Re: genattrtab for ia64

[Vladimir Makarov <vmakarov at redhat dot com>]

Richard Kenner wrote:
> 
> Why does it use over 200 MB of memory and take over 15 minutes of CPU time on
> a moderately-fast machine?

I think it is a generation of DFA pipeline hazard recognizer (it is
implemented in genautomata.c).

It takes 2m50s on a 900Mhz Itanium2 machine.  It is a small part of all
compiler build time.  But the advantages of usage of DFA pipeline hazard
recognizer is bigger.  The code generated by gcc with the DFA pipeline
hazard recognizer is 3% faster for SPECINT2000 on Itanium2 and gcc
itself is 60% faster.  Generally speaking, genautomata.c makes a lot of
work what gcc did earlier during compiling each file. It is made once
during building the compiler.

I understand that is inconvenient for gcc developers but gcc users win a
lot which is more important with my point of view.  I think there are
still opportunities to decrease memory consumption and it will be on my
TODO list.

Vlad