Re: More than you ever wanted to know about Fortran array indexing ;-)

[Jeffrey A Law <law at cygnus dot com>]

  In message <9710080552.AA13313@moene.indiv.nluug.nl>you write:
  > I wrote that that would be a nice follow on project, but it turns  
  > out that gcc already knows how to do that; unfortunately, the  
  > function that decides about this optimisation almost never applies it.
  > 
  > I am talking about `combine_givs_p' in loop.c.  Basically it says:  
  > If a giv G2 can be expressed as a function of giv G1 and that  
  > function is a valid address expression, and the resulting addressing  
  > mode is cheaper than the original, then do not reduce G2.
Yes.  On a somewhat related note, as I've mentioned, with my patch to
handle more complex givs (aka the USE patch) I generally get worse code
on my PA.  I _believe_ this is due to loop not realizing that many givs
are related and due to the giv cost/benefit analysis not handling more
complicated givs.

jeff