On Wed, Aug 24, 2005 at 06:50:25PM +0530, Ashwin wrote: > The pattern matches in the original peephole pass because the > peephole pass happens just before assembly generation, when the 3 insns > are present together. Has anybody encountered a similar problem?
No, or at least havn't looked. > Does this mean that peephole2 and peephole both should be kept on. No. It would be possible to run peep2 more than once. Noone has shown a need for it yet. > Secondly, after taking a look at other ports, i realised that all are > using peep2_dead_reg_p instead of dead_or_set_p to check if a register > is dead. The former is smarter than the later in the sense that it also > checks if the current insn "sets" the register which is to be verified > as dead. So, why do other ports use peep2_reg_dead_p instead of > dead_or_set_p. Pls help me to find the advantages of using > peep2_reg_dead_p over its counterpart. My guess is that your misunderstanding is that you're not realizing that you can ask peep2_dead_reg_p about the state of a register at the beginning of the N+1 insn in the sequence. That is, after the entire sequence is over. peep2_dead_reg_p *is* smarter than dead_or_set_p. r~
