Patch for incorrect execute/divconst-2.c)

[Jeffrey A Law]

  In message < 200005301054.LAA23604@cam-mail2.cambridge.arm.com >you write:
  > 
  > geoffk@cygnus.com said:
  > > Sure.  Assuming that DImode is 2*HOST_BITS_PER_WIDE_INT wide, - (1 <<
  > > (HOST_BITS_PER_WIDE_INT - 1) is a CONST_INT, and (1 <<
  > > (HOST_BITS_PER_WIDE_INT - 1) is a CONST_DOUBLE.   CONST_INTs are
  > > sign-extended, so that -1 has the same representation in all modes.
  > 
  > 
  > I've never seen anything like this written down before (not that I'm 
  > disputing what you are saying).  Can you add something like this to 
  > rtl.texi (under const_double) to make this explicit.
Sounds like the right thing to do. We have notes about this stuff all
over the sources, but not in the manual itself.

jeff