[AArch64] PR71727 fix -mstrict-align

2017-09-27  Christophe Lyon  <christophe.lyon@linaro.org>

	PR target/71727
	gcc/
	* config/aarch64/aarch64.c
	(aarch64_builtin_support_vector_misalignment): Always return false
	when misalignment is unknown.

	gcc/testsuite/
	* gcc.target/aarch64/pr71727-2.c: New test

From-SVN: r253242

gcc/ChangeLog

+2017-09-27  Christophe Lyon  <christophe.lyon@linaro.org>
+
+	PR target/71727
+	* config/aarch64/aarch64.c
+	(aarch64_builtin_support_vector_misalignment): Always return false
+	when misalignment is unknown.
+
 2017-09-27  Kelvin Nilsen  <kelvin@gcc.gnu.org>
 
 	* config/rs6000/rs6000-p8swap.c (const_load_sequence_p): Revise

gcc/config/aarch64/aarch64.c

@@ -11902,19 +11902,9 @@ aarch64_builtin_support_vector_misalignment (machine_mode mode,
       if (optab_handler (movmisalign_optab, mode) == CODE_FOR_nothing)
         return false;
 
+      /* Misalignment factor is unknown at compile time.  */
       if (misalignment == -1)
-	{
-	  /* Misalignment factor is unknown at compile time but we know
-	     it's word aligned.  */
-	  if (aarch64_simd_vector_alignment_reachable (type, is_packed))
-            {
-              int element_size = TREE_INT_CST_LOW (TYPE_SIZE (type));
-
-              if (element_size != 64)
-                return true;
-            }
-	  return false;
-	}
+	return false;
     }
   return default_builtin_support_vector_misalignment (mode, type, misalignment,
 						      is_packed);

gcc/testsuite/ChangeLog

+2017-09-27  Christophe Lyon  <christophe.lyon@linaro.org>
+
+	PR target/71727
+	* gcc.target/aarch64/pr71727-2.c: New test.
+
 2017-09-27  Kelvin Nilsen  <kelvin@gcc.gnu.org>
 
 	* gcc.target/powerpc/swaps-p8-28.c: New test.