Fix wrong code for indexed component with very large index type

This fixes an old issue whereby we generate wrong code in Ada for an indexed
component in an array with a ludicrously large index type instead of raising
Storage_Error.  We would need the counterpart of int_const_binop for unop in
the general case, but that's not worth the hassle and int_const_convert is
good enough.

gcc/
	PR ada/33994
	* fold-const.h (int_const_convert): New prototype.
	* fold-const.cc (fold_convert_const_int_from_int): Rename to...
	(int_const_convert): ...this, remove static keyword and add third
	parameter OVERFLOWABLE.
	(fold_convert_const): Call int_const_convert if ARG1 is an integer
	constant.

gcc/ada/
	PR ada/33994
	* gcc-interface/utils.cc (convert) <INTEGER_TYPE>: Call
	int_const_convert if the expression is an integer constant.

gcc/testsuite/
	* gnat.dg/object_overflow6.adb: New test.

diff --git a/gcc/ada/gcc-interface/utils.cc b/gcc/ada/gcc-interface/utils.cc
index 83b9e82d2dc89c519e5261e9efcf60be440bcdaf..db736a8d26db79c1010b257e05955284c5549516 100644 (file)
--- a/gcc/ada/gcc-interface/utils.cc
+++ b/gcc/ada/gcc-interface/utils.cc
@@ -5425,6 +5425,11 @@ convert (tree type, tree expr)
            return fold_convert (type, expr);
        }
 
+      if (TREE_CODE (expr) == INTEGER_CST)
+       return int_const_convert (type, expr,
+                                 type == sizetype || type == bitsizetype
+                                 ? -1 : !POINTER_TYPE_P (etype));
+
       /* ... fall through ... */
 
     case ENUMERAL_TYPE:

diff --git a/gcc/fold-const.cc b/gcc/fold-const.cc
index 861d73ce9607a34bec2f65a783a1a34f64bc0180..85e7da595c6a956e48f6e3ef9e598161e2e94296 100644 (file)
--- a/gcc/fold-const.cc
+++ b/gcc/fold-const.cc
@@ -2183,12 +2183,12 @@ size_diffop_loc (location_t loc, tree arg0, tree arg1)
                                                             MINUS_EXPR,
                                                             arg1, arg0)));
 }
-\f
-/* A subroutine of fold_convert_const handling conversions of an
-   INTEGER_CST to another integer type.  */
 
-static tree
-fold_convert_const_int_from_int (tree type, const_tree arg1)
+/* Convert integer constant ARG1 to TYPE, which is an integral or offset
+   or pointer type.  */
+
+tree
+int_const_convert (tree type, const_tree arg1, int overflowable)
 {
   /* Given an integer constant, make new constant with new type,
      appropriately sign-extended or truncated.  Use widest_int
@@ -2197,7 +2197,7 @@ fold_convert_const_int_from_int (tree type, const_tree arg1)
   unsigned prec = MAX (TYPE_PRECISION (arg1_type), TYPE_PRECISION (type));
   return force_fit_type (type, wide_int::from (wi::to_wide (arg1), prec,
                                               TYPE_SIGN (arg1_type)),
-                        !POINTER_TYPE_P (TREE_TYPE (arg1)),
+                        overflowable,
                         TREE_OVERFLOW (arg1));
 }
 
@@ -2500,7 +2500,7 @@ fold_convert_const (enum tree_code code, tree type, tree arg1)
       || TREE_CODE (type) == OFFSET_TYPE)
     {
       if (TREE_CODE (arg1) == INTEGER_CST)
-       return fold_convert_const_int_from_int (type, arg1);
+       return int_const_convert (type, arg1, !POINTER_TYPE_P (arg_type));
       else if (TREE_CODE (arg1) == REAL_CST)
        return fold_convert_const_int_from_real (code, type, arg1);
       else if (TREE_CODE (arg1) == FIXED_CST)

diff --git a/gcc/fold-const.h b/gcc/fold-const.h
index 87e7ec15157a2af9dd8a461ea54468a689909fc2..149992d1f107835f630990e946127e1ec426ba0b 100644 (file)
--- a/gcc/fold-const.h
+++ b/gcc/fold-const.h
@@ -134,6 +134,7 @@ extern bool poly_int_binop (poly_wide_int &res, enum tree_code,
                            const_tree, const_tree, signop,
                            wi::overflow_type *);
 extern tree int_const_binop (enum tree_code, const_tree, const_tree, int = 1);
+extern tree int_const_convert (tree, const_tree, int = 1);
 #define build_fold_addr_expr(T)\
         build_fold_addr_expr_loc (UNKNOWN_LOCATION, (T))
 extern tree build_fold_addr_expr_loc (location_t, tree);

diff --git a/gcc/testsuite/gnat.dg/object_overflow6.adb b/gcc/testsuite/gnat.dg/object_overflow6.adb
new file mode 100644 (file)
index 0000000..8aa8e04
--- /dev/null
+++ b/gcc/testsuite/gnat.dg/object_overflow6.adb
@@ -0,0 +1,15 @@
+-- { dg-do compile }
+
+with System;
+
+procedure Object_Overflow6 is
+
+  type Address is range 0 .. System.Memory_Size;
+
+  type Arr is array (Address) of Character;
+
+  A : Arr; -- { dg-warning "Storage_Error" }
+
+begin
+  A(1) := 'a';
+end;