Replace REDUC_*_EXPRs with internal functions.

This patch replaces the REDUC_*_EXPR tree codes with internal functions.
This is needed so that the upcoming in-order reductions can also use
internal functions without too much complication.

2017-11-22  Richard Sandiford  <richard.sandiford@linaro.org>

gcc/
	* tree.def (REDUC_MAX_EXPR, REDUC_MIN_EXPR, REDUC_PLUS_EXPR): Delete.
	* cfgexpand.c (expand_debug_expr): Remove handling for them.
	* expr.c (expand_expr_real_2): Likewise.
	* fold-const.c (const_unop): Likewise.
	* optabs-tree.c (optab_for_tree_code): Likewise.
	* tree-cfg.c (verify_gimple_assign_unary): Likewise.
	* tree-inline.c (estimate_operator_cost): Likewise.
	* tree-pretty-print.c (dump_generic_node): Likewise.
	(op_code_prio): Likewise.
	(op_symbol_code): Likewise.
	* internal-fn.def (DEF_INTERNAL_SIGNED_OPTAB_FN): Define.
	(IFN_REDUC_PLUS, IFN_REDUC_MAX, IFN_REDUC_MIN): New internal functions.
	* internal-fn.c (direct_internal_fn_optab): New function.
	(direct_internal_fn_array, direct_internal_fn_supported_p
	(internal_fn_expanders): Handle DEF_INTERNAL_SIGNED_OPTAB_FN.
	* fold-const-call.c (fold_const_reduction): New function.
	(fold_const_call): Handle CFN_REDUC_PLUS, CFN_REDUC_MAX and
	CFN_REDUC_MIN.
	* tree-vect-loop.c: Include internal-fn.h.
	(reduction_code_for_scalar_code): Rename to...
	(reduction_fn_for_scalar_code): ...this and return an internal
	function.
	(vect_model_reduction_cost): Take an internal_fn rather than
	a tree_code.
	(vect_create_epilog_for_reduction): Likewise.  Build calls rather
	than assignments.
	(vectorizable_reduction): Use internal functions rather than tree
	codes for the reduction operation.  Update calls to the functions
	above.
	* config/aarch64/aarch64-builtins.c (aarch64_gimple_fold_builtin):
	Use calls to internal functions rather than REDUC tree codes.
	* config/aarch64/aarch64-simd.md: Update comment accordingly.

From-SVN: r255073

1 files changed, 28 insertions, 0 deletions

diff --git a/gcc/fold-const-call.c b/gcc/fold-const-call.c
index f23b1bf28bd..4d705980236 100644
--- a/gcc/fold-const-call.c
+++ b/gcc/fold-const-call.c
@@ -583,6 +583,25 @@ fold_const_builtin_nan (tree type, tree arg, bool quiet)
   return NULL_TREE;
 }
 
+/* Fold a call to IFN_REDUC_<CODE> (ARG), returning a value of type TYPE.  */
+
+static tree
+fold_const_reduction (tree type, tree arg, tree_code code)
+{
+  if (TREE_CODE (arg) != VECTOR_CST)
+    return NULL_TREE;
+
+  tree res = VECTOR_CST_ELT (arg, 0);
+  unsigned int nelts = VECTOR_CST_NELTS (arg);
+  for (unsigned int i = 1; i < nelts; i++)
+    {
+      res = const_binop (code, type, res, VECTOR_CST_ELT (arg, i));
+      if (res == NULL_TREE || !CONSTANT_CLASS_P (res))
+	return NULL_TREE;
+    }
+  return res;
+}
+
 /* Try to evaluate:
 
       *RESULT = FN (*ARG)
@@ -1148,6 +1167,15 @@ fold_const_call (combined_fn fn, tree type, tree arg)
     CASE_FLT_FN_FLOATN_NX (CFN_BUILT_IN_NANS):
       return fold_const_builtin_nan (type, arg, false);
 
+    case CFN_REDUC_PLUS:
+      return fold_const_reduction (type, arg, PLUS_EXPR);
+
+    case CFN_REDUC_MAX:
+      return fold_const_reduction (type, arg, MAX_EXPR);
+
+    case CFN_REDUC_MIN:
+      return fold_const_reduction (type, arg, MIN_EXPR);
+
     default:
       return fold_const_call_1 (fn, type, arg);
     }