rs6000.c (altivec_expand_vec_perm_const): Reverse two operands for little-endian.

2013-07-23  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>
	    Anton Blanchard <anton@au1.ibm.com>

	* config/rs6000/rs6000.c (altivec_expand_vec_perm_const): Reverse
	two operands for little-endian.


Co-Authored-By: Anton Blanchard <anton@au1.ibm.com>

From-SVN: r201195

gcc/ChangeLog

+2013-07-23  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>
+	    Anton Blanchard <anton@au1.ibm.com>
+
+	* config/rs6000/rs6000.c (altivec_expand_vec_perm_const): Reverse
+	two operands for little-endian.
+
 2013-07-23  Steve Ellcey  <sellcey@mips.com>
 
 	* config/mips/mips.c (mips_case_values_threshold): New.

gcc/config/rs6000/rs6000.c

@@ -28520,7 +28520,10 @@ altivec_expand_vec_perm_const (rtx operands[4])
 	  enum machine_mode omode = insn_data[icode].operand[0].mode;
 	  enum machine_mode imode = insn_data[icode].operand[1].mode;
 
-	  if (swapped)
+          /* For little-endian, the two input operands must be swapped
+             (or swapped back) to ensure proper right-to-left numbering
+             from 0 to 2N-1.  */
+	  if (swapped ^ !BYTES_BIG_ENDIAN)
 	    x = op0, op0 = op1, op1 = x;
 	  if (imode != V16QImode)
 	    {