This is the mail archive of the
mailing list for the GCC project.
On 2005-01-01, at 17:53, Zdenek Dvorak wrote:
I think Richard means issuing warning in case where
-funsafe-loop-optimizations causes us to ignore some conditions
for optimizations we were not able to prove. Which definitely is
a good idea.
Micro tweaking on this level isn't supposed to be done on the scope of
files/compilation units. Perhaps a pragma directive allowing to get
better assembler output
from a particular carefully selected part of the code after profiling
could be of some use:
#pragma begin tighten code
// We don't give a sh*t about the speed, since it's string parsing
// and we do it only once here. Better generate compact code to
// on this microcontroller here.
#pragma end tighten code
/* Uff, I didn't have to go to assembler coding on this DSP, since I
discovered that the
* following pragma did result in sufficiently performing code output by
* a margin of 5%... The video doesn't stutter anymore...
#pragma begin assume infinite arithmetic domains
int fft(unsigned int *real, unsigned int *imaginary, unsigned int
/* butterfly... butterfly... */
#pragma end assume infinite arithmeric domains