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Re: ia64 performance regression


  In message <20011016172801.B5704@redhat.com>you write:
  > On Tue, Oct 09, 2001 at 01:53:37PM -0700, Steve Christiansen wrote:
  > > What is the purpose of the following code in loop.c (loop_regs_scan)?
  > > 
  > >   for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
  > >     {
  > >       regs->array[i].may_not_optimize = 1;
  > >       regs->array[i].set_in_loop = 1;
  > >     }
  > 
  > I don't know.  Paranoia, probably.
FWIW, this code has been around since 1990 or earlier -- I ran into this on
the PA a decade or so ago.

I was relatively inexperienced with the optimizers themselves, so rather than
hack loop.c, I twiddled the PA backend to not expose the PIC register on
symbolic address computations, loads, and stores.

jeff



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