[Vectorizer] Make REDUC_xxx_EXPR tree codes produce a scalar result

	PR tree-optimization/61114
	* expr.c (expand_expr_real_2): For REDUC_{MIN,MAX,PLUS}_EXPR, add
	extract_bit_field around optab result.

	* fold-const.c (fold_unary_loc): For REDUC_{MIN,MAX,PLUS}_EXPR, produce
	scalar not vector.

	* tree-cfg.c (verify_gimple_assign_unary): Check result vs operand type
	for REDUC_{MIN,MAX,PLUS}_EXPR.

	* tree-vect-loop.c (vect_analyze_loop): Update comment.
	(vect_create_epilog_for_reduction): For direct vector reduction, use
	result of tree code directly without extract_bit_field.

	* tree.def (REDUC_MAX_EXPR, REDUC_MIN_EXPR, REDUC_PLUS_EXPR): Update
	comment.

From-SVN: r216736

1 files changed, 11 insertions, 1 deletions

diff --git a/gcc/expr.c b/gcc/expr.c
index 81c9219..e9cabbe 100644
--- a/gcc/expr.c
+++ b/gcc/expr.c
@@ -9051,7 +9051,17 @@ expand_expr_real_2 (sepops ops, rtx target, enum machine_mode tmode,
       {
         op0 = expand_normal (treeop0);
         this_optab = optab_for_tree_code (code, type, optab_default);
-        temp = expand_unop (mode, this_optab, op0, target, unsignedp);
+        enum machine_mode vec_mode = TYPE_MODE (TREE_TYPE (treeop0));
+        temp = expand_unop (vec_mode, this_optab, op0, NULL_RTX, unsignedp);
+        gcc_assert (temp);
+        /* The tree code produces a scalar result, but (somewhat by convention)
+           the optab produces a vector with the result in element 0 if
+           little-endian, or element N-1 if big-endian.  So pull the scalar
+           result out of that element.  */
+        int index = BYTES_BIG_ENDIAN ? GET_MODE_NUNITS (vec_mode) - 1 : 0;
+        int bitsize = GET_MODE_BITSIZE (GET_MODE_INNER (vec_mode));
+        temp = extract_bit_field (temp, bitsize, bitsize * index, unsignedp,
+				  target, mode, mode);
         gcc_assert (temp);
         return temp;
       }