re PR middle-end/23155 (Gimplification failed for union cast)

2005-11-03  Andrew Pinski  <pinskia@physics.uc.edu>

        PR middle-end/23155
        * g++.dg/ext/c99struct1.C: New test.
        * gcc.dg/union-cast-1.c: New test.
        * gcc.dg/union-cast-2.c: New test.
        * gcc.dg/union-cast-3.c: New test.

2005-11-03  Andrew Pinski  <pinskia@physics.uc.edu>

        PR middle-end/23155
        * gimplifier.c (gimplify_expr): Create a temporary for lvalue
        CONSTRUCTOR.

From-SVN: r106438

gcc/ChangeLog

+2005-11-03  Andrew Pinski  <pinskia@physics.uc.edu>
+
+	PR middle-end/23155
+	* gimplifier.c (gimplify_expr): Create a temporary for lvalue
+	CONSTRUCTOR.
+
 2005-11-03  Daniel Berlin  <dberlin@dberlin.org>
 
 	Fix PR tree-optimization/24351

gcc/gimplify.c

@@ -4323,6 +4323,15 @@ gimplify_expr (tree *expr_p, tree *pre_p, tree *post_p,
 	      *expr_p = temp;
 	      ret = GS_OK;
 	    }
+	  /* C99 code may assign to an array in a constructed
+	     structure or union, and this has undefined behavior only
+	     on execution, so create a temporary if an lvalue is
+	     required.  */
+	  else if (fallback == fb_lvalue)
+	    {
+	      *expr_p = get_initialized_tmp_var (*expr_p, pre_p, post_p);
+	      lang_hooks.mark_addressable (*expr_p);
+	    }
 	  else
 	    ret = GS_ALL_DONE;
 	  break;

gcc/testsuite/ChangeLog

 2005-11-03  Andrew Pinski  <pinskia@physics.uc.edu>
 
+	PR middle-end/23155 
+	* g++.dg/ext/c99struct1.C: New test.
+	* gcc.dg/union-cast-1.c: New test.
+	* gcc.dg/union-cast-2.c: New test.
+	* gcc.dg/union-cast-3.c: New test.
+
+2005-11-03  Andrew Pinski  <pinskia@physics.uc.edu>
+
 	PR middle-end/24589
 	* gcc.c-torture/execute/zero-struct-2.c: New test.
 

gcc/testsuite/g++.dg/ext/c99struct1.C

+// { dg-options "" }
+// C99 anon struct variable with array accesses.
+
+struct s { int a[1]; };
+
+void
+foo5 (void)
+{
+	  ((struct s) { { 0 } }).a[0] = 1;
+}
+
+

gcc/testsuite/gcc.dg/union-cast-1.c

+/* { dg-do compile } */
+/* { dg-options "-std=gnu89" } */
+/* A combine of two extensions to C89 are used here.
+   First casts to unions is used.
+   Second subscripting non lvalue arrays, this is in C99. */
+
+union vx {short f[8]; int v;};
+int vec;
+
+void
+foo5 (int vec)
+{
+  ((union vx) vec).f[5] = 1;
+}

gcc/testsuite/gcc.dg/union-cast-2.c

+/* { dg-do compile } */
+/* { dg-options "-std=c89 -pedantic-errors" } */
+/* PR 23155
+   We should get two error messages, one about union cast
+   and the other about array access for non lvalues.  */
+
+
+union vx {short f[8]; int v;};
+int vec;
+
+void
+foo5 (int vec)
+{
+  ((union vx) vec).f[5] = 1; /* { dg-error "(forbids subscripting)|(forbids casts to union type)" } */
+}

gcc/testsuite/gcc.dg/union-cast-3.c

+/* { dg-do compile } */
+/* { dg-options "-std=c99 -pedantic-errors" } */
+/* PR 23155
+   We should get one error messag, one about union cast. */
+
+
+union vx {short f[8]; int v;};
+int vec;
+
+void
+foo5 (int vec)
+{
+  ((union vx) vec).f[5] = 1; /* { dg-error "forbids casts to union type" } */
+}