#493 mcs51/peeph - fix volatile guards and typo

[Konstantin Kim]

mcs51/peeph.def: fix volatile guards and typo
4 fixes in mcs51/peeph.def:

140 : replacement reads @%2 twice, original once - notVolatile
143.b : the replacement instruction is rr a, not rc a - comment 'rc' -> 'rr'
211 : push/pop removal must not skip volatile read - notVolatile %1
247.h : typo: surrounding context all uses r%5 - @r%4 -> @r%5

All condition additions make rules stricter (fire less often), never looser.
More rules need notUsed('a') / notUsed('c') guards but mcs51notUsed() only supports r0-r7.

mcs51/peep.c: fix typo in ar0-ar7 filter
Line 888: what[0] == 'a' && what[0] == 'r' is always false. Should it be what[1] == 'r' ?

any review is appreciated

[Philipp Klaus Krause]

I've had a look at your patches. They make sense to me. I've tried them.

• mcs51_peeph.def.patch is in [r16432].
• mcs51_peep.c.patch results in regression test failures; I guess it triggers issues (or missing functionality) elsewhere in the mcs51 peephole optimizer or its rules.