re PR middle-end/38505 (Revision 142061 caused ICE on __builtin_memcpy)

	PR middle-end/38505
	* tree-ssa.c (useless_type_conversion_p_1): Return
	false if inner_type is incomplete and outer_type is complete.

	* gcc.c-torture/compile/pr38505.c: New test.

From-SVN: r142806

gcc/ChangeLog

+2008-12-18  Jakub Jelinek  <jakub@redhat.com>
+
+	PR middle-end/38505
+	* tree-ssa.c (useless_type_conversion_p_1): Return
+	false if inner_type is incomplete and outer_type is complete.
+
 2008-12-17  Sebastian Pop  <sebastian.pop@amd.com>
 	
         * doc/install.texi (Prerequisites): Document PPL and CLooG-PPL

gcc/testsuite/ChangeLog

+2008-12-18  Jakub Jelinek  <jakub@redhat.com>
+
+	PR middle-end/38505
+	* gcc.c-torture/compile/pr38505.c: New test.
+
 2008-12-17  Jason Merrill  <jason@redhat.com>
 
 	* g++.dg/cpp0x/auto6.C: Test more stuff.

gcc/testsuite/gcc.c-torture/compile/pr38505.c

+/* PR middle-end/38505 */
+/* { dg-do compile } */
+
+struct S
+{
+  unsigned short a[50];
+  unsigned short b[20];
+};
+extern void bar (struct S *);
+extern void baz (unsigned short *);
+extern unsigned short d[];
+
+void
+foo (void)
+{
+  struct S s;
+  unsigned short g[50];
+
+  baz (g);
+  __builtin_memcpy (&s, g, sizeof (g));
+  __builtin_memcpy (s.b, d, sizeof (s.b));
+  bar (&s);
+}

gcc/tree-ssa.c

@@ -1188,6 +1188,11 @@ useless_type_conversion_p_1 (tree outer_type, tree inner_type)
       if (TREE_CODE (inner_type) != TREE_CODE (outer_type))
 	return false;
 
+      /* Conversion from an incomplete to a complete type is never
+	 useless.  */
+      if (!COMPLETE_TYPE_P (inner_type) && COMPLETE_TYPE_P (outer_type))
+	return false;
+
       /* ???  This seems to be necessary even for aggregates that don't
 	 have TYPE_STRUCTURAL_EQUALITY_P set.  */