Hello The -funswitch-loops Option seem work on gcc 4.3.0 and above not good for speed.Test on m68k gcc.
It generate much larger code(wma123) and code is slower in many case (try out ffmpeg H264 decode)i get report from a Athlon 2600+ with single channel ram running amiga 68k emulator. But on my System use a AMD64 3000+ and Dual Channel ram running amiga emulator -funswitch-loops cause only large files but no slowdown. but i guess on a real 68k/coldfire CPU without 2. level cache, -funswitch-loops is more not optimal. gcc 3.4.0 have too this option set on -O3 or i am wrong ? and here the speed is better and code is smaller Is there a way to tweak some values on backend for specific CPU so -funswitch-loops works 3.4.0(maybe unroll not so much loops ? for now best solution for speed (H264 decode work on the system with single Channel ram same ot little faster as 3.4.0 build.) is let disable -funswitch-loops disable as far i get speedvalue reports. here are some values that show too slowdown on compilers 4.2.4 and 4.3.0 but on X86 http://multimedia.cx/eggs/compiler-performance-profiling-with-ffmpeg/ Regards
