re PR rtl-optimization/35729 (const volatile variable access incorrectly hoisted out of loop)

	PR rtl-optimization/35729
	* loop-invariant.c (check_maybe_invariant): Disallow volatile memory
	references.

	* gcc.dg/pr35729.c: New test.

From-SVN: r133755

gcc/ChangeLog

+2008-03-31  Zdenek Dvorak  <ook@ucw.cz>
+
+	PR rtl-optimization/35729
+	* loop-invariant.c (check_maybe_invariant): Disallow volatile memory
+	references.
+
 2008-03-31  H.J. Lu  <hongjiu.lu@intel.com>
 
 	PR target/32000

gcc/loop-invariant.c

@@ -206,7 +206,7 @@ check_maybe_invariant (rtx x)
 
       /* Just handle the most trivial case where we load from an unchanging
 	 location (most importantly, pic tables).  */
-      if (MEM_READONLY_P (x))
+      if (MEM_READONLY_P (x) && !MEM_VOLATILE_P (x))
 	break;
 
       return false;

gcc/testsuite/ChangeLog

+2008-03-31  Zdenek Dvorak  <ook@ucw.cz>
+
+	PR rtl-optimization/35729
+	* gcc.dg/pr35729.c: New test.
+
 2008-03-31  H.J. Lu  <hongjiu.lu@intel.com>
 
 	PR target/32000

gcc/testsuite/gcc.dg/pr35729.c

+/* { dg-do compile } */
+/* { dg-options "-Os -fdump-rtl-loop2_invariant" } */
+
+const volatile int g_361 = 3L;
+volatile int g_2 = 0L;
+void func_1 (void)
+{
+  for (g_2 = 0; g_2 > 10; g_2++)
+    {
+      int l_357 = g_361;
+    }
+}
+
+/* { dg-final { scan-rtl-dump-times "Decided to move invariant" 0 "loop2_invariant" } } */
+/* { dg-final { cleanup-rtl-dump "loop2_invariant" } } */