Re: c++ speed 3.3/4.0/4.1

[howarth at bromo dot msbb dot uc dot edu (Jack Howarth)]

     Well I tried a few different builds of xplor-nih tonight with the 
following optimization flags for the gcc and g++ compilers...
                                                        testsuite in seconds
                                                      xplor    python   tcl
-O3 -ffastmath -mtune=970                             137.5454 128.7770 48.0390
-O3 -ffastmath -mtune=970 -fno-threadsafe-statics     137.0741 127.4653 48.0205
-O3 -ffastmath -mtune=970  -finline-limit=1200        135.4462 127.5790 48.3680

As you can see the c/c++ code (mostly c++) in xplor-nih is immune to
improvement in gcc 4.2.0 with the -fno-threadsafe-statics and
-finline-limit=1200. The same build using Apple's gcc 3.3 would execute about
7% faster.
     Is there anything not usually enabled in -O3 that might help? I am
rather confused by the options...

  -ftree-vectorize
  -fipa-cp 

and the rest as to which ones are part of -O3 in gcc 4.2.0 and which require
enabling (as well as which are incompatible with each other). I would be
interested in trying to squeeze some more performance out of the gcc 4.2.0
compiles but am at a loss for the logical approach to doing this (short of
resorting to -fprofile-use).
       Thanks in advance for any other advice.
                    Jack