[Bug rtl-optimization/8361] [3.3/3.4/4.0 regression] C++ compile-time performance regression

["ghazi at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>]

------- Additional Comments From ghazi at gcc dot gnu dot org  2005-02-06 18:08 -------
If you want to compare how the memory footprint has affected performance, use 
these flags in 3.3 and later:

--param ggc-min-expand=30 --param ggc-min-heapsize=4096

Those are the hardcoded values that 3.2 uses to tune how often the collector 
runs.  I would be interested to see how later versions behave when supplied 
these flags, this will simulate how fast we compile on memory constrained boxes 
relative to 3.2.

Another perhaps more interesting test (but one which will take slightly more 
effort for you) would be to see how raising these values in 3.2 will affect 
performance.  Some distros (RH?) did in fact raise them in their releases so 
users may be comparing their cranked distro gcc-3.2 to our FSF releases.

Of course since these values are hardcoded in 3.2, you'd have to rebuild that 
compiler, however I think an apples-to-apples comparsion is in order before 
closing this PR.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=8361