[FFmpeg-devel] [PATCH] Optimization of original IFF codec

Ronald S. Bultje rsbultje
Sun Apr 25 23:30:56 CEST 2010


Hi,

On Sun, Apr 25, 2010 at 5:27 PM, Sebastian Vater
<cdgs.basty at googlemail.com> wrote:
> Well, gcc could think that b is modified in the loop otherwise, const
> tells the compiler to be 100% sure, it will ever be changed...and that's
> what I want!

Check the disassembly if in doubt. You'll see gcc only calculates it
once (gdb ffmpeg; disassemble decode_frame_ilbm or disassemble
decodeplane8/32, depending on whether gcc inlined it, which it
probably did).

Ronald



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