prinft performance problem
code at klickverbot.at
Tue Mar 18 13:34:03 PDT 2014
On Tue 18 Mar 2014 04:31:30 AM CET, bearophile wrote:
> I have reduced another performance problem, Windows 32 bit.
> A test C program: […]
LDC/Win32 uses the MinGW output/formatting functions, as e.g. the
printf() from the MSCRT can't handle reals.
I don't really see a reason why the LDC-generated code should be that
much slower otherwise (you can verify this by just calling
__mingw_printf directly or I think also by passing the -posix/-ansi
flags to GCC).
As to why the MinGW printf() is actually slower, no idea. Probably just
a question of an optimized-to-hell version against a simple hack to
make the C99 format specifiers work.
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