| Message ID | 3c8116811516c04d11397f392f9a6008@linux.vnet.ibm.com |
|---|---|
| State | Accepted |
| Commit | 3a557c5d88b7b15b5954ba2743febb055549b536 |
| Headers | show |
How do I get someone to look at this patch? > A bug exist with the gcc compilers for Power in versions 6.x and 7.x > (verified with 6.3 and 7.4). It was fixed in version 8.x (verified > with 8.3). I was using a Power 9 ppc64le machine for building and > testing. > This is to address ticket #7124. > > It appears the compiler is generating the wrong code for little endian > machines for the vec_lvsl/vec_perm instruction combos in some cases. > If these instructions are replaced with vec_xl, the problem goes away > for all versions of the compilers. > > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > To unsubscribe, visit link above, or email > ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
> Am 12.08.2019 um 16:21 schrieb ckerchne <ckerchne@linux.vnet.ibm.com>: > > How do I get someone to look at this patch? > >> A bug exist with the gcc compilers for Power in versions 6.x and 7.x >> (verified with 6.3 and 7.4). It was fixed in version 8.x (verified >> with 8.3). I was using a Power 9 ppc64le machine for building and >> testing. >> This is to address ticket #7124. >> It appears the compiler is generating the wrong code for little endian >> machines for the vec_lvsl/vec_perm instruction combos in some cases. >> If these instructions are replaced with vec_xl, the problem goes away >> for all versions of the compilers. As said, this commit message is not ok, please add information on how the issue can actually be reproduced. And please avoid top-posting here. Carl Eugen
Am Fr., 2. Aug. 2019 um 17:24 Uhr schrieb ckerchne <ckerchne@linux.vnet.ibm.com>: > > A bug exist with the gcc compilers for Power in versions 6.x and 7.x > (verified with 6.3 and 7.4). It was fixed in version 8.x (verified with > 8.3). I was using a Power 9 ppc64le machine for building and testing. > This is to address ticket #7124. > > It appears the compiler is generating the wrong code for little endian > machines for the vec_lvsl/vec_perm instruction combos in some cases. If > these instructions are replaced with vec_xl, the problem goes away for > all versions of the compilers I tested with gcc 7 (gcc 6 fails compilation for ppc64le) and was unable to see a speed difference on be, so pushed. For future patches: Please provide patches as made by git format-patch, not diff files. Thank you for the fix, Carl Eugen
Am Fr., 2. Aug. 2019 um 17:24 Uhr schrieb ckerchne <ckerchne@linux.vnet.ibm.com>: > > A bug exist with the gcc compilers for Power in versions 6.x and 7.x > (verified with 6.3 and 7.4). It was fixed in version 8.x (verified with > 8.3). I was using a Power 9 ppc64le machine for building and testing. > This is to address ticket #7124. > > It appears the compiler is generating the wrong code for little endian > machines for the vec_lvsl/vec_perm instruction combos in some cases. If > these instructions are replaced with vec_xl, the problem goes away for > all versions of the compilers. This patch broke compilation on ppc64be with gcc 9.3 (Debian sid): src/libswscale/ppc/yuv2rgb_altivec.c: In function ‘altivec_yuv2_abgr’: src/libswscale/ppc/yuv2rgb_altivec.c:338:18: error: implicit declaration of function ‘vec_xl’; did you mean ‘vec_rl’? [-Werror=implicit-function-declaration] 338 | y0 = vec_xl(0, y1i); Carl Eugen
diff --git a/libswscale/ppc/yuv2rgb_altivec.c b/libswscale/ppc/yuv2rgb_altivec.c index c1e2852adb..536545293d 100644 --- a/libswscale/ppc/yuv2rgb_altivec.c +++ b/libswscale/ppc/yuv2rgb_altivec.c @@ -305,9 +305,6 @@ static int altivec_ ## name(SwsContext *c, const unsigned char **in, \ vector signed short R1, G1, B1; \ vector unsigned char R, G, B; \ \ - const vector unsigned char *y1ivP, *y2ivP, *uivP, *vivP; \ - vector unsigned char align_perm; \ - \ vector signed short lCY = c->CY; \ vector signed short lOY = c->OY; \ vector signed short lCRV = c->CRV; \ @@ -338,26 +335,13 @@ static int altivec_ ## name(SwsContext *c, const unsigned char **in, \ vec_dstst(oute, (0x02000002 | (((w * 3 + 32) / 32) << 16)), 1); \ \ for (j = 0; j < w / 16; j++) { \ - y1ivP = (const vector unsigned char *) y1i; \ - y2ivP = (const vector unsigned char *) y2i; \ - uivP = (const vector unsigned char *) ui; \ - vivP = (const vector unsigned char *) vi; \ - \ - align_perm = vec_lvsl(0, y1i); \ - y0 = (vector unsigned char) \ - vec_perm(y1ivP[0], y1ivP[1], align_perm); \ + y0 = vec_xl(0, y1i); \ \ - align_perm = vec_lvsl(0, y2i); \ - y1 = (vector unsigned char) \ - vec_perm(y2ivP[0], y2ivP[1], align_perm); \ + y1 = vec_xl(0, y2i); \ \ - align_perm = vec_lvsl(0, ui); \ - u = (vector signed char) \ - vec_perm(uivP[0], uivP[1], align_perm); \ + u = (vector signed char) vec_xl(0, ui); \ \ - align_perm = vec_lvsl(0, vi); \ - v = (vector signed char) \ - vec_perm(vivP[0], vivP[1], align_perm); \ + v = (vector signed char) vec_xl(0, vi); \ \ u = (vector signed char) \ vec_sub(u, \