Fix wrong code by arm_final_prescan with fp16 move instructions

ChangeLog entry are as follow:

*** gcc/ChangeLog ***

2017-12-01  Sudakshina Das  <sudi.das@arm.com>

	* config/arm/vfp.md (*movhf_vfp_fp16): Add conds attribute.

*** gcc/testsuite/ChangeLog ***

2017-12-01  Sudakshina Das  <sudi.das@arm.com>

	* gcc.target/arm/armv8_2-fp16-move-2.c: New test.

From-SVN: r255301

gcc/ChangeLog

+2017-12-01  Sudakshina Das  <sudi.das@arm.com>
+
+	* config/arm/vfp.md (*movhf_vfp_fp16): Add conds attribute.
+
 2017-12-01  Jakub Jelinek  <jakub@redhat.com>
 
 	* function.h (struct function): Remove cilk_frame_decl,

gcc/config/arm/vfp.md

@@ -410,7 +410,10 @@
       gcc_unreachable ();
     }
  }
-  [(set_attr "predicable" "yes, yes, no, yes, no, no, no, no, no, no")
+  [(set_attr "conds" "*, *, unconditional, *, unconditional, unconditional,\
+		      unconditional, unconditional, unconditional,\
+		      unconditional")
+   (set_attr "predicable" "yes, yes, no, yes, no, no, no, no, no, no")
    (set_attr "predicable_short_it" "no, no, no, yes,\
 				    no, no, no, no,\
 				    no, no")

gcc/testsuite/ChangeLog

+2017-12-01  Sudakshina Das  <sudi.das@arm.com>
+
+	* gcc.target/arm/armv8_2-fp16-move-2.c: New test.
+
 2017-12-01  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c/79153

gcc/testsuite/gcc.target/arm/armv8_2-fp16-move-2.c

+/* { dg-do compile }  */
+/* { dg-require-effective-target arm_v8_2a_fp16_scalar_ok }  */
+/* { dg-options "-O2 -marm" }  */
+/* { dg-add-options arm_v8_2a_fp16_scalar }  */
+
+__fp16
+test_select (__fp16 a, __fp16 b, __fp16 c)
+{
+  return (a < b) ? b : c;
+}
+/* { dg-final { scan-assembler "bmi" } } */