re PR tree-optimization/36291 (GCC is slow and memory-hungry building sipQtGuipart.cpp)

2009-04-08  Richard Guenther  <rguenther@suse.de>

	PR middle-end/36291
	* tree-dfa.c (add_referenced_var): Do not recurse into
	global initializers.
	* tree-ssa-ccp.c (get_symbol_constant_value): Add newly
	exposed variables.
	(fold_const_aggregate_ref): Likewise.

From-SVN: r145757

gcc/ChangeLog

+2009-04-08  Richard Guenther  <rguenther@suse.de>
+
+	PR middle-end/36291
+	* tree-dfa.c (add_referenced_var): Do not recurse into
+	global initializers.
+	* tree-ssa-ccp.c (get_symbol_constant_value): Add newly
+	exposed variables.
+	(fold_const_aggregate_ref): Likewise.
+
 2009-04-08  Paolo Bonzini  <bonzini@gnu.org>
 
         * recog.c (ordered_comparison_operator): New.

gcc/tree-dfa.c

@@ -600,13 +600,11 @@ add_referenced_var (tree var)
     {
       /* Scan DECL_INITIAL for pointer variables as they may contain
 	 address arithmetic referencing the address of other
-	 variables.  
-	 Even non-constant initializers need to be walked, because
-	 IPA passes might prove that their are invariant later on.  */
+	 variables.  As we are only interested in directly referenced
+	 globals or referenced locals restrict this to initializers
+	 than can refer to local variables.  */
       if (DECL_INITIAL (var)
-	  /* Initializers of external variables are not useful to the
-	     optimizers.  */
-          && !DECL_EXTERNAL (var))
+          && DECL_CONTEXT (var) == current_function_decl)
       	walk_tree (&DECL_INITIAL (var), find_vars_r, NULL, 0);
 
       return true;

gcc/tree-ssa-ccp.c

@@ -281,7 +281,15 @@ get_symbol_constant_value (tree sym)
 	{
 	  STRIP_USELESS_TYPE_CONVERSION (val);
 	  if (is_gimple_min_invariant (val))
-	    return val;
+	    {
+	      if (TREE_CODE (val) == ADDR_EXPR)
+		{
+		  tree base = get_base_address (TREE_OPERAND (val, 0));
+		  if (base && TREE_CODE (base) == VAR_DECL)
+		    add_referenced_var (base);
+		}
+	      return val;
+	    }
 	}
       /* Variables declared 'const' without an initializer
 	 have zero as the initializer if they may not be
@@ -1243,6 +1251,12 @@ fold_const_aggregate_ref (tree t)
 	if (tree_int_cst_equal (cfield, idx))
 	  {
 	    STRIP_USELESS_TYPE_CONVERSION (cval);
+	    if (TREE_CODE (cval) == ADDR_EXPR)
+	      {
+		tree base = get_base_address (TREE_OPERAND (cval, 0));
+		if (base && TREE_CODE (base) == VAR_DECL)
+		  add_referenced_var (base);
+	      }
 	    return cval;
 	  }
       break;
@@ -1286,6 +1300,12 @@ fold_const_aggregate_ref (tree t)
 	    && ! DECL_BIT_FIELD (cfield))
 	  {
 	    STRIP_USELESS_TYPE_CONVERSION (cval);
+	    if (TREE_CODE (cval) == ADDR_EXPR)
+	      {
+		tree base = get_base_address (TREE_OPERAND (cval, 0));
+		if (base && TREE_CODE (base) == VAR_DECL)
+		  add_referenced_var (base);
+	      }
 	    return cval;
 	  }
       break;