Add a testcase for reload PR 47166

[Richard Sandiford <richard dot sandiford at linaro dot org>]

A reload patch that I posted in January:

    http://gcc.gnu.org/ml/gcc-patches/2011-01/msg00548.html

turned out to be related to PR 47166, so Bernd committed a combined fix:

    http://gcc.gnu.org/ml/gcc-patches/2011-01/msg01620.htmlhttp://gcc.gnu.org/ml/gcc-patches/2011-01/msg01620.html

Is it OK to commit the testcase from the first patch to 4.5 and 4.6?

Thanks,
Richard


gcc/testsuite/
	PR rtl-optimization/47166
	* gcc.c-torture/execute/postmod-1.c: New test.

Index: gcc/testsuite/gcc.c-torture/execute/postmod-1.c
===================================================================
--- /dev/null	2010-12-14 12:47:12.274544604 +0000
+++ gcc/testsuite/gcc.c-torture/execute/postmod-1.c	2011-01-10 13:52:05.000000000 +0000
@@ -0,0 +1,62 @@
+#define DECLARE_ARRAY(A) array##A[0x10]
+#define DECLARE_COUNTER(A) counter##A = 0
+#define DECLARE_POINTER(A) *pointer##A = array##A + x
+/* Create a loop that allows post-modification of pointerA, followed by
+   a use of the post-modified address.  */
+#define BEFORE(A) counter##A += *pointer##A, pointer##A += 3
+#define AFTER(A) counter##A += pointer##A[x]
+
+/* Set up the arrays so that one iteration of the loop sets the counter
+   to 3.0f.  */
+#define INIT_ARRAY(A) array##A[1] = 1.0f, array##A[5] = 2.0f
+
+/* Check that the loop worked correctly for all values.  */
+#define CHECK_ARRAY(A) exit_code |= (counter##A != 3.0f)
+
+/* Having 6 copies triggered the bug for ARM and Thumb.  */
+#define MANY(A) A (0), A (1), A (2), A (3), A (4), A (5)
+
+/* Each addendA should be allocated a register.  */
+#define INIT_VOLATILE(A) addend##A = vol
+#define ADD_VOLATILE(A) vol += addend##A
+
+/* Having 5 copies triggered the bug for ARM and Thumb.  */
+#define MANY2(A) A (0), A (1), A (2), A (3), A (4)
+
+float MANY (DECLARE_ARRAY);
+float MANY (DECLARE_COUNTER);
+
+volatile int stop = 1;
+volatile int vol;
+
+void __attribute__((noinline))
+foo (int x)
+{
+  float MANY (DECLARE_POINTER);
+  int i;
+
+  do
+    {
+      MANY (BEFORE);
+      MANY (AFTER);
+      /* Create an inner loop that should ensure the code above
+	 has registers free for reload inheritance.  */
+      {
+	int MANY2 (INIT_VOLATILE);
+	for (i = 0; i < 10; i++)
+	  MANY2 (ADD_VOLATILE);
+      }
+    }
+  while (!stop);
+}
+
+int
+main (void)
+{
+  int exit_code = 0;
+
+  MANY (INIT_ARRAY);
+  foo (1);
+  MANY (CHECK_ARRAY);
+  return exit_code;
+}