On Thu, Feb 19, 2015 at 05:13:19PM +0000, Carl Eugen Hoyos wrote: > Hendrik Leppkes <h.leppkes <at> gmail.com> writes: > > > > Attached patch by Francisco Blas Izquierdo Riera > > > fixes a compilation error in mlpdsp_init.c with > > > -fstack-check and some gcc compilers (I reproduced > > > the issue with gcc 4.7.3) by simplifying the code. > > > I ran some benchmarks with a very large thd file, > > > 'time' confirms the results of '-benchmark'. > > > > Please benchmark ASM changes using STAR/STOP_TIMER > > macros. > > It's 5400 without vs 5500 decicyles with the patch > attached. > > I (still) find it very hard to understand that > testing a few bytes of input data has more > meaning than running decoding several GBs > several times. > > > Looking at the code, the change introduces one > > extra instruction in x64, and is identical in x86, > > so I don't really see how it can be faster? > > I am not claiming it is faster. > Just that a slowdown is not reproducible.
something like this can possibly be used to fix build of the file
until someone rewrites it to yasm
diff --git a/libavcodec/x86/Makefile b/libavcodec/x86/Makefile
index 7c4f4cd..b96b2ea 100644
--- a/libavcodec/x86/Makefile
+++ b/libavcodec/x86/Makefile
@@ -164,3 +164,5 @@ YASM-OBJS-$(CONFIG_VP9_DECODER) +=
x86/vp9intrapred.o \
x86/vp9lpf.o \
x86/vp9mc.o
YASM-OBJS-$(CONFIG_WEBP_DECODER) += x86/vp8dsp.o
+
+$(SUBDIR)x86/mlpdsp_init.o: CFLAGS := $(subst -fstack-check, -fno-stack-check,
$(CFLAGS))
[...]
--
Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
There will always be a question for which you do not know the correct answer.
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