Fix fallthrough attribute ignorance w/ -fsanitize=address (PR sanitizer/82792).

2017-11-08  Martin Liska  <mliska@suse.cz>

	PR sanitizer/82792
	* gimplify.c (expand_FALLTHROUGH_r): Skip IFN_ASAN_MARK.
2017-11-08  Martin Liska  <mliska@suse.cz>

	PR sanitizer/82792
	* g++.dg/asan/pr82792.C: New test.

From-SVN: r254519

gcc/ChangeLog

+2017-11-08  Martin Liska  <mliska@suse.cz>
+
+	PR sanitizer/82792
+	* gimplify.c (expand_FALLTHROUGH_r): Skip IFN_ASAN_MARK.
+
 2017-11-07  Eric Botcazou  <ebotcazou@adacore.com>
 
 	* gimple-pretty-print.c (dump_profile): Return "" instead of NULL.

gcc/gimplify.c

@@ -2223,7 +2223,8 @@ expand_FALLTHROUGH_r (gimple_stmt_iterator *gsi_p, bool *handled_ops_p,
 	  while (!gsi_end_p (gsi2))
 	    {
 	      stmt = gsi_stmt (gsi2);
-	      if (gimple_code (stmt) == GIMPLE_LABEL)
+	      enum gimple_code gc = gimple_code (stmt);
+	      if (gc == GIMPLE_LABEL)
 		{
 		  tree label = gimple_label_label (as_a <glabel *> (stmt));
 		  if (gimple_has_location (stmt) && DECL_ARTIFICIAL (label))
@@ -2232,8 +2233,11 @@ expand_FALLTHROUGH_r (gimple_stmt_iterator *gsi_p, bool *handled_ops_p,
 		      break;
 		    }
 		}
+	      else if (gc == GIMPLE_CALL
+		       && gimple_call_internal_p (stmt, IFN_ASAN_MARK))
+		;
 	      else
-		/* Something other than a label.  That's not expected.  */
+		/* Something other is not expected.  */
 		break;
 	      gsi_next (&gsi2);
 	    }

gcc/testsuite/ChangeLog

+2017-11-08  Martin Liska  <mliska@suse.cz>
+
+	PR sanitizer/82792
+	* g++.dg/asan/pr82792.C: New test.
+
 2017-11-07  Jakub Jelinek  <jakub@redhat.com>
 
 	PR target/82855

gcc/testsuite/g++.dg/asan/pr82792.C

+/* PR sanitizer/82792 */
+/* { dg-do compile } */
+/* { dg-options "-fsanitize=address" } */
+
+extern int
+test (int i, int j)
+{
+  long c;
+  (c) = 1;
+  switch (i)
+    {
+    case 1:
+      if (j)
+	{
+	  c = 1;
+	}
+      goto default_case;
+    case 2:
+      {
+	if (j)
+	  {
+	    c = 0;
+	  }
+      }
+      __attribute ((fallthrough));
+    default_case:
+    default:
+      c = 0;
+      break;
+    }
+  return 0;
+}