@@ -640,7 +640,7 @@ extern struct c_expr default_function_ar
struct c_expr);
extern struct c_expr convert_lvalue_to_rvalue (location_t, struct c_expr,
bool, bool);
-extern tree decl_constant_value_1 (tree);
+extern tree decl_constant_value_1 (tree, bool);
extern void mark_exp_read (tree);
extern tree composite_type (tree, tree);
extern tree build_component_ref (location_t, tree, tree, location_t);
@@ -1832,20 +1832,20 @@ c_size_in_bytes (const_tree type)
/* Return either DECL or its known constant value (if it has one). */
tree
-decl_constant_value_1 (tree decl)
+decl_constant_value_1 (tree decl, bool in_init)
{
if (/* Note that DECL_INITIAL isn't valid for a PARM_DECL. */
TREE_CODE (decl) != PARM_DECL
&& !TREE_THIS_VOLATILE (decl)
&& TREE_READONLY (decl)
&& DECL_INITIAL (decl) != NULL_TREE
- && TREE_CODE (DECL_INITIAL (decl)) != ERROR_MARK
+ && !error_operand_p (DECL_INITIAL (decl))
/* This is invalid if initial value is not constant.
If it has either a function call, a memory reference,
or a variable, then re-evaluating it could give different results. */
&& TREE_CONSTANT (DECL_INITIAL (decl))
/* Check for cases where this is sub-optimal, even though valid. */
- && TREE_CODE (DECL_INITIAL (decl)) != CONSTRUCTOR)
+ && (in_init || TREE_CODE (DECL_INITIAL (decl)) != CONSTRUCTOR))
return DECL_INITIAL (decl);
return decl;
}
@@ -1858,7 +1858,7 @@ decl_constant_value (tree decl)
{
/* Don't change a variable array bound or initial value to a constant
in a place where a variable is invalid. */
- return current_function_decl ? decl_constant_value_1 (decl) : decl;
+ return current_function_decl ? decl_constant_value_1 (decl, false) : decl;
}
/* Convert the array expression EXP to a pointer. */
@@ -168,9 +168,15 @@ c_fully_fold_internal (tree expr, bool i
if (VAR_P (expr) && !lval && (optimize || in_init))
{
if (in_init)
- ret = decl_constant_value_1 (expr);
+ ret = decl_constant_value_1 (expr, true);
else
- ret = decl_constant_value (expr);
+ {
+ ret = decl_constant_value (expr);
+ if (ret != expr
+ && (TYPE_MODE (TREE_TYPE (ret)) == BLKmode
+ || TREE_CODE (TREE_TYPE (ret)) == ARRAY_TYPE))
+ return expr;
+ }
/* Avoid unwanted tree sharing between the initializer and current
function's body where the tree can be modified e.g. by the
gimplifier. */
@@ -264,6 +270,8 @@ c_fully_fold_internal (tree expr, bool i
TREE_READONLY (ret) = TREE_READONLY (expr);
TREE_THIS_VOLATILE (ret) = TREE_THIS_VOLATILE (expr);
}
+ if (!lval)
+ ret = fold (ret);
goto out;
case ARRAY_REF:
@@ -0,0 +1,27 @@
+/* PR c/83801 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-original" } */
+
+static const char a[] = "01234567890123456789012345678901234567890123456789012345678901234567890123456789";
+static const char b = a[27];
+struct S { const char c[30]; const char d[30]; };
+static const struct S e[] = { { "01234567890123456789012345678", "90123456789012345678901234567" },
+ { "89012345678901234567890123456", "78901234567890123456789012345" } };
+static const char f = e[1].c[4];
+
+char
+foo (int i)
+{
+ return a[i];
+}
+
+char
+bar (int i)
+{
+ return e[0].d[i];
+}
+
+/* { dg-final { scan-tree-dump {a\[i]} "original" } } */
+/* { dg-final { scan-tree-dump-not {"01234567890123456789012345678901234567890123456789012345678901234567890123456789"\[i]} "original" } } */
+/* { dg-final { scan-tree-dump {e\[0]\.d\[i]} "original" } } */
+/* { dg-final { scan-tree-dump-not {"90123456789012345678901234567"\[i]} "original" } } */