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Re: Some statement counts for gcc


On Sun, Aug 25, 2002 at 06:04:11PM -0500, Brad Lucier wrote:

>  branch prediction     : 165.11 (33%) usr   0.07 ( 1%) sys 165.50 (33%) wall
...
> A surprising (to me) number of lines in real.c are executed; I might look
> there to see what's going on.

The branch predictor uses emulated floating point numbers internally.
Jan Hubicka has explained why this is currently necessary -- can't
find the message at the moment though.  However, real.c is indeed
quite slow; I suspect that accounts entirely for the amount of time
spent in this patch

If I remember correctly this code has a very complicated flow graph,
and branch prediction may not help much; perhaps the right thing is
to detect code like this and disable that optimization.

zw


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