diff options
Diffstat (limited to 'gcc/tree-vect-patterns.c')
| -rw-r--r-- | gcc/tree-vect-patterns.c | 46 |
1 files changed, 44 insertions, 2 deletions
diff --git a/gcc/tree-vect-patterns.c b/gcc/tree-vect-patterns.c index 054bfcb..cfae6e0 100644 --- a/gcc/tree-vect-patterns.c +++ b/gcc/tree-vect-patterns.c @@ -148,7 +148,14 @@ widened_name_p (tree name, tree use_stmt, tree *half_type, tree *def_stmt) * Return value: A new stmt that will be used to replace the sequence of stmts that constitute the pattern. In this case it will be: WIDEN_DOT_PRODUCT <x_t, y_t, sum_0> -*/ + + Note: The dot-prod idiom is a widening reduction pattern that is + vectorized without preserving all the intermediate results. It + produces only N/2 (widened) results (by summing up pairs of + intermediate results) rather than all N results. Therefore, we + cannot allow this pattern when we want to get all the results and in + the correct order (as is the case when this computation is in an + inner-loop nested in an outer-loop that us being vectorized). */ static tree vect_recog_dot_prod_pattern (tree last_stmt, tree *type_in, tree *type_out) @@ -160,6 +167,8 @@ vect_recog_dot_prod_pattern (tree last_stmt, tree *type_in, tree *type_out) tree type, half_type; tree pattern_expr; tree prod_type; + loop_vec_info loop_info = STMT_VINFO_LOOP_VINFO (stmt_vinfo); + struct loop *loop = LOOP_VINFO_LOOP (loop_info); if (TREE_CODE (last_stmt) != GIMPLE_MODIFY_STMT) return NULL; @@ -242,6 +251,10 @@ vect_recog_dot_prod_pattern (tree last_stmt, tree *type_in, tree *type_out) gcc_assert (stmt_vinfo); if (STMT_VINFO_DEF_TYPE (stmt_vinfo) != vect_loop_def) return NULL; + /* FORNOW. Can continue analyzing the def-use chain when this stmt in a phi + inside the loop (in case we are analyzing an outer-loop). */ + if (TREE_CODE (stmt) != GIMPLE_MODIFY_STMT) + return NULL; expr = GIMPLE_STMT_OPERAND (stmt, 1); if (TREE_CODE (expr) != MULT_EXPR) return NULL; @@ -295,6 +308,16 @@ vect_recog_dot_prod_pattern (tree last_stmt, tree *type_in, tree *type_out) fprintf (vect_dump, "vect_recog_dot_prod_pattern: detected: "); print_generic_expr (vect_dump, pattern_expr, TDF_SLIM); } + + /* We don't allow changing the order of the computation in the inner-loop + when doing outer-loop vectorization. */ + if (nested_in_vect_loop_p (loop, last_stmt)) + { + if (vect_print_dump_info (REPORT_DETAILS)) + fprintf (vect_dump, "vect_recog_dot_prod_pattern: not allowed."); + return NULL; + } + return pattern_expr; } @@ -521,7 +544,14 @@ vect_recog_pow_pattern (tree last_stmt, tree *type_in, tree *type_out) * Return value: A new stmt that will be used to replace the sequence of stmts that constitute the pattern. In this case it will be: WIDEN_SUM <x_t, sum_0> -*/ + + Note: The widneing-sum idiom is a widening reduction pattern that is + vectorized without preserving all the intermediate results. It + produces only N/2 (widened) results (by summing up pairs of + intermediate results) rather than all N results. Therefore, we + cannot allow this pattern when we want to get all the results and in + the correct order (as is the case when this computation is in an + inner-loop nested in an outer-loop that us being vectorized). */ static tree vect_recog_widen_sum_pattern (tree last_stmt, tree *type_in, tree *type_out) @@ -531,6 +561,8 @@ vect_recog_widen_sum_pattern (tree last_stmt, tree *type_in, tree *type_out) stmt_vec_info stmt_vinfo = vinfo_for_stmt (last_stmt); tree type, half_type; tree pattern_expr; + loop_vec_info loop_info = STMT_VINFO_LOOP_VINFO (stmt_vinfo); + struct loop *loop = LOOP_VINFO_LOOP (loop_info); if (TREE_CODE (last_stmt) != GIMPLE_MODIFY_STMT) return NULL; @@ -580,6 +612,16 @@ vect_recog_widen_sum_pattern (tree last_stmt, tree *type_in, tree *type_out) fprintf (vect_dump, "vect_recog_widen_sum_pattern: detected: "); print_generic_expr (vect_dump, pattern_expr, TDF_SLIM); } + + /* We don't allow changing the order of the computation in the inner-loop + when doing outer-loop vectorization. */ + if (nested_in_vect_loop_p (loop, last_stmt)) + { + if (vect_print_dump_info (REPORT_DETAILS)) + fprintf (vect_dump, "vect_recog_widen_sum_pattern: not allowed."); + return NULL; + } + return pattern_expr; } |