Jason Ekstrand
37703040a1
The idea here is that fusing multiply-add combinations too early can reduce our ability to perform CSE and value-numbering. Instead, we split ffma opcodes up-front, hope CSE cleans up, and then fuse after-the-fact. Unless an algebraic pass does something silly where it inserts something between the multiply and the add, splitting and re-fusing should never cause a problem. We run the late algebraic optimizations after this so that things like compare-with-zero don't hurt our ability to fuse things. shader-db results for fragment shaders on Haswell: total instructions in shared programs: 4390538 -> 4379236 (-0.26%) instructions in affected programs: 989359 -> 978057 (-1.14%) helped: 5308 HURT: 97 GAINED: 78 LOST: 5 This does, unfortunately, cause some substantial hurt to a shader in Kerbal Space Program. However, the damage is caused by changing a single instruction from a ffma to an add. This, in turn, *decreases* register pressure in one part of the program causing it to fail to register allocate and spill. Given the overwhelmingly positive results in other shaders and the fact that the NIR for the Kerbal shaders is actually better, this should be considered a positive. Reviewed-by: Matt Turner <mattst88@gmail.com>
File: docs/README.WIN32 Last updated: 21 June 2013 Quick Start ----- ----- Windows drivers are build with SCons. Makefiles or Visual Studio projects are no longer shipped or supported. Run scons libgl-gdi to build gallium based GDI driver. This will work both with MSVS or Mingw. Windows Drivers ------- ------- At this time, only the gallium GDI driver is known to work. Source code also exists in the tree for other drivers in src/mesa/drivers/windows, but the status of this code is unknown. Recipe ------ Building on windows requires several open-source packages. These are steps that work as of this writing. - install python 2.7 - install scons (latest) - install mingw, flex, and bison - install pywin32 from here: http://www.lfd.uci.edu/~gohlke/pythonlibs get pywin32-218.4.win-amd64-py2.7.exe - install git - download mesa from git see http://www.mesa3d.org/repository.html - run scons General ------- After building, you can copy the above DLL files to a place in your PATH such as $SystemRoot/SYSTEM32. If you don't like putting things in a system directory, place them in the same directory as the executable(s). Be careful about accidentially overwriting files of the same name in the SYSTEM32 directory. The DLL files are built so that the external entry points use the stdcall calling convention. Static LIB files are not built. The LIB files that are built with are the linker import files associated with the DLL files. The si-glu sources are used to build the GLU libs. This was done mainly to get the better tessellator code. If you have a Windows-related build problem or question, please post to the mesa-dev or mesa-users list.