2007-10-11  Jakub Jelinek  <jakub@redhat.com>

	PR rtl-optimization/33644
	* dce.c (delete_unmarked_insns): Don't move REG_LIBCALL note
	to an insn without REG_LIBCALL_ID note.

	* gcc.dg/pr33644.c: New test.

--- gcc/dce.c.jj	2007-10-08 10:45:03.000000000 +0200
+++ gcc/dce.c	2007-10-11 20:33:47.000000000 +0200
@@ -278,6 +278,10 @@ delete_unmarked_insns (void)
 		  rtx new_libcall_insn = next_real_insn (insn);
 		  rtx retval_note = find_reg_note (XEXP (note, 0),
 						   REG_RETVAL, NULL_RTX);
+		  while (new_libcall_insn != XEXP (note, 0)
+			 && !find_reg_note (new_libcall_insn, REG_LIBCALL_ID,
+					    NULL_RTX))
+		    new_libcall_insn = next_real_insn (new_libcall_insn);
 		  REG_NOTES (new_libcall_insn)
 		    = gen_rtx_INSN_LIST (REG_LIBCALL, XEXP (note, 0),
 					 REG_NOTES (new_libcall_insn));
--- gcc/testsuite/gcc.dg/pr33644.c.jj	2007-10-11 20:29:20.000000000 +0200
+++ gcc/testsuite/gcc.dg/pr33644.c	2007-10-11 20:13:21.000000000 +0200
@@ -0,0 +1,19 @@
+/* PR rtl-optimization/33644 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -ftrapv" } */
+
+extern char *bar (const char *);
+int *m, *b;
+
+void
+foo (void)
+{
+  int *mv;
+  int p;
+  char a[17];
+
+  p = bar (a) - a;
+  for (mv = m; mv < b; mv++)
+    if (p && ((*mv & 7) != p))
+      *mv = 0;
+}