From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jeffrey A Law <law@cygnus.com>
To: drepper@cygnus.com (Ulrich Drepper)
Cc: egcs@cygnus.com
Subject: Re: internal error asm 
Date: Tue, 24 Feb 1998 05:07:00 -0000
Message-id: <28608.888305519@hurl.cygnus.com>
References: <r2iuq6ggb9.fsf@happy.cygnus.com>
X-SW-Source: 1998-02/msg01112.html

  In message < r2iuq6ggb9.fsf@happy.cygnus.com >you write:
  > Hi,
  > 
  > the following little piece of code crashed all gcc versions on ix86
  > which I could test:
  > 
  > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  > #include <stdio.h>
  > 
  > extern double bar (double);
  > 
  > int
  > baz (double d)
  > {
  >   double e = bar (d);
  > #ifdef BROKEN
  >   asm volatile ("" : : : "st");
  > #else
  >   asm volatile ("" : : : "memory");
  > #endif
  >   return printf ("%lg\n", e);
  > }
Thanks.  It's an x86 specific failure (dies in reg-stack...)

Can you test this patch (both to make sure it fixes the abort *and*
that it doesn't obviously screw up the code -- there's some question
in my mind about what is the proper thing to do in this case.

Index: reg-stack.c
===================================================================
RCS file: /egcs/carton/cvsfiles/egcs/./gcc/reg-stack.c,v
retrieving revision 1.8
diff -c -3 -p -r1.8 reg-stack.c
*** reg-stack.c	1998/02/13 05:40:28	1.8
--- reg-stack.c	1998/02/24 07:28:42
*************** constrain_asm_operands (n_operands, oper
*** 605,610 ****
--- 605,615 ----
    int n_alternatives;
    int j;
  
+   /* If the ASM has no operands, then it must either be alternative zero
+      or "-1" for no alternative matches.  ??? Which is correct?  */
+   if (n_operands == 0)
+     return 0;
+ 
    for (j = 0; j < n_operands; j++)
      constraints[j] = operand_constraints[j];