Add testcase for PR20742.

2010-07-20  Sebastian Pop  <sebastian.pop@amd.com>

	* gcc.dg/tree-ssa/pr20742.c: New.

From-SVN: r163150

gcc/ChangeLog.graphite

+2010-07-20  Sebastian Pop  <sebastian.pop@amd.com>
+
+	* gcc.dg/tree-ssa/pr20742.c: New.
+
 2010-07-15  Sebastian Pop  <sebastian.pop@amd.com>
 
 	* sese.c (rename_uses): Call unshare_expr before force_gimple_operand.

gcc/testsuite/ChangeLog

 2010-08-02  Sebastian Pop  <sebastian.pop@amd.com>
 
+	* gcc.dg/tree-ssa/pr20742.c: New.
+
+2010-08-02  Sebastian Pop  <sebastian.pop@amd.com>
+
 	* gcc.dg/graphite/id-23.c: New.
 
 2010-08-02  Sebastian Pop  <sebastian.pop@amd.com>

gcc/testsuite/gcc.dg/tree-ssa/pr20742.c

+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+#define TEN(x) x x x x x x x x x x
+#define THOUSAND(x) TEN (TEN (TEN (x)))
+
+int
+foo (int x, int y)
+{
+  register int a = y + 57;
+  register int b = y + 31;
+
+  while (x-- > 0)
+    {
+      THOUSAND (a += b; b -= a;)
+    }
+  return a + b;
+}