egcs-971225, hpux9 pa/pa.c warning: comparisons like X<=Y<=Z ...

[Jeffrey A Law]

  In message < 199801021435.JAA11900@caip.rutgers.edu >you write:
  > 	When bootstrapping on hpux9 using -W -Wall, I got a warning
  > from pa/pa.c which looked odd.
  > 
  >  > ./config/pa/pa.c:420: warning: comparisons like X<=Y<=Z do not have
  >  > 	their mathematical meaning
Yes, this one has been on my "what the hell?!?" list for about 4 years.

arith_double_operand is only used by DImode expanders in pa.md;
furthermore, those expanders "FAIL" when either of their operands is
not a register.

It seems to me that we could just replace "arith_double_operand" with
"register_operand" in pa.md and remove arith_double_operand from pa.c.

jeff