From a55d8232df3dd4f7a3f5b70025074c3919b802a6 Mon Sep 17 00:00:00 2001 From: Richard Sandiford Date: Thu, 14 Nov 2019 15:14:33 +0000 Subject: [PATCH] Avoid retrying with the same vector modes A later patch makes the AArch64 port add four entries to autovectorize_vector_modes. Each entry describes a different vector mode assignment for vector code that mixes 8-bit, 16-bit, 32-bit and 64-bit elements. But if (as usual) the vector code has fewer element sizes than that, we could end up trying the same combination of vector modes multiple times. This patch adds a check to prevent that. 2019-11-14 Richard Sandiford gcc/ * tree-vectorizer.h (vec_info::mode_set): New typedef. (vec_info::used_vector_mode): New member variable. (vect_chooses_same_modes_p): Declare. * tree-vect-stmts.c (get_vectype_for_scalar_type): Record each chosen vector mode in vec_info::used_vector_mode. (vect_chooses_same_modes_p): New function. * tree-vect-loop.c (vect_analyze_loop): Use it to avoid trying the same vector statements multiple times. * tree-vect-slp.c (vect_slp_bb_region): Likewise. From-SVN: r278242 --- gcc/ChangeLog | 12 ++++++++++++ gcc/tree-vect-loop.c | 13 +++++++++++++ gcc/tree-vect-slp.c | 12 ++++++++++++ gcc/tree-vect-stmts.c | 18 ++++++++++++++++++ gcc/tree-vectorizer.h | 5 +++++ 5 files changed, 60 insertions(+) diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 680aa85121a..6b7e9d5477d 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,15 @@ +2019-11-14 Richard Sandiford + + * tree-vectorizer.h (vec_info::mode_set): New typedef. + (vec_info::used_vector_mode): New member variable. + (vect_chooses_same_modes_p): Declare. + * tree-vect-stmts.c (get_vectype_for_scalar_type): Record each + chosen vector mode in vec_info::used_vector_mode. + (vect_chooses_same_modes_p): New function. + * tree-vect-loop.c (vect_analyze_loop): Use it to avoid trying + the same vector statements multiple times. + * tree-vect-slp.c (vect_slp_bb_region): Likewise. + 2019-11-14 Richard Sandiford * machmode.h (opt_machine_mode::operator==): New function. diff --git a/gcc/tree-vect-loop.c b/gcc/tree-vect-loop.c index e60c159d11a..567fcc75e2b 100644 --- a/gcc/tree-vect-loop.c +++ b/gcc/tree-vect-loop.c @@ -2448,6 +2448,19 @@ vect_analyze_loop (class loop *loop, vec_info_shared *shared) } loop->aux = NULL; + + if (!fatal) + while (mode_i < vector_modes.length () + && vect_chooses_same_modes_p (loop_vinfo, vector_modes[mode_i])) + { + if (dump_enabled_p ()) + dump_printf_loc (MSG_NOTE, vect_location, + "***** The result for vector mode %s would" + " be the same\n", + GET_MODE_NAME (vector_modes[mode_i])); + mode_i += 1; + } + if (res) { LOOP_VINFO_VECTORIZABLE_P (loop_vinfo) = 1; diff --git a/gcc/tree-vect-slp.c b/gcc/tree-vect-slp.c index 1e00db5a326..a46bba5ec60 100644 --- a/gcc/tree-vect-slp.c +++ b/gcc/tree-vect-slp.c @@ -3239,6 +3239,18 @@ vect_slp_bb_region (gimple_stmt_iterator region_begin, if (mode_i == 0) autodetected_vector_mode = bb_vinfo->vector_mode; + if (!fatal) + while (mode_i < vector_modes.length () + && vect_chooses_same_modes_p (bb_vinfo, vector_modes[mode_i])) + { + if (dump_enabled_p ()) + dump_printf_loc (MSG_NOTE, vect_location, + "***** The result for vector mode %s would" + " be the same\n", + GET_MODE_NAME (vector_modes[mode_i])); + mode_i += 1; + } + delete bb_vinfo; if (mode_i < vector_modes.length () diff --git a/gcc/tree-vect-stmts.c b/gcc/tree-vect-stmts.c index 36f832bb522..e1fa0756f26 100644 --- a/gcc/tree-vect-stmts.c +++ b/gcc/tree-vect-stmts.c @@ -11263,6 +11263,10 @@ get_vectype_for_scalar_type (vec_info *vinfo, tree scalar_type) scalar_type); if (vectype && vinfo->vector_mode == VOIDmode) vinfo->vector_mode = TYPE_MODE (vectype); + + if (vectype) + vinfo->used_vector_modes.add (TYPE_MODE (vectype)); + return vectype; } @@ -11302,6 +11306,20 @@ get_same_sized_vectype (tree scalar_type, tree vector_type) scalar_type, nunits); } +/* Return true if replacing LOOP_VINFO->vector_mode with VECTOR_MODE + would not change the chosen vector modes. */ + +bool +vect_chooses_same_modes_p (vec_info *vinfo, machine_mode vector_mode) +{ + for (vec_info::mode_set::iterator i = vinfo->used_vector_modes.begin (); + i != vinfo->used_vector_modes.end (); ++i) + if (!VECTOR_MODE_P (*i) + || related_vector_mode (vector_mode, GET_MODE_INNER (*i), 0) != *i) + return false; + return true; +} + /* Function vect_is_simple_use. Input: diff --git a/gcc/tree-vectorizer.h b/gcc/tree-vectorizer.h index fadc4d89d16..b029266f24e 100644 --- a/gcc/tree-vectorizer.h +++ b/gcc/tree-vectorizer.h @@ -298,6 +298,7 @@ public: /* Vectorizer state common between loop and basic-block vectorization. */ class vec_info { public: + typedef hash_set > mode_set; enum vec_kind { bb, loop }; vec_info (vec_kind, void *, vec_info_shared *); @@ -335,6 +336,9 @@ public: /* Cost data used by the target cost model. */ void *target_cost_data; + /* The set of vector modes used in the vectorized region. */ + mode_set used_vector_modes; + /* The argument we should pass to related_vector_mode when looking up the vector mode for a scalar mode, or VOIDmode if we haven't yet made any decisions about which vector modes to use. */ @@ -1630,6 +1634,7 @@ extern tree get_related_vectype_for_scalar_type (machine_mode, tree, extern tree get_vectype_for_scalar_type (vec_info *, tree); extern tree get_mask_type_for_scalar_type (vec_info *, tree); extern tree get_same_sized_vectype (tree, tree); +extern bool vect_chooses_same_modes_p (vec_info *, machine_mode); extern bool vect_get_loop_mask_type (loop_vec_info); extern bool vect_is_simple_use (tree, vec_info *, enum vect_def_type *, stmt_vec_info * = NULL, gimple ** = NULL); -- 2.30.2