed, Jun 16, 2010 at 5:52 PM, Siarhei Siamashka >> > wrote: >> >> Hello, >> >> >

Re: RFC: ARM Cortex-A8 and floating point performance

2010-07-01 Thread Richard Earnshaw
On Wed, 2010-06-16 at 08:09 -0700, Andrew Pinski wrote: > > Sent from my iPhone > > On Jun 16, 2010, at 6:04 AM, Richard Guenther > wrote: > > > On Wed, Jun 16, 2010 at 5:52 PM, Siarhei Siamashka > > wrote: > >> Hello, > >> > >> Currently gcc (at least version 4.5.0) does a very poor job >

Re: RFC: ARM Cortex-A8 and floating point performance

2010-06-17 Thread David Brown
On 16/06/2010 17:09, Andrew Pinski wrote: On i?86 we have -mfpmath={sse,x87}, I suppose you could add -mfpmath=neon for arm (properly conflicting with -mfloat-abi=hard and requiring neon support). Except unlike sse, neon does not fully support IEEE support. So this should only be done with

Re: RFC: ARM Cortex-A8 and floating point performance

2010-06-17 Thread Siarhei Siamashka
On Wednesday 16 June 2010 15:22:32 Ramana Radhakrishnan wrote: > On Wed, 2010-06-16 at 15:52 +, Siarhei Siamashka wrote: > > Currently gcc (at least version 4.5.0) does a very poor job generating > > single precision floating point code for ARM Cortex-A8. > > > > The source of this problem is t

Re: RFC: ARM Cortex-A8 and floating point performance

2010-06-16 Thread Ramana Radhakrishnan
On Wed, 2010-06-16 at 15:52 +, Siarhei Siamashka wrote: > Hello, > > Currently gcc (at least version 4.5.0) does a very poor job generating single > precision floating point code for ARM Cortex-A8. > > The source of this problem is the use of VFP instructions which are run on a > slow nonp

Re: RFC: ARM Cortex-A8 and floating point performance

2010-06-16 Thread Andrew Pinski
Sent from my iPhone On Jun 16, 2010, at 6:04 AM, Richard Guenther > wrote: On Wed, Jun 16, 2010 at 5:52 PM, Siarhei Siamashka wrote: Hello, Currently gcc (at least version 4.5.0) does a very poor job generating single precision floating point code for ARM Cortex-A8. The source of this

Re: RFC: ARM Cortex-A8 and floating point performance

2010-06-16 Thread Richard Guenther
On Wed, Jun 16, 2010 at 5:52 PM, Siarhei Siamashka wrote: > Hello, > > Currently gcc (at least version 4.5.0) does a very poor job generating single > precision floating point code for ARM Cortex-A8. > > The source of this problem is the use of VFP instructions which are run on a > slow nonpipelin

RFC: ARM Cortex-A8 and floating point performance

2010-06-16 Thread Siarhei Siamashka
Hello, Currently gcc (at least version 4.5.0) does a very poor job generating single precision floating point code for ARM Cortex-A8. The source of this problem is the use of VFP instructions which are run on a slow nonpipelined VFP Lite unit in Cortex-A8. Even turning on RunFast mode (flush d