Re: [FFmpeg-devel] [PATCH] ff_h[yc]scale_fast_mmext always clobbers %rbx

2015-05-13 Thread Michael Niedermayer
On Tue, May 12, 2015 at 06:12:01PM -0700, Nick Lewycky wrote: > On 11 May 2015 at 16:18, Michael Niedermayer wrote: > > > On Mon, May 11, 2015 at 03:55:40PM -0700, Nick Lewycky wrote: > > > On 8 May 2015 at 14:28, Michael Niedermayer wrote: > > > > > > > On Fri, May 08, 2015 at 12:43:20PM -0700,

Re: [FFmpeg-devel] [PATCH] ff_h[yc]scale_fast_mmext always clobbers %rbx

2015-05-12 Thread Nick Lewycky
On 11 May 2015 at 16:18, Michael Niedermayer wrote: > On Mon, May 11, 2015 at 03:55:40PM -0700, Nick Lewycky wrote: > > On 8 May 2015 at 14:28, Michael Niedermayer wrote: > > > > > On Fri, May 08, 2015 at 12:43:20PM -0700, Nick Lewycky wrote: > > > > On 8 May 2015 at 12:06, Michael Niedermayer

Re: [FFmpeg-devel] [PATCH] ff_h[yc]scale_fast_mmext always clobbers %rbx

2015-05-11 Thread Michael Niedermayer
On Mon, May 11, 2015 at 03:55:40PM -0700, Nick Lewycky wrote: > On 8 May 2015 at 14:28, Michael Niedermayer wrote: > > > On Fri, May 08, 2015 at 12:43:20PM -0700, Nick Lewycky wrote: > > > On 8 May 2015 at 12:06, Michael Niedermayer wrote: > > > > > > > On Fri, May 08, 2015 at 10:50:49AM -0700,

Re: [FFmpeg-devel] [PATCH] ff_h[yc]scale_fast_mmext always clobbers %rbx

2015-05-11 Thread Nick Lewycky
On 8 May 2015 at 14:28, Michael Niedermayer wrote: > On Fri, May 08, 2015 at 12:43:20PM -0700, Nick Lewycky wrote: > > On 8 May 2015 at 12:06, Michael Niedermayer wrote: > > > > > On Fri, May 08, 2015 at 10:50:49AM -0700, Nick Lewycky wrote: > > > > On 6 May 2015 at 18:03, Michael Niedermayer >

Re: [FFmpeg-devel] [PATCH] ff_h[yc]scale_fast_mmext always clobbers %rbx

2015-05-08 Thread Michael Niedermayer
On Fri, May 08, 2015 at 12:43:20PM -0700, Nick Lewycky wrote: > On 8 May 2015 at 12:06, Michael Niedermayer wrote: > > > On Fri, May 08, 2015 at 10:50:49AM -0700, Nick Lewycky wrote: > > > On 6 May 2015 at 18:03, Michael Niedermayer wrote: > > > > > > > On Wed, May 06, 2015 at 04:08:09PM -0700,

Re: [FFmpeg-devel] [PATCH] ff_h[yc]scale_fast_mmext always clobbers %rbx

2015-05-08 Thread Nick Lewycky
On 8 May 2015 at 12:06, Michael Niedermayer wrote: > On Fri, May 08, 2015 at 10:50:49AM -0700, Nick Lewycky wrote: > > On 6 May 2015 at 18:03, Michael Niedermayer wrote: > > > > > On Wed, May 06, 2015 at 04:08:09PM -0700, Nick Lewycky wrote: > > > > On 6 May 2015 at 15:06, Michael Niedermayer >

Re: [FFmpeg-devel] [PATCH] ff_h[yc]scale_fast_mmext always clobbers %rbx

2015-05-08 Thread Michael Niedermayer
On Fri, May 08, 2015 at 10:50:49AM -0700, Nick Lewycky wrote: > On 6 May 2015 at 18:03, Michael Niedermayer wrote: > > > On Wed, May 06, 2015 at 04:08:09PM -0700, Nick Lewycky wrote: > > > On 6 May 2015 at 15:06, Michael Niedermayer wrote: > > > > > > > Hi > > > > > > > > On Wed, May 06, 2015 at

Re: [FFmpeg-devel] [PATCH] ff_h[yc]scale_fast_mmext always clobbers %rbx

2015-05-08 Thread Nick Lewycky
On 6 May 2015 at 18:03, Michael Niedermayer wrote: > On Wed, May 06, 2015 at 04:08:09PM -0700, Nick Lewycky wrote: > > On 6 May 2015 at 15:06, Michael Niedermayer wrote: > > > > > Hi > > > > > > On Wed, May 06, 2015 at 11:52:59AM -0700, Nick Lewycky wrote: > > > > Newer versions of clang will al

Re: [FFmpeg-devel] [PATCH] ff_h[yc]scale_fast_mmext always clobbers %rbx

2015-05-06 Thread Michael Niedermayer
On Wed, May 06, 2015 at 04:08:09PM -0700, Nick Lewycky wrote: > On 6 May 2015 at 15:06, Michael Niedermayer wrote: > > > Hi > > > > On Wed, May 06, 2015 at 11:52:59AM -0700, Nick Lewycky wrote: > > > Newer versions of clang will allocate %rbx as one of the inline asm > > inputs, > > > > Thats gre

Re: [FFmpeg-devel] [PATCH] ff_h[yc]scale_fast_mmext always clobbers %rbx

2015-05-06 Thread Nick Lewycky
On 6 May 2015 at 15:06, Michael Niedermayer wrote: > Hi > > On Wed, May 06, 2015 at 11:52:59AM -0700, Nick Lewycky wrote: > > Newer versions of clang will allocate %rbx as one of the inline asm > inputs, > > Thats great > > > > even in PIC. This occurs when building ffmpeg with clang > -fsanitize

Re: [FFmpeg-devel] [PATCH] ff_h[yc]scale_fast_mmext always clobbers %rbx

2015-05-06 Thread Michael Niedermayer
Hi On Wed, May 06, 2015 at 11:52:59AM -0700, Nick Lewycky wrote: > Newer versions of clang will allocate %rbx as one of the inline asm inputs, Thats great > even in PIC. This occurs when building ffmpeg with clang -fsanitize=address > -O1 -fPIE. Because the asm does clobber %bx whether PIC is o

Re: [FFmpeg-devel] [PATCH] ff_h[yc]scale_fast_mmext always clobbers %rbx

2015-05-06 Thread Nick Lewycky
On 6 May 2015 at 13:08, Carl Eugen Hoyos wrote: > Nick Lewycky google.com> writes: > > > On 6 May 2015 at 11:58, Carl Eugen Hoyos: > > > > > Nick Lewycky google.com> writes: > > > > > > > This occurs when building ffmpeg with clang > > > > -fsanitize=address -O1 -fPIE. > > > > > > What is the u

Re: [FFmpeg-devel] [PATCH] ff_h[yc]scale_fast_mmext always clobbers %rbx

2015-05-06 Thread Carl Eugen Hoyos
Nick Lewycky google.com> writes: > On 6 May 2015 at 11:58, Carl Eugen Hoyos: > > > Nick Lewycky google.com> writes: > > > > > This occurs when building ffmpeg with clang > > > -fsanitize=address -O1 -fPIE. > > > > What is the usecase for -O1? > > It's very important for asan. ASan instruments

Re: [FFmpeg-devel] [PATCH] ff_h[yc]scale_fast_mmext always clobbers %rbx

2015-05-06 Thread Nick Lewycky
On 6 May 2015 at 11:58, Carl Eugen Hoyos wrote: > Nick Lewycky google.com> writes: > > > This occurs when building ffmpeg with clang > > -fsanitize=address -O1 -fPIE. > > What is the usecase for -O1? > It's very important for asan. ASan instruments every memory access (outside inline asm, for n

Re: [FFmpeg-devel] [PATCH] ff_h[yc]scale_fast_mmext always clobbers %rbx

2015-05-06 Thread Carl Eugen Hoyos
Nick Lewycky google.com> writes: > This occurs when building ffmpeg with clang > -fsanitize=address -O1 -fPIE. What is the usecase for -O1? Did you check performance with and without your patch? Carl Eugen ___ ffmpeg-devel mailing list ffmpeg-devel@

[FFmpeg-devel] [PATCH] ff_h[yc]scale_fast_mmext always clobbers %rbx

2015-05-06 Thread Nick Lewycky
Newer versions of clang will allocate %rbx as one of the inline asm inputs, even in PIC. This occurs when building ffmpeg with clang -fsanitize=address -O1 -fPIE. Because the asm does clobber %bx whether PIC is on or off, just include %bx in the clobber list regardless of whether PIC is on or off.