Introduce gpredict subclass and use it for all gimple_predict_ accessors

gcc/ChangeLog.gimple-classes:
	* coretypes.h (struct gpredict): Add forward declaration.
	* doc/gimple.texi (Class hierarchy of GIMPLE statements): Add
	gpredict.
	* gimple-pretty-print.c (pp_gimple_stmt_1): Within case
	GIMPLE_PREDICT, add local "predict_stmt" via a checked cast and
	use it in place of "stmt".
	* gimple.c (gimple_build_predict): Strengthen return type and
	local "p" from gimple to gpredict *.
	* gimple.h (struct gpredict): New subclass of
	gimple_statement_base, adding invariant that code is
	GIMPLE_PREDICT.
	(is_a_helper <gpredict *>::test): New.
	(gimple_build_predict): Strengthen return type from gimple to
	gpredict *.
	(gimple_predict_predictor): Strengthen param from const_gimple to
	const gpredict *.
	(gimple_predict_outcome): Likewise.
	(gimple_predict_set_predictor): Strengthen param from gimple to
	gpredict *.
	(gimple_predict_set_outcome): Likewise.
	* predict.c (tree_bb_level_predictions): Convert check for
	GIMPLE_PREDICT to a dyn_cast, introducing local "predict_stmt" and
	using it in place of "stmt" for typesafety.

1 files changed, 2 insertions, 2 deletions

diff --git a/gcc/gimple.c b/gcc/gimple.c
index 1421afe1c37..b58c9db800b 100644
--- a/gcc/gimple.c
+++ b/gcc/gimple.c
@@ -1136,10 +1136,10 @@ gimple_build_transaction (gimple_seq body, tree label)
 /* Build a GIMPLE_PREDICT statement.  PREDICT is one of the predictors from
    predict.def, OUTCOME is NOT_TAKEN or TAKEN.  */
 
-gimple
+gpredict *
 gimple_build_predict (enum br_predictor predictor, enum prediction outcome)
 {
-  gimple p = gimple_alloc (GIMPLE_PREDICT, 0);
+  gpredict *p = as_a <gpredict *> (gimple_alloc (GIMPLE_PREDICT, 0));
   /* Ensure all the predictors fit into the lower bits of the subcode.  */
   gcc_assert ((int) END_PREDICTORS <= GF_PREDICT_TAKEN);
   gimple_predict_set_predictor (p, predictor);