[flac-dev] GCC generates slow code for IA32

[Martijn van Beurden]

On 22-09-13 10:31, lvqcl wrote:
> I measured encoding speed of 24-bit WAV files. It turns out that 32-bit
> encoder made by GCC is ~1.7x times slower than 32-bit encoder made by MSVS.

Strange, I'm not able to reproduce your findings. I did found something 
rather odd though. I thought MSVC, ICL and GCC would produce the same 
files, but for some reason a GCC compile creates slightly smaller files. 
Looks like there is some GCC-specific code that influences compression 
ratio? I haven't noticed that in any of the tests I did before. GCC is a 
bit slower, but nowhere near 1.7x

Results are here: 
http://www.icer.nl/misc_stuff/compare-24-bit-speed-across-compiles.pdf

These results are from an MinGW compile (GCC 4.6.1 AFAIK), MSVC 2012 and 
ICL 13 compiles of FLAC 1.3.0 without any modifications. These are all 
32-bit executables run on a 64-bit Windows 7 system. The graphs show 
encoding and decoding performance on Lord of the Rings: The Two Towers 
(The Complete Recordings) in 44/16 and 48/24, and Nine Inch Nails' The 
Slip in 44/16 and 96/24. See the graph titles.
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