<html> <head> <base href="https://bugs.freedesktop.org/"> </head> <body> <div> <a class="bz_bug_link bz_status_NEW " title="NEW - Too many temporary expressions in shader freeze glLinkProgram" href="https://bugs.freedesktop.org/show_bug.cgi?id=94477#c9">Comment # 9</a> on <a class="bz_bug_link bz_status_NEW " title="NEW - Too many temporary expressions in shader freeze glLinkProgram" href="https://bugs.freedesktop.org/show_bug.cgi?id=94477">bug 94477</a> from <a class="email" href="mailto:lemody@gmail.com" title="Tapani Pälli <lemody@gmail.com>"> Tapani Pälli</a> <pre>(In reply to Matt Turner from <a href="show_bug.cgi?id=94477#c8">comment #8</a>) > (In reply to Tapani Pälli from <a href="show_bug.cgi?id=94477#c6">comment #6</a>) > > Created <a href="attachment.cgi?id=126170" name="attach_126170" title="fix">attachment 126170</a> <a href="attachment.cgi?id=126170&action=edit" title="fix">[details]</a> <a href='page.cgi?id=splinter.html&bug=94477&attachment=126170'>[review]</a> [review] [review] > > fix > > > > This should result in same effect as the first experimentation, I will run > > testing on this and if it works fine then I'll send it to mesa-dev mailing > > list. > > That's pretty clever, but unfortunately it cannot work. Cases of dividing by > zero, inf, nan, etc cannot be handled. We don't do this optimization in > opt_algebraic for exactly that reason. right .. I knew there to be something missing as it was too good to be true :) > On top of that, the purpose of the test is to check whether you can compile > a huge expression, and the one it uses is hilariously unrepresentative and > prone to abuse by hacks like this one :) > > The test has uncovered real flaws in our compiler: GLSL IR's copy > propagation runs in O(n^2), and the channel_expressions pass creates a huge > number of expressions. > > Ken and I have spent time recently trying to handle the shader-db > regressions by disabling channel_expressions. It's slow going and other > tasks keep taking priority. > > The most direct way forward then, is to improve copy propagate's run time > like I described in <a href="show_bug.cgi?id=94477#c3">comment 3</a>. Maybe you want to take a stab at replacing > the linked lists in the pass with hash tables? I spent some time on it... > maybe you'll have better luck. :) I made a wrapper class for 'acp' that internally uses hash table but provides some methods of exec_list (just to easily experiment with this). I'm seeing some performance gains but not nearly as big as with my hack. I'll try to do the same for 'propagation_elements' and see if total effect would be big enough to continue with this exercise.</pre> </div> <hr> You are receiving this mail because: <ul> <li>You are the QA Contact for the bug.</li> </ul> </body> </html>