Re: large peephole2 speedup.

[Richard Henderson <rth at cygnus dot com>]

On Tue, Apr 11, 2000 at 05:39:40PM -0700, Richard Henderson wrote:
> You could instrument genconfig to emit a variable in the same
> vein as MAX_INSNS_PER_SPLIT that counts the maximum number of
> input insns to a peephole2 pattern.

Expanding on this, one could have an array

  regset peep2_live_at[MAX_INSNS_PER_PEEP2+1];

peep2_live_at[N] is the set of live registers before the Nth insn
in the matched sequence.  As you search for matches, you shift
each regset down one slot, recycling them at the end.  Or probably
better, don't actually shift the regsets, just have a "current offset"
and do modulo addressing.

Now you're not analysing any insn more than once.



r~