my bct loop hacks

[David Edelsohn]

	I am testing out the re-integration of the BCT code with the
current version of EGCS in CVS.  With my version of loop.c prior to the
check_dbra_loop() changes in August, loop_iterations() discovered the
number of iterations for normal loops.  With the current version of loop.c
from CVS, loop_iterations() always is failing with "No final conditional
branch found".  This is outside my changes and basically means that no
constant number of iterations can be discovered anymore.  BCT insertion
then fails.

	I do not know what is going on with the loop reversal changes, but
this lack of iteration information not only disables the low-overhead loop
instructions but all loop unrolling as well.

David