more on fortran array indexing

[Richard Henderson <rth@cygnus.com>]

Last night I examined the differences in the output of the 
friendlier FASTER_ARRAY_REFS, and the patched expr.c ARRAY_REF.

They output, respectively,

   addr = ((n*64)/8 * (j-1)) + (i*8) + base - 8

and

   addr = (i-1)*8 + ((j-1) * (n*64)) / 8 + base

IMO, it is obviously the FLOOR_DIV 8 that is causing the problem.

Question: Why in the world are arrays indexed as bits?  There
seems to me to be very little use for such a thing, and a front
end that would need it could build it out of simpler constructs, no?

Or perhaps add a flag to TYPE to indicate whether the array is
indexed via bytes or bits to get rid of this lossage where it isn't
needed.  Note that even in the FASTER_ARRAY_REFS case, there is 
still the divide in the asm output -- we were able to reduce it
out of the loop, but not eliminate it.

Comments?


r~