re PR c/17855 (modification of function struct return not diagnosed)

	PR c/17855
	* gimplify.c (gimplify_expr): Create a temporary for lvalue
	COND_EXPR and CALL_EXPR.

testsuite:
	* gcc.c-torture/compile/struct-non-lval-1.c,
	gcc.c-torture/compile/struct-non-lval-2.c,
	gcc.c-torture/compile/struct-non-lval-3.c: New tests.

From-SVN: r97352

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 9b9ff0d25ce306e9540a7a271974bcf027c54644..fac7f920737754ab26f59ee2abdf2bcdde6193d7 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2005-04-01  Joseph S. Myers  <joseph@codesourcery.com>
+
+       PR c/17855
+       * gimplify.c (gimplify_expr): Create a temporary for lvalue
+       COND_EXPR and CALL_EXPR.
+
 2005-03-31  Vladimir Makarov  <vmakarov@redhat.com>
 
        PR target/20632

diff --git a/gcc/gimplify.c b/gcc/gimplify.c
index 9191baea26a8f19280d32df8be4fef25970bc654..bd15e045a1653c4a2ce0a78e91f1db55747e03ac 100644 (file)
--- a/gcc/gimplify.c
+++ b/gcc/gimplify.c
@@ -3810,10 +3810,28 @@ gimplify_expr (tree *expr_p, tree *pre_p, tree *post_p,
        case COND_EXPR:
          ret = gimplify_cond_expr (expr_p, pre_p, post_p, NULL_TREE,
                                    fallback);
+         /* C99 code may assign to an array in a structure value of a
+            conditional expression, and this has undefined behavior
+            only on execution, so create a temporary if an lvalue is
+            required.  */
+         if (fallback == fb_lvalue)
+           {
+             *expr_p = get_initialized_tmp_var (*expr_p, pre_p, post_p);
+             lang_hooks.mark_addressable (*expr_p);
+           }
          break;
 
        case CALL_EXPR:
          ret = gimplify_call_expr (expr_p, pre_p, fallback != fb_none);
+         /* C99 code may assign to an array in a structure returned
+            from a function, and this has undefined behavior only on
+            execution, so create a temporary if an lvalue is
+            required.  */
+         if (fallback == fb_lvalue)
+           {
+             *expr_p = get_initialized_tmp_var (*expr_p, pre_p, post_p);
+             lang_hooks.mark_addressable (*expr_p);
+           }
          break;
 
        case TREE_LIST:

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 6e6601dfe651d90b0f91aa1c43b55c53379c742d..f3c2617691581a281f5021daef8f8db8cd13e0f3 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,10 @@
+2005-04-01  Joseph S. Myers  <joseph@codesourcery.com>
+
+       PR c/17855
+       * gcc.c-torture/compile/struct-non-lval-1.c,
+       gcc.c-torture/compile/struct-non-lval-2.c,
+       gcc.c-torture/compile/struct-non-lval-3.c: New tests.
+
 2005-03-31  Janis Johnson  <janis187@us.ibm.com>
 
        * gcc.dg/tls/tls.exp: Remove temporary file.

diff --git a/gcc/testsuite/gcc.c-torture/compile/struct-non-lval-1.c b/gcc/testsuite/gcc.c-torture/compile/struct-non-lval-1.c
new file mode 100644 (file)
index 0000000..0924f5c
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/compile/struct-non-lval-1.c
@@ -0,0 +1,7 @@
+/* Bug c/17855.  */
+struct foo {char x, y, z[2];};
+struct foo f();
+void bar(int baz)
+{
+  f().z[baz] = 1;
+}

diff --git a/gcc/testsuite/gcc.c-torture/compile/struct-non-lval-2.c b/gcc/testsuite/gcc.c-torture/compile/struct-non-lval-2.c
new file mode 100644 (file)
index 0000000..daa0d17
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/compile/struct-non-lval-2.c
@@ -0,0 +1,7 @@
+/* Bug c/17855, using conditional expression for non-lvalue.  */
+struct foo {char x, y, z[2];};
+struct foo p, q; int r;
+void bar(int baz)
+{
+  (r ? p : q).z[baz] = 1;
+}

diff --git a/gcc/testsuite/gcc.c-torture/compile/struct-non-lval-3.c b/gcc/testsuite/gcc.c-torture/compile/struct-non-lval-3.c
new file mode 100644 (file)
index 0000000..3020194
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/compile/struct-non-lval-3.c
@@ -0,0 +1,7 @@
+/* Bug c/17855, using assignment for non-lvalue.  */
+struct foo {char x, y, z[2];};
+struct foo p, q;
+void bar(int baz)
+{
+  (p = q).z[baz] = 1;
+}