gcc-2.7 creates faster code than pgcc-1.1.1

[Jeffrey A Law]

  In message < 199903050104.UAA15335@octiron.phys.columbia.edu >you write:
  > A related issue:  I see us generate a lot of code like this for loops over
  > strings:
  > 
  > loop:
  > 	xorl %eax, %eax
  > 	movb (%esi), %al
  > 	incl %esi
  > 	movb %al, (%edi)
  > 	incl %edi
  > 	testl %eax
  > 	jne loop
  > 
  > After the first iteration, the xorl is unnecessary.  We ought to be able to
  > hoist it out of the loop.
True, but I don't believe the loop optimizer is prepared to do that since it
doesn't keep track of what bits are active vs what bits are inactive in a 
value.

jeff