re PR sanitizer/56990 (ICE: SIGFPE with -fsanitize=thread and empty struct)

	PR sanitizer/56990
	* tsan.c (instrument_expr): Don't instrument expression
	in case its size is zero.

	* gcc.dg/pr56990.c: New test.

From-SVN: r198147

gcc/ChangeLog

+2013-04-22  Marek Polacek  <polacek@redhat.com>
+
+	PR sanitizer/56990
+	* tsan.c (instrument_expr): Don't instrument expression
+	in case its size is zero.
+
 2013-04-22  Uros Bizjak  <ubizjak@gmail.com>
 
 	PR target/57032

gcc/testsuite/ChangeLog

+2013-04-22  Marek Polacek  <polacek@redhat.com>
+
+	PR sanitizer/56990
+	* gcc.dg/pr56990.c: New test.
+
 2013-04-22  Vladimir Makarov  <vmakarov@redhat.com>
 
 	PR target/57018

gcc/testsuite/gcc.dg/pr56990.c

+/* PR sanitizer/56990 */
+/* { dg-do compile { target { x86_64-*-linux* && lp64 } } } */
+/* { dg-options "-fsanitize=thread" } */
+
+struct S{};
+
+void foo(struct S *p)
+{
+  *p = (struct S){};
+}

gcc/tsan.c

@@ -131,7 +131,8 @@ instrument_expr (gimple_stmt_iterator gsi, tree expr, bool is_write)
   if (TREE_READONLY (base))
     return false;
 
-  if (bitpos % (size * BITS_PER_UNIT)
+  if (size == 0
+      || bitpos % (size * BITS_PER_UNIT)
       || bitsize != size * BITS_PER_UNIT)
     return false;