<html> <head> <base href="https://bugs.freedesktop.org/"> </head> <body> <div> <a class="bz_bug_link bz_status_ASSIGNED " title="ASSIGNED - [ANV] The Witcher 3 shadows flickering" href="https://bugs.freedesktop.org/show_bug.cgi?id=109404#c25">Comment # 25</a> on <a class="bz_bug_link bz_status_ASSIGNED " title="ASSIGNED - [ANV] The Witcher 3 shadows flickering" href="https://bugs.freedesktop.org/show_bug.cgi?id=109404">bug 109404</a> from <a class="email" href="mailto:idr@freedesktop.org" title="Ian Romanick <idr@freedesktop.org>"> Ian Romanick</a> <pre>Fixed by : commit 2dff9a66b629834bffad47e7a9025e0f1de5ffc3 Author: Matt Turner <<a href="mailto:mattst88@gmail.com">mattst88@gmail.com</a>> Date: Mon Feb 11 16:02:15 2019 -0800 intel/compiler: Avoid propagating inequality cmods if types are different v2: Fix silly bug in logic. s/||/&&/ All but one of the affected shaders is in an Unreal4 demo. The other is in Tomb Raider. All of the cases that Ian investigated appear to be sequences like the following if (int(uint(some_float)) < 0) /* other relations too */ ... At least in Tomb Raider, it's not obvious that this sequence came from the original shader. In some of the Unreal demos, the shader contains code like if (int(uint(textureLod(...))) > 0) ... which explicitly generates the offending sequence. All Gen6+ platforms had similar results (Skylake shown): total instructions in shared programs: 15437170 -> 15437187 (<.01%) instructions in affected programs: 4492 -> 4509 (0.38%) helped: 0 HURT: 17 HURT stats (abs) min: 1 max: 1 x̄: 1.00 x̃: 1 HURT stats (rel) min: 0.05% max: 0.73% x̄: 0.66% x̃: 0.73% 95% mean confidence interval for instructions value: 1.00 1.00 95% mean confidence interval for instructions %-change: 0.57% 0.75% Instructions are HURT. total cycles in shared programs: 383007996 -> 383007992 (<.01%) cycles in affected programs: 20542 -> 20538 (-0.02%) helped: 6 HURT: 7 helped stats (abs) min: 2 max: 6 x̄: 5.33 x̃: 6 helped stats (rel) min: 0.11% max: 0.36% x̄: 0.32% x̃: 0.36% HURT stats (abs) min: 4 max: 4 x̄: 4.00 x̃: 4 HURT stats (rel) min: 0.27% max: 0.27% x̄: 0.27% x̃: 0.27% 95% mean confidence interval for cycles value: -3.30 2.69 95% mean confidence interval for cycles %-change: -0.19% 0.19% Inconclusive result (value mean confidence interval includes 0). No changes on Iron Lake or GM45. Bugzilla: <a class="bz_bug_link bz_status_ASSIGNED " title="ASSIGNED - [ANV] The Witcher 3 shadows flickering" href="show_bug.cgi?id=109404">https://bugs.freedesktop.org/show_bug.cgi?id=109404</a> Reviewed-by: Ian Romanick <<a href="mailto:ian.d.romanick@intel.com">ian.d.romanick@intel.com</a>> Reviewed-by: Jason Ekstrand <<a href="mailto:jason@jlekstrand.net">jason@jlekstrand.net</a>> Tested-by: <a href="mailto:nagrigoriadis@gmail.com">nagrigoriadis@gmail.com</a> Tested-by: Danylo Piliaiev <<a href="mailto:danylo.piliaiev@gmail.com">danylo.piliaiev@gmail.com</a>></pre> </div> <hr> You are receiving this mail because: <ul> <li>You are the QA Contact for the bug.</li> </ul> </body> </html>