[RS6000] Rotate testcase

The testcase exercises one of the rotate patterns.

gcc/
	* config/rs6000/predicates.md (logical_const_operand),
	(logical_operand): Correct comment.
gcc/testsuite/
	* gcc.target/powerpc/rotmask.c: New.

From-SVN: r266046

gcc/ChangeLog

 2018-11-13  Alan Modra  <amodra@gmail.com>
 
+	* config/rs6000/predicates.md (logical_const_operand),
+	(logical_operand): Correct comment.
+
+2018-11-13  Alan Modra  <amodra@gmail.com>
+
 	* config/rs6000/rs6000.md (addsi3_high): Prefix with '*'.
 
 2018-11-13  Alan Modra  <amodra@gmail.com>

gcc/config/rs6000/predicates.md

@@ -922,7 +922,7 @@
 		    && !satisfies_constraint_L (op)")))
 
 ;; Return 1 if the operand is a constant that can be used as the operand
-;; of an OR or XOR.
+;; of an AND, OR or XOR.
 (define_predicate "logical_const_operand"
   (match_code "const_int")
 {
@@ -935,7 +935,7 @@
 })
 
 ;; Return 1 if the operand is a non-special register or a constant that
-;; can be used as the operand of an OR or XOR.
+;; can be used as the operand of an AND, OR or XOR.
 (define_predicate "logical_operand"
   (ior (match_operand 0 "gpc_reg_operand")
        (match_operand 0 "logical_const_operand")))

gcc/testsuite/ChangeLog

+2018-11-13  Alan Modra  <amodra@gmail.com>
+
+	* gcc.target/powerpc/rotmask.c: New.
+
 2018-11-13  Kugan Vivekanandarajah  <kuganv@linaro.org>
 
 	PR middle-end/86677

gcc/testsuite/gcc.target/powerpc/rotmask.c

+/* { dg-require-effective-target lp64 } */
+/* { dg-options "-O2" } */
+/* { dg-final { scan-assembler-not "rotldi" } } */
+
+unsigned long f (unsigned long x)
+{
+  return ((x << 1) | (x >> 63)) & 0xffffffff;
+}