SPARC: Make sure that jump is to a label in errata workaround

In some cases the jump could be to a return instruction and in those cases the
next_active_insn() function tries to follow an invalid pointer which leads to a
crash. This error did not manifest when using a 32-bit version of GCC which is
why I did not detect it before.

gcc/
	* config/sparc/sparc.c (sparc_do_work_around_errata): Make sure
	the jump is to a label.

From-SVN: r255807

gcc/ChangeLog

+2017-12-19  Daniel Cederman  <cederman@gaisler.com>
+
+	* config/sparc/sparc.c (sparc_do_work_around_errata): Make sure
+	the jump is to a label.
+
 2017-12-19  Jakub Jelinek  <jakub@redhat.com>
 
 	PR tree-optimization/83444

gcc/config/sparc/sparc.c

@@ -1066,6 +1066,7 @@ sparc_do_work_around_errata (void)
 	 floating-point operation or a floating-point branch.  */
       if (sparc_fix_gr712rc
 	  && jump
+	  && jump_to_label_p (jump)
 	  && get_attr_branch_type (jump) == BRANCH_TYPE_ICC)
 	{
 	  rtx_insn *target = next_active_insn (JUMP_LABEL_AS_INSN (jump));
@@ -1085,7 +1086,7 @@ sparc_do_work_around_errata (void)
 	  && mem_ref (SET_SRC (set))
 	  && REG_P (SET_DEST (set)))
 	{
-	  if (jump)
+	  if (jump && jump_to_label_p (jump))
 	    {
 	      rtx_insn *target = next_active_insn (JUMP_LABEL_AS_INSN (jump));
 	      if (target && atomic_insn_for_leon3_p (target))