misc.c (gnat_type_max_size): Try to return a meaningful value for array types…

misc.c (gnat_type_max_size): Try to return a meaningful value for array types with TYPE_INDEX_TYPE set on...

	* gcc-interface/misc.c (gnat_type_max_size): Try to return a meaningful
	value for array types with TYPE_INDEX_TYPE set on their domain type.
	* gcc-interface/utils.c (max_size): For operations and expressions, do
	not build a new node if the operands have not changed or are missing.

From-SVN: r245698

gcc/ada/gcc-interface/misc.c

@@ -6,7 +6,7 @@
  *                                                                          *
  *                           C Implementation File                          *
  *                                                                          *
- *          Copyright (C) 1992-2016, Free Software Foundation, Inc.         *
+ *          Copyright (C) 1992-2017, Free Software Foundation, Inc.         *
  *                                                                          *
  * GNAT is free software;  you can  redistribute it  and/or modify it under *
  * terms of the  GNU General Public License as published  by the Free Soft- *
@@ -736,22 +736,59 @@ gnat_type_max_size (const_tree gnu_type)
      elaborated and possibly replaced by a VAR_DECL.  */
   tree max_unitsize = max_size (TYPE_SIZE_UNIT (gnu_type), true);
 
-  /* If we don't have a constant, see what we can get from TYPE_ADA_SIZE,
-     which should stay untouched.  */
-  if (!tree_fits_uhwi_p (max_unitsize)
-      && RECORD_OR_UNION_TYPE_P (gnu_type)
-      && !TYPE_FAT_POINTER_P (gnu_type)
-      && TYPE_ADA_SIZE (gnu_type))
+  /* If we don't have a constant, try to look at attributes which should have
+     stayed untouched.  */
+  if (!tree_fits_uhwi_p (max_unitsize))
     {
-      tree max_adasize = max_size (TYPE_ADA_SIZE (gnu_type), true);
-
-      /* If we have succeeded in finding a constant, round it up to the
-	 type's alignment and return the result in units.  */
-      if (tree_fits_uhwi_p (max_adasize))
-	max_unitsize
-	  = size_binop (CEIL_DIV_EXPR,
-			round_up (max_adasize, TYPE_ALIGN (gnu_type)),
-			bitsize_unit_node);
+      /* For record types, see what we can get from TYPE_ADA_SIZE.  */
+      if (RECORD_OR_UNION_TYPE_P (gnu_type)
+	  && !TYPE_FAT_POINTER_P (gnu_type)
+	  && TYPE_ADA_SIZE (gnu_type))
+	{
+	  tree max_adasize = max_size (TYPE_ADA_SIZE (gnu_type), true);
+
+	  /* If we have succeeded in finding a constant, round it up to the
+	     type's alignment and return the result in units.  */
+	  if (tree_fits_uhwi_p (max_adasize))
+	    max_unitsize
+	      = size_binop (CEIL_DIV_EXPR,
+			    round_up (max_adasize, TYPE_ALIGN (gnu_type)),
+			    bitsize_unit_node);
+	}
+
+      /* For array types, see what we can get from TYPE_INDEX_TYPE.  */
+      else if (TREE_CODE (gnu_type) == ARRAY_TYPE
+	       && TYPE_INDEX_TYPE (TYPE_DOMAIN (gnu_type))
+	       && tree_fits_uhwi_p (TYPE_SIZE_UNIT (TREE_TYPE (gnu_type))))
+	{
+	  tree lb = TYPE_MIN_VALUE (TYPE_INDEX_TYPE (TYPE_DOMAIN (gnu_type)));
+	  tree hb = TYPE_MAX_VALUE (TYPE_INDEX_TYPE (TYPE_DOMAIN (gnu_type)));
+	  if (TREE_CODE (lb) != INTEGER_CST
+	      && TYPE_RM_SIZE (TREE_TYPE (lb))
+	      && compare_tree_int (TYPE_RM_SIZE (TREE_TYPE (lb)), 16) <= 0)
+	    lb = TYPE_MIN_VALUE (TREE_TYPE (lb));
+	  if (TREE_CODE (hb) != INTEGER_CST
+	      && TYPE_RM_SIZE (TREE_TYPE (hb))
+	      && compare_tree_int (TYPE_RM_SIZE (TREE_TYPE (hb)), 16) <= 0)
+	    hb = TYPE_MAX_VALUE (TREE_TYPE (hb));
+	  if (TREE_CODE (lb) == INTEGER_CST && TREE_CODE (hb) == INTEGER_CST)
+	    {
+	      tree ctype = get_base_type (TREE_TYPE (lb));
+	      lb = fold_convert (ctype, lb);
+	      hb = fold_convert (ctype, hb);
+	      if (tree_int_cst_le (lb, hb))
+		{
+		  tree length
+		    = fold_build2 (PLUS_EXPR, ctype,
+				   fold_build2 (MINUS_EXPR, ctype, hb, lb),
+				   build_int_cst (ctype, 1));
+		  max_unitsize
+		    = fold_build2 (MULT_EXPR, sizetype,
+				   fold_convert (sizetype, length),
+				   TYPE_SIZE_UNIT (TREE_TYPE (gnu_type)));
+		}
+	    }
+	}
     }
 
   return max_unitsize;

gcc/ada/gcc-interface/utils.c

@@ -3534,6 +3534,7 @@ max_size (tree exp, bool max_p)
 {
   enum tree_code code = TREE_CODE (exp);
   tree type = TREE_TYPE (exp);
+  tree op0, op1, op2;
 
   switch (TREE_CODE_CLASS (code))
     {
@@ -3575,15 +3576,19 @@ max_size (tree exp, bool max_p)
       return exp;
 
     case tcc_comparison:
-      return max_p ? size_one_node : size_zero_node;
+      return build_int_cst (type, max_p ? 1 : 0);
 
     case tcc_unary:
       if (code == NON_LVALUE_EXPR)
 	return max_size (TREE_OPERAND (exp, 0), max_p);
 
-      return fold_build1 (code, type,
-			  max_size (TREE_OPERAND (exp, 0),
-				    code == NEGATE_EXPR ? !max_p : max_p));
+      op0 = max_size (TREE_OPERAND (exp, 0),
+		      code == NEGATE_EXPR ? !max_p : max_p);
+
+      if (op0 == TREE_OPERAND (exp, 0))
+	return exp;
+
+      return fold_build1 (code, type, op0);
 
     case tcc_binary:
       {
@@ -3623,6 +3628,9 @@ max_size (tree exp, bool max_p)
 	    code = PLUS_EXPR;
 	  }
 
+	if (lhs == TREE_OPERAND (exp, 0) && rhs == TREE_OPERAND (exp, 1))
+	  return exp;
+
 	/* We need to detect overflows so we call size_binop here.  */
 	return size_binop (code, lhs, rhs);
       }
@@ -3634,23 +3642,40 @@ max_size (tree exp, bool max_p)
 	  if (code == SAVE_EXPR)
 	    return exp;
 
-	  return fold_build1 (code, type,
-			      max_size (TREE_OPERAND (exp, 0),
-			      code == TRUTH_NOT_EXPR ? !max_p : max_p));
+	  op0 = max_size (TREE_OPERAND (exp, 0),
+			  code == TRUTH_NOT_EXPR ? !max_p : max_p);
+
+	  if (op0 == TREE_OPERAND (exp, 0))
+	    return exp;
+
+	  return fold_build1 (code, type, op0);
 
 	case 2:
 	  if (code == COMPOUND_EXPR)
 	    return max_size (TREE_OPERAND (exp, 1), max_p);
 
-	  return fold_build2 (code, type,
-			      max_size (TREE_OPERAND (exp, 0), max_p),
-			      max_size (TREE_OPERAND (exp, 1), max_p));
+	  op0 = max_size (TREE_OPERAND (exp, 0), max_p);
+	  op1 = max_size (TREE_OPERAND (exp, 1), max_p);
+
+	  if (op0 == TREE_OPERAND (exp, 0) && op1 == TREE_OPERAND (exp, 1))
+	    return exp;
+
+	  return fold_build2 (code, type, op0, op1);
 
 	case 3:
 	  if (code == COND_EXPR)
-	    return fold_build2 (max_p ? MAX_EXPR : MIN_EXPR, type,
-				max_size (TREE_OPERAND (exp, 1), max_p),
-				max_size (TREE_OPERAND (exp, 2), max_p));
+	    {
+	      op1 = TREE_OPERAND (exp, 1);
+	      op2 = TREE_OPERAND (exp, 2);
+
+	      if (!op1 || !op2)
+		return exp;
+
+	      return
+		fold_build2 (max_p ? MAX_EXPR : MIN_EXPR, type,
+			     max_size (op1, max_p), max_size (op2, max_p));
+	    }
+	  break;
 
 	default:
 	  break;