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opt_constant_folding is supposed to fold trees of constants into a single constant. Surprisingly, it was also propagating constant values from variables into expression trees - even when the result couldn't be folded together. This is opt_constant_propagation's job. The ir_dereference_variable::constant_expression_value() method returns a clone of var->constant_value. So we would replace the dereference with a constant, propagating it into the tree. Skip over ir_dereference_variable to avoid this surprising behavior. However, add code to explicitly continue doing it in the constant propagation pass, as it's useful to do so. shader-db statistics on Broadwell: total instructions in shared programs: 8905349 -> 8905126 (-0.00%) instructions in affected programs: 30100 -> 29877 (-0.74%) helped: 93 HURT: 20 total cycles in shared programs: 71017030 -> 71015944 (-0.00%) cycles in affected programs: 132456 -> 131370 (-0.82%) helped: 54 HURT: 45 The only hurt programs are by a single instruction, while the helped ones are helped by 1-4 instructions. Signed-off-by: Kenneth Graunke <kenneth@whitecape.org> Reviewed-by: Ian Romanick <ian.d.romanick@intel.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.