<html> <head> <base href="https://bugs.freedesktop.org/"> </head> <body> <div> <a class="bz_bug_link bz_status_NEW " title="NEW - [IVB] Font rendering problem in OpenGL" href="https://bugs.freedesktop.org/show_bug.cgi?id=109759#c6">Comment # 6</a> on <a class="bz_bug_link bz_status_NEW " title="NEW - [IVB] Font rendering problem in OpenGL" href="https://bugs.freedesktop.org/show_bug.cgi?id=109759">bug 109759</a> from <a class="email" href="mailto:lionel.g.landwerlin@linux.intel.com" title="Lionel Landwerlin <lionel.g.landwerlin@linux.intel.com>"> Lionel Landwerlin</a> <pre>Bisected to : commit 4cd1a0be76883c2b13aae8c97972e8f1404d06f7 Author: Ian Romanick <<a href="mailto:ian.d.romanick@intel.com">ian.d.romanick@intel.com</a>> Date: Tue Jun 19 18:09:05 2018 -0700 i965/vec4: Propagate conditional modifiers from more compares to other compares If there is a CMP.NZ that compares a single component (via a .zzzz swizzle, for example) with 0, it can propagate its conditional modifier back to a previous CMP that writes only that component. The specific case that I saw was: cmp.l.f0(8) g42<1>.xF g61<4>.xF (abs)g18<4>.zF ... cmp.nz.f0(8) null<1>D g42<4>.xD 0D In this case we can just delete the second CMP. No changes on Broadwell or Skylake because they do not use the vec4 backend. Also no changes on GM45 or Iron Lake. Sandy Bridge, Ivy Bridge, and Haswell had similar results. (Sandy Bridge shown) total instructions in shared programs: 10856676 -> 10852569 (-0.04%) instructions in affected programs: 228322 -> 224215 (-1.80%) helped: 1331 HURT: 0 helped stats (abs) min: 1 max: 7 x̄: 3.09 x̃: 4 helped stats (rel) min: 0.11% max: 6.67% x̄: 1.88% x̃: 1.83% 95% mean confidence interval for instructions value: -3.19 -2.99 95% mean confidence interval for instructions %-change: -1.93% -1.83% Instructions are helped. total cycles in shared programs: 154788865 -> 154732047 (-0.04%) cycles in affected programs: 2485892 -> 2429074 (-2.29%) helped: 1097 HURT: 59 helped stats (abs) min: 2 max: 168 x̄: 51.96 x̃: 64 helped stats (rel) min: 0.12% max: 12.70% x̄: 3.44% x̃: 2.22% HURT stats (abs) min: 2 max: 16 x̄: 3.02 x̃: 2 HURT stats (rel) min: 0.18% max: 0.83% x̄: 0.64% x̃: 0.71% 95% mean confidence interval for cycles value: -51.04 -47.26 95% mean confidence interval for cycles %-change: -3.40% -3.07% Cycles are helped. Signed-off-by: Ian Romanick <<a href="mailto:ian.d.romanick@intel.com">ian.d.romanick@intel.com</a>> Reviewed-by: Lionel Landwerlin <<a href="mailto:lionel.g.landwerlin@intel.com">lionel.g.landwerlin@intel.com</a>></pre> </div> <hr> You are receiving this mail because: <ul> <li>You are the assignee for the bug.</li> <li>You are the QA Contact for the bug.</li> </ul> </body> </html>