Re: local-alloc update_equiv_regs and moving register initialization

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

  In message <7334.968972585@upchuck>you write:
  > 
  > 
  >   In message <200009142244.SAA18278@jwlab.FEITH.COM>you write:
  >   > update_equiv_regs has the comment:
  >   > 
  >   >   /* Now scan all regs killed in an insn to see if any of them are
  >   >      registers only used that once.  If so, see if we can replace the
  >   >      reference with the equivalent from.  If we can, delete the
  >   >      initializing reference and this register will go away.  If we
  >   >      can't replace the reference, and the instruction is not in a
  >   >      loop, then move the register initialization just before the use,
  >   >      so that they are in the same basic block.  */
  >   > 
  >   > Why isn't desirable to move the register initialization just before the
  >   > use when both are within the same loop?
  > Doesn't that minimize the lifetime of the pseudo holding the initialized
  > value, which in turn gives the allocators more freedom in making
  > register assignments?
Please ignore my answer.  I mis-parsed the question.

jeff