re PR rtl-optimization/6165 ([i686] stack frame freed too early)

        PR opt/6165
        * alias.c (true_dependence): Force (mem:blk (scratch)) to conflict.
        (write_dependence_p): Likewise.

From-SVN: r51882

gcc/ChangeLog

 2002-04-04  Richard Henderson  <rth@redhat.com>
 
+	PR opt/6165
+	* alias.c (true_dependence): Force (mem:blk (scratch)) to conflict.
+	(write_dependence_p): Likewise.
+
+2002-04-04  Richard Henderson  <rth@redhat.com>
+
 	* predict.c (estimate_bb_frequencies): Do frequency calculation
 	with a volatile temporary.
 

gcc/alias.c

@@ -2039,6 +2039,13 @@ true_dependence (mem, mem_mode, x, varies)
   if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem))
     return 1;
 
+  /* (mem:BLK (scratch)) is a special mechanism to conflict with everything.
+     This is used in epilogue deallocation functions.  */
+  if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH)
+    return 1;
+  if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH)
+    return 1;
+
   if (DIFFERENT_ALIAS_SETS_P (x, mem))
     return 0;
 
@@ -2173,6 +2180,13 @@ write_dependence_p (mem, x, writep)
   if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem))
     return 1;
 
+  /* (mem:BLK (scratch)) is a special mechanism to conflict with everything.
+     This is used in epilogue deallocation functions.  */
+  if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH)
+    return 1;
+  if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH)
+    return 1;
+
   if (DIFFERENT_ALIAS_SETS_P (x, mem))
     return 0;