Hi On Wed, May 06, 2015 at 11:52:59AM -0700, Nick Lewycky wrote: > Newer versions of clang will allocate %rbx as one of the inline asm inputs,
Thats great > even in PIC. This occurs when building ffmpeg with clang -fsanitize=address > -O1 -fPIE. Because the asm does clobber %bx whether PIC is on or off, just > include %bx in the clobber list regardless of whether PIC is on or off. you cant include *bx in the clobber list with PIC it breaks compilers that are less great, like gcc gcc (Ubuntu/Linaro 4.6.3-1ubuntu5) 4.6.3 ../libswscale/x86/hscale_fast_bilinear_simd.c: In function ‘ff_hyscale_fast_mmxext’: ../libswscale/x86/hscale_fast_bilinear_simd.c:205:5: error: PIC register clobbered by ‘%ebx’ in ‘asm’ ../libswscale/x86/hscale_fast_bilinear_simd.c: In function ‘ff_hcscale_fast_mmxext’: ../libswscale/x86/hscale_fast_bilinear_simd.c:276:5: error: PIC register clobbered by ‘%ebx’ in ‘asm’ also what exactly are you trying to fix ? or rather what exactly goes how exactly wrong with the code as it is if rbx is used ? also ideally changes to this code should be tested against gcc/clang/icc of various versions with and without PIC, 32 and 64 bit this code is more tricky than than the average so theres a good change changes to it will break some compiler [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB What does censorship reveal? It reveals fear. -- Julian Assange
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