Re: [RFC] Add FMA support to sparc backend

2011-09-22 Thread Michael Meissner
On Wed, Sep 21, 2011 at 05:01:31PM -0400, David Miller wrote: > From: Michael Meissner > Date: Thu, 15 Sep 2011 14:16:45 -0400 > > > On the powerpc, we have an issue with Spec 2006 and calculix when FMAs are > > generated and -ffast-math is used, where line 307 of rubber.f is: > > > > tt=dat

Re: [RFC] Add FMA support to sparc backend

2011-09-21 Thread David Miller
From: Michael Meissner Date: Thu, 15 Sep 2011 14:16:45 -0400 > On the powerpc, we have an issue with Spec 2006 and calculix when FMAs are > generated and -ffast-math is used, where line 307 of rubber.f is: > > tt=datan2(dsqrt(1.d0-cn*cn),cn)/3.d0 > > The FNMSUB instruction generates a -0.

Re: [RFC] Add FMA support to sparc backend

2011-09-16 Thread David Miller
From: Eric Botcazou Date: Fri, 16 Sep 2011 22:53:09 +0200 >> There have never been TFmode float operations implemented in hardware >> ever for sparc, and I doubt we'll see it in the future. >> >> And this applies also to the FMA instructions. > > Do the specs totally disregard quad floats for FM

Re: [RFC] Add FMA support to sparc backend

2011-09-16 Thread Eric Botcazou
> There have never been TFmode float operations implemented in hardware > ever for sparc, and I doubt we'll see it in the future. > > And this applies also to the FMA instructions. Do the specs totally disregard quad floats for FMA or...? > And especially since the presence of the FMA patterns is

Re: [RFC] Add FMA support to sparc backend

2011-09-16 Thread David Miller
From: Eric Botcazou Date: Fri, 16 Sep 2011 22:25:41 +0200 > What's the story with TFmode for FMA? There have never been TFmode float operations implemented in hardware ever for sparc, and I doubt we'll see it in the future. And this applies also to the FMA instructions. And especially since th

Re: [RFC] Add FMA support to sparc backend

2011-09-16 Thread Eric Botcazou
> Second, like rs6000 the sparc negate fused multiply instructions > negate the full result, not the multiply result. So we cannot use > those instructions for the fnmadf4/fnmsdf4/fnmasf4/fnmssf4 patterns. > Since rs6000 provides patterns for such negate operations (presumably > just in case the c

Re: [RFC] Add FMA support to sparc backend

2011-09-15 Thread Michael Meissner
On Wed, Sep 14, 2011 at 04:00:02AM -0400, David Miller wrote: > > Eric, this is a preliminary version of the FMA patch I've been > working on. Just so you can see what I'm doing. > > First, ignore the fact that there are two configure tests for the > presence of support for these instructions.