> Am 28.05.2020 um 12:37 schrieb Martin Storsjö <mar...@martin.st>: > >> On Mon, 25 May 2020, Martin Storsjö wrote: >> >>> On Sun, 24 May 2020, Carl Eugen Hoyos wrote: >>> >>> Am So., 24. Mai 2020 um 21:53 Uhr schrieb Martin Storsjö >> <mar...@martin.st>: >>> >>>> configure --enable-gpl --arch=i686 --cc=clang-cl --ld=lld-link >>>> --target-os=win32 --toolchain=msvc --enable-cross-compile --ar=llvm-ar >>>> --nm=llvm-nm --disable-stripping --extra-cflags=-m32 >>> >>> Why are you cross-compiling? >>> On which system are you testing this? >> >> Because I normally only ever cross compile for windows. >> >> There seems to be a subtle difference in this case, between using clang-cl >> and "clang -target i686-win32-msvc"; clang-cl passes "-mdisable-fp-elim" to >> the compiler internals, while "clang -target i686-win32-msvc" doesn't. >> >> And cross compiling does seem to affect this particular case; there's a >> check for whether ebp is available, which requires running the built >> executable. When cross compiling, it's assumed the built executable is ok >> and it isn't test run. >> >> So with clang-cl running on windows, you'll end up with "#define >> HAVE_EBP_AVAILABLE 0" in config.h, and the x86 cabac code won't end up used >> at all - i.e. this patch wouldn't make any difference. >> >> With clang-cl in cross compilation, and other invocations of "clang" instead >> of "clang-cl", targeting i686 windows, you'll end up with ebp_available >> enabled. >> >> For a case where it does make a difference, in the same setup, try >> configuring this way instead: >> >> --cc='clang -target i686-win32-msvc' --ld=lld-link >> --extra-ldflags='msvcrt.lib oldnames.lib' --toolchain=msvc >> >> In this case, the ebp_available test will succeed, it will proceed to trying >> to build the x86 inline cabac code, which fails. > > Any further comments on this patch?
Please wait a few days more, I am not happy about the patch and at least I’d like to understand better why this is a good and why there is no alternative. Carl Eugen _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
