alias.c: (mark_constant_function): Don't check pure functions.

	* alias.c: (mark_constant_function): Don't check pure functions.
	Initialize and end alias analysis.
	(nonlocal_mentioned_p): Rename from nonlocal_reference_p.
	Don't make a special exception for recursion.  Handle
	UNSPEC_VOLATILE.  Don't assume ASM_OPERANDS is non-local
	unless it's volatile.

	* local-alloc.c (equivalence): New structure.
	(reg_equiv): Define.
	(contains_replace_regs): Remove array and use
	field in reg_equiv.
	(memref_referenced_p): Likewise.
	(no_equiv): Likewise.
	(update_equiv_regs): Likewise.

	(equiv_init_varies_p,
	equiv_init_movable_p): New functions.
	(update_equiv_regs): Use them.  Use rtx_varies_p
	instead of function_invariant_p.  Process insns
	from end to beginning.  Allow a REG_EQUIV insn
	within the same loop as a use to be moved, also
	allow it to be moved out of a loop.  Update
	REG_DEAD notes when substituting into an insn.

From-SVN: r36957

gcc/ChangeLog

+Fri Oct 20 00:57:00 EDT 2000  John Wehle  (john@feith.com)
+
+	* alias.c: (mark_constant_function): Don't check pure functions.
+	Initialize and end alias analysis.
+	(nonlocal_mentioned_p): Rename from nonlocal_reference_p.
+	Don't make a special exception for recursion.  Handle
+	UNSPEC_VOLATILE.  Don't assume ASM_OPERANDS is non-local
+	unless it's volatile.
+
+	* local-alloc.c (equivalence): New structure.
+	(reg_equiv): Define.
+	(contains_replace_regs): Remove array and use
+	field in reg_equiv.
+	(memref_referenced_p): Likewise.
+	(no_equiv): Likewise.
+	(update_equiv_regs): Likewise.
+
+	(equiv_init_varies_p,
+	equiv_init_movable_p): New functions.
+	(update_equiv_regs): Use them.  Use rtx_varies_p
+	instead of function_invariant_p.  Process insns
+	from end to beginning.  Allow a REG_EQUIV insn
+	within the same loop as a use to be moved, also
+	allow it to be moved out of a loop.  Update
+	REG_DEAD notes when substituting into an insn.
+
 2000-10-19  Jim Wilson  <wilson@cygnus.com>
 
 	* c-decl.c (start_decl): Check for error_mark_node type before using

gcc/alias.c

@@ -103,7 +103,7 @@ static rtx fixed_scalar_and_varying_struct_p PARAMS ((rtx, rtx, rtx, rtx,
 						      int (*) (rtx)));
 static int aliases_everything_p         PARAMS ((rtx));
 static int write_dependence_p           PARAMS ((rtx, rtx, int));
-static int nonlocal_reference_p         PARAMS ((rtx));
+static int nonlocal_mentioned_p         PARAMS ((rtx));
 
 /* Set up all info needed to perform alias analysis on memory references.  */
 
@@ -1728,11 +1728,11 @@ output_dependence (mem, x)
   return write_dependence_p (mem, x, /*writep=*/1);
 }
 
-/* Returns non-zero if X might refer to something which is not
+/* Returns non-zero if X mentions something which is not
    local to the function and is not constant.  */
 
 static int
-nonlocal_reference_p (x)
+nonlocal_mentioned_p (x)
      rtx x;
 {
   rtx base;
@@ -1792,13 +1792,7 @@ nonlocal_reference_p (x)
       return 1;
 
     case CALL:
-      /* Recursion introduces no additional considerations.  */
-      if (GET_CODE (XEXP (x, 0)) == MEM
-	  && GET_CODE (XEXP (XEXP (x, 0), 0)) == SYMBOL_REF
-	  && strcmp(XSTR (XEXP (XEXP (x, 0), 0), 0),
-		    IDENTIFIER_POINTER (
-			  DECL_ASSEMBLER_NAME (current_function_decl))) == 0)
-	return 0;
+      /* Non-constant calls and recursion are not local.  */
       return 1;
 
     case MEM:
@@ -1829,10 +1823,16 @@ nonlocal_reference_p (x)
 	}
       return 1;
 
+    case UNSPEC_VOLATILE:
     case ASM_INPUT:
-    case ASM_OPERANDS:
       return 1;
 
+    case ASM_OPERANDS:
+      if (MEM_VOLATILE_P (x))
+	return 1;
+
+    /* FALLTHROUGH */
+
     default:
       break;
     }
@@ -1847,14 +1847,14 @@ nonlocal_reference_p (x)
       {
 	if (fmt[i] == 'e' && XEXP (x, i))
 	  {
-	    if (nonlocal_reference_p (XEXP (x, i)))
+	    if (nonlocal_mentioned_p (XEXP (x, i)))
 	      return 1;
 	  }
 	else if (fmt[i] == 'E')
 	  {
 	    register int j;
 	    for (j = 0; j < XVECLEN (x, i); j++)
-	      if (nonlocal_reference_p (XVECEXP (x, i, j)))
+	      if (nonlocal_mentioned_p (XVECEXP (x, i, j)))
 		return 1;
 	  }
       }
@@ -1869,22 +1869,34 @@ void
 mark_constant_function ()
 {
   rtx insn;
+  int nonlocal_mentioned;
 
   if (TREE_PUBLIC (current_function_decl)
       || TREE_READONLY (current_function_decl)
+      || DECL_IS_PURE (current_function_decl)
       || TREE_THIS_VOLATILE (current_function_decl)
       || TYPE_MODE (TREE_TYPE (current_function_decl)) == VOIDmode)
     return;
 
+  nonlocal_mentioned = 0;
+
+  init_alias_analysis ();
+
   /* Determine if this is a constant function.  */
 
   for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
-    if (INSN_P (insn) && nonlocal_reference_p (insn))
-      return;
+    if (INSN_P (insn) && nonlocal_mentioned_p (insn))
+      {
+	nonlocal_mentioned = 1;
+	break;
+      }
+
+  end_alias_analysis ();
 
   /* Mark the function.  */
 
-  TREE_READONLY (current_function_decl) = 1;
+  if (! nonlocal_mentioned)
+    TREE_READONLY (current_function_decl) = 1;
 }