Terry Lambert([EMAIL PROTECTED])@2001.06.22 20:38:45 +0000:
> "Karsten W. Rohrbach" wrote:
> > btw, regarding gcc's -O2 optimization breakage on -2.95.x and improved
> > instrumentation of the new compiler kit, is there someone working on
> > getting gcc-3.0 into -current?
> > ...yes *sigh* i know, 3.0 is _not_ stable, neither is -current ;-)
> Does it do tail-call optimization? Last I checked, this
> was only supported under i986.
refer to http://www.gnu.org/software/gcc/gcc-3.0/features.html
General Optimizer Improvements:
- Basic block reordering pass.
- New if-conversion pass with support for conditional (predicated)
- New tail call and sibling call elimination optimizations.
- New register renaming pass.
- New (experimental) static single assignment (SSA) representation
- New dead-code elimination pass implemented using the SSA representation.
- Global null pointer test elimination.
- Global code hoisting/unification.
- More builtins and optimizations for stdio.h, string.h and old BSD
functions, as well as for ISO C99 functions.
- New builtin __builtin_expect for giving hints to the branch predictor.
> It would be a _SERIOUS_ win, for a lot of stuff.
yes, i compiled it in a sandbox here just to look how some userspace
stuff for embedded use compiles and runs (let's call it "empiric
approach"), just to see whether it breaks some stuff or not and from
what i saw the files were very compact (due to dwarf2 debug symbols that
keep debug information very small), but the code also. with some tiny
binaries it came to an average of approx. 90% code size compared to
2.95.2 (stripped) binaries. also execution _seems_ to be quicker with
stuff that dynamically allocates mem and calls to shared objects/libs.
i did not yet have the time to look into the intrinsics but i was kinda
stunned about the improvements. next week when i am back in the office
i'll try to compile xfree4 just to see if it breaks something ;-)
have a nice weekend
> -- Terry
> cd /pub; more beer
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