re PR rtl-optimization/33848 (reference to non-existent label at -O1 on mips/mipsel)

gcc/testsuite/
	PR rtl-optimization/33848
	* gcc.dg/torture/pr33848.c: New test.

From-SVN: r130345

gcc/testsuite/ChangeLog

+2007-11-22  Richard Sandiford  <rsandifo@nildram.co.uk>
+
+	PR rtl-optimization/33848
+	* gcc.dg/torture/pr33848.c: New test.
+
 2007-11-21  Francois-Xavier Coudert  <fxcoudert@gcc.gnu.org>
 
 	PR fortran/34083

gcc/testsuite/gcc.dg/torture/pr33848.c

+/* &&foo should be hoisted, but on most targets, excess register pressure
+   forces it to be rematerialized before "data != &&foo".  On targets that
+   have a "branch if registers are equal" instruction, this leads to the
+   branch having two LABEL_REFs: one for the branch target and one for
+   &&foo.  When reloading &&foo into a register, reload would wrongly
+   say that &&foo was the target of the branch, and the real target would
+   then be removed as dead.  */
+/* { dg-do link } */
+#define NVARS 30
+#define MULTI(X) \
+  X( 0), X( 1), X( 2), X( 3), X( 4), X( 5), X( 6), X( 7), X( 8), X( 9), \
+  X(10), X(11), X(12), X(13), X(14), X(15), X(16), X(17), X(18), X(19), \
+  X(20), X(21), X(22), X(23), X(24), X(25), X(26), X(27), X(28), X(29)
+
+#define DECLARE(INDEX) i##INDEX = gv[INDEX]
+#define COPY(INDEX) gv[INDEX] = i##INDEX
+
+volatile int gv[NVARS];
+void *volatile data;
+
+int
+main (void)
+{
+  __label__ foo;
+
+  if (gv[0] == 1)
+    goto foo;
+  data = &&foo;
+  do
+    {
+      int MULTI (DECLARE);
+      MULTI (COPY);
+      MULTI (COPY);
+      MULTI (COPY);
+      if (data != &&foo)
+	gv[0] = 1;
+      else
+	gv[1] = 2;
+    }
+  while (gv[0] > 0);
+ foo:
+  return 0;
+}