Re: patch for core dump in cse with -O2 on x86

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

  In message <199810152125.RAA03116@blastula.phys.columbia.edu>you write:
  > 
  > The appended patch fixes a core dump in cse.  If HAVE_cc0 is defined,
  > fold_rtx may try to call equiv_constant with a null rtx.  This case is
  > triggered by skip_comment() in cpplib.c in the current source tree.
  > 
  > The patch makes equiv_constant return 0 in this case, which should be
  > sane.
  > 
  > zw
  > 
  > 1998-10-15 17:20 -0400  Zack Weinberg  <zack@rabi.phys.columbia.edu>
  > 
  > 	* cse.c (equiv_constant): Check for null argument.
Well, I'd like to know how this happened.  ie, is it supposed to be possible
for the compiler to get to equiv_constant with a null argument?

If yes, then the patch would be OK.

If no, then the problem lies elsewhere.

I can't judge which is correct without more information.

jeff