<html> <head> <base href="https://bugs.freedesktop.org/"> </head> <body> <div> <a class="bz_bug_link bz_status_NEW " title="NEW - [radeonsi] playing back videos with VDPAU exhibits deinterlacing/anti-aliasing issues not visible with VA-API" href="https://bugs.freedesktop.org/show_bug.cgi?id=97988#c11">Comment # 11</a> on <a class="bz_bug_link bz_status_NEW " title="NEW - [radeonsi] playing back videos with VDPAU exhibits deinterlacing/anti-aliasing issues not visible with VA-API" href="https://bugs.freedesktop.org/show_bug.cgi?id=97988">bug 97988</a> from <a class="email" href="mailto:maraeo@gmail.com" title="Marek Olšák <maraeo@gmail.com>"> Marek Olšák</a> <pre>Thanks Grigori. GLSL: color = fract(gl_FragCoord.y / 2) < 0.5 ? texture(texture0, texcoord0) : texture(texture1, texcoord0); texture0 and texture1 are SMEM loads. LLVM (SimplifyCFG) transforms it to: color = texture(fract(gl_FragCoord.y / 2) < 0.5 ? texture0 : texture1, texcoord0); That's a nice transformation. You don't have to use 2 SMEM loads, you can just use one SMEM load depending on the result of the condition. The problem is gl_FragCoord.y is a VGPR and texture0/1 are SGPRs, therefore flat VMEM loads are used to load the descriptors. However, image_sample requires descriptors in SGPRs, so v_readfirstlane is used. That effectively uses the result of the condition from the first active lane, discarding the results from all other lanes. The result would be exactly the same if the compiler did: v_readfirstlane s0, gl_FragCoord.y; The test case seems pretty trivial I wonder how many other apps are affected.</pre> </div> <hr> You are receiving this mail because: <ul> <li>You are the assignee for the bug.</li> </ul> </body> </html>