Large shaders using UBOs take a long time to compile
Submitted by Ian Romanick
Assigned to Intel 3D Bugs Mailing List
Created attachment 106510 Sample shader
For example, the attached shader-runner test took 25 minutes on my IVB laptop. On a debug build of Mesa (with -O1), Sysprof says that ~90% of the time is spent in brw::vec4_live_variables::compute_live_variables().
Changing the test to do
pass = !(condition) && pass;
if (condition) pass = false;
appears to end the slaughter.
Attachment 106510, "Sample shader":