Re: [RFA, PATCH, PowerPC] Implements PowerPC e500mc core support

[David Edelsohn <dje at watson dot ibm dot com>]

	Also, let me point out that the e500mc machine description already
omits some instances of the retirement state on FP descriptions to keep
the automata a reasonable size.  I am proposing removing "retire" from a
few more FP patterns.

	There are two problems with generating the DFAs.  One is that very
long pipelines, frequently with lots of nop cycles before retirement,
produce extremely large automata.  Those large automata with many states
require a long time to generate.

	The second problem is that although most, if not all machine
descriptions, localize each class of processors and associated automata to
a file with all of the information self-contained.  genautomata does not
utilize this locality, reads the entire machine description, generating
all of the automata in memory and writes all of the automata at once.
This is not scalable.  The PowerPC machine description currently tops out
at over 300MB of data on both AIX and PPC Linux.

	The latter can be solved with something like a new GCC DFA
keyword, such as "dfa_flush", which would write out the automata and free
the automata data structures in memory.  This does not solve the time and
size of individual automata.

David