Re: remarks about g++ 4.3 and some comparison to msvc & icc on ia32

["Richard Guenther" <richard dot guenther at gmail dot com>]

On 1/28/07, tbp <tbptbp@gmail.com> wrote:
> Let it be clear from the start this is a potshot and while those
> trends aren't exactly new or specific to my code, i haven't tried to
> provide anything but specific data from one of my app, on
> win32/cygwin.
>
> Primo, gcc getting much better wrt inling exacerbates the fact that
> it's not as good as other compilers at shrinking the stack frame size,
> and perhaps as was suggested by Uros when discussing that point a pass
> to address that would make sense.
> As i'm too lazy to properly measure cruft across multiple compilers,
> i'll use my rtrt app where i mostly control large scale inlining by
> hand.
> objdump -wdrfC --no-show-raw-insn $1|perl -pe 's/^\s+\w+:\s+//'|perl
> -ne 'printf "%4d\n", hex($1) if /sub\s+\$(0x\w+),%esp/'|sort -r| head
> -n 10
>
> msvc:2196 2100 1772 1692 1688 1444 1428 1312 1308 1160
> icc: 2412 2280 2172 2044 1928 1848 1820 1588 1428 1396
> gcc: 2604 2596 2412 2076 2028 1932 1900 1756 1720 1132

It would have been nice to tell us what the particular columns in
this table mean - now we have to decrypt objdump params and
perl postprocessing ourselves.

(If you are interested in stack size related to inlining you may want
to tune --param large-stack-frame and --param large-stack-frame-growth).

Richard.