testcase for 2-2 combine

gcc/testsuite/
	PR rtl-optimization/85160
	* gcc.target/powerpc/combine-2-2.c: New testcase.

From-SVN: r263072

gcc/testsuite/ChangeLog

+2018-07-30  Segher Boessenkool  <segher@kernel.crashing.org>
+
+	PR rtl-optimization/85160
+	* gcc.target/powerpc/combine-2-2.c: New testcase.
+
 2018-07-27  Martin Sebor  <msebor@redhat.com>
 
 	PR tree-optimization/86696

gcc/testsuite/gcc.target/powerpc/combine-2-2.c

+/* { dg-options "-O2" } */
+
+/* PR85160 */
+
+/* Originally, the "x >> 14" are CSEd away (eventually becoming a srawi
+   instruction), and the two ANDs remain separate instructions because
+   combine cannot deal with this.
+
+   Now that combine knows how to combine two RTL insns into two, it manages
+   to make this just the sum of two rlwinm instructions.  */
+
+int f(int x)
+{
+  return ((x >> 14) & 6) + ((x >> 14) & 4);
+}
+
+/* { dg-final { scan-assembler-not {\msrawi\M} } } */