<html> <head> <base href="https://bugs.freedesktop.org/"> </head> <body> <div> <a class="bz_bug_link bz_status_REOPENED " title="REOPENED - [apitrace] Graphical artifacts in Civilization VI on RX Vega" href="https://bugs.freedesktop.org/show_bug.cgi?id=104602#c17">Comment # 17</a> on <a class="bz_bug_link bz_status_REOPENED " title="REOPENED - [apitrace] Graphical artifacts in Civilization VI on RX Vega" href="https://bugs.freedesktop.org/show_bug.cgi?id=104602">bug 104602</a> from <a class="email" href="mailto:t_arceri@yahoo.com.au" title="Timothy Arceri <t_arceri@yahoo.com.au>"> Timothy Arceri</a> <pre>After talking this over with Marek here is a summary of the problem. LLVM's VGPR indexing code on gfx9+ is broken for immediate arrays. Usually this is not a problem as GLSL IR in mesa will lower these to Uniforms via lower_const_arrays_to_uniforms(). However this does not work for the shaders in Civ6 because these arrays are not actually defined as constant arrays for example the original shader looks like this: vec4 x0[3]; vec4 x1[6]; vec4 x2[6]; vec4 x3[6]; x0[0].xy = vec2(0.031250, 0.500000); x0[1].xy = vec2(0.968750, 0.031250); x0[2].xy = vec2(0.968750, 0.968750); x1[0].xy = vec2(1.000000, 1.000000); x1[1].xy = vec2(0.000000, 1.000000); x1[2].xy = vec2(-1.000000, 0.000000); x1[3].xy = vec2(-1.000000, -1.000000); x1[4].xy = vec2(0.000000, -1.000000); x1[5].xy = vec2(1.000000, 0.000000); x2[0].xy = vec2(1.000000, -1.000000); x2[1].xy = vec2(2.000000, 1.000000); x2[2].xy = vec2(1.000000, 2.000000); x2[3].xy = vec2(-1.000000, 1.000000); x2[4].xy = vec2(-2.000000, -1.000000); x2[5].xy = vec2(-1.000000, -2.000000); Without SSA I don't see any way for GLSL IR to easily recognise this as a constant array. Unfortunately by the time LLVM is done it is recognised and is exposed to the buggy indexing support.</pre> </div> <hr> You are receiving this mail because: <ul> <li>You are the assignee for the bug.</li> </ul> </body> </html>