<html> <head> <base href="https://bugs.freedesktop.org/"> </head> <body> <div> <a class="bz_bug_link bz_status_NEW " title="NEW - [ANV] The Witcher 3 shadows flickering" href="https://bugs.freedesktop.org/show_bug.cgi?id=109404#c18">Comment # 18</a> on <a class="bz_bug_link bz_status_NEW " title="NEW - [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:danylo.piliaiev@gmail.com" title="Danylo <danylo.piliaiev@gmail.com>"> Danylo</a> <pre>What have I found on Friday: The NIR I have attached is not a problem - it's a correct one as Jason corrected me on IRC. The issue seems to be even further down, in native code such comparison generated: asr.le.f0.0(8) null<1>D -g0<0,1,0>W 15D { align1 1Q }; ... (+f0.0) if(8) JIP: 128 UIP: 128 { align1 1Q }; The 15th bit of that register means: 0: Front Facing 1: Back Facing Then it is negated to have: 0: Back Facing ~0: Front Facing Then the *signed* .le (less or equal) with zero, as I see it - this is the wrong part, ~0 < 0 when comparison is signed however the initial intention was to have "false" in this comparison when triangle is front facing. Manually changing null<1>D to null<1>UD fixes the issue. How such comparison is created? brw_fs_cmod_propagation.cpp, in opt_cmod_propagation_local, line 323 - CONDITION_LE modifier is propagated when condition operates on two REGISTER_TYPE_UD while scan_inst (opcode: asr) has dst: REGISTER_TYPE_D and src: REGISTER_TYPE_W. >From my point of view it's not a correct thing to do, but I'm not sure what to do here.</pre> </div> <hr> You are receiving this mail because: <ul> <li>You are the QA Contact for the bug.</li> <li>You are the assignee for the bug.</li> </ul> </body> </html>