2011/12/5 Michael Karcher <freedesktop-bugzi...@mkarcher.dialup.fu-berlin.de>: > Am Montag, den 05.12.2011, 13:03 -0800 schrieb Stéphane Marchesin: >> > This translation is correct. The mentioned optimization now kicks in >> > corrrectly removing line 9, but it also reokaces line 6/7 by >> > 6: R[1].xyz = MUL R[0], T_DIFFUSE >> > This does yield the correct result in R[1].xyz, but it does (of course) >> > not update R[0].xyz, which is a problem, because R[0].xyzz is used in >> > line 16. In this special case, we could get away with renaming R[0].xyzz >> > into R[1].xyzz in line 16, but in the general case, there is no warranty >> > that R[1].xyz still contains in line 16 what it did in line 7. >> > >> > Any suggestions? Just remove this optimization? Improve the optimizer to >> > have it check that the eliminated temporary is not used in any further >> > lines? >> >> Yeah we need to replace the temporary in all further lines. Patches welcome. > Thanks for your quick response! > > How can you be sure that R[1].xyz keeps unchanged in all further lines, > so it is a valid replacement for the elided R[0].xyz? The fragment > shader language is not static single assignment, so R[1] could already > have been reused for a different purpose. >
Yeah, I have been working on a liveness analysis branch to solve that. As a quicker fix we could just disable the optimization when the register gets touched later. Stéphane _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
