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tree-optimization/100089 - avoid leaving scalar if-converted code around

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This avoids leaving scalar if-converted code around for the case
of BB vectorizing an if-converted loop body when using the very-cheap
cost model.  In this case we scan not vectorized scalar stmts in
the basic-block vectorized for COND_EXPRs and force the vectorization
to be marked as not profitable.

The patch also makes sure to always consider all BB vectorization
subgraphs together for costing purposes when vectorizing an
if-converted loop body.

2021-08-24  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/100089
	* tree-vectorizer.h (vect_slp_bb): Rename to ...
	(vect_slp_if_converted_bb): ... this and get the original
	loop as new argument.
	* tree-vectorizer.c (try_vectorize_loop_1): Revert previous fix,
	pass original loop to vect_slp_if_converted_bb.
	* tree-vect-slp.c (vect_bb_vectorization_profitable_p):
	If orig_loop was passed scan the not vectorized stmts
	for COND_EXPRs and force not profitable if found.
	(vect_slp_region): Pass down all SLP instances to costing
	if orig_loop was specified.
	(vect_slp_bbs): Pass through orig_loop.
	(vect_slp_bb): Rename to ...
	(vect_slp_if_converted_bb): ... this and get the original
	loop as new argument.
	(vect_slp_function): Adjust.
This commit is contained in:
Richard Biener 2021-08-24 12:25:25 +02:00
parent 809330ab84
commit 9216ee6d11
3 changed files with 68 additions and 24 deletions
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70
gcc/tree-vect-slp.c
View File

@ -5233,7 +5233,8 @@ li_cost_vec_cmp (const void *a_, const void *b_)
static bool
vect_bb_vectorization_profitable_p (bb_vec_info bb_vinfo,
vec<slp_instance> slp_instances)
vec<slp_instance> slp_instances,
loop_p orig_loop)
{
slp_instance instance;
int i;
@ -5270,6 +5271,30 @@ vect_bb_vectorization_profitable_p (bb_vec_info bb_vinfo,
vector_costs.safe_splice (instance->cost_vec);
instance->cost_vec.release ();
}
/* When we're vectorizing an if-converted loop body with the
very-cheap cost model make sure we vectorized all if-converted
code. */
bool force_not_profitable = false;
if (orig_loop && flag_vect_cost_model == VECT_COST_MODEL_VERY_CHEAP)
{
gcc_assert (bb_vinfo->bbs.length () == 1);
for (gimple_stmt_iterator gsi = gsi_start_bb (bb_vinfo->bbs[0]);
!gsi_end_p (gsi); gsi_next (&gsi))
{
/* The costing above left us with DCEable vectorized scalar
stmts having the visited flag set. */
if (gimple_visited_p (gsi_stmt (gsi)))
continue;
if (gassign *ass = dyn_cast <gassign *> (gsi_stmt (gsi)))
if (gimple_assign_rhs_code (ass) == COND_EXPR)
{
force_not_profitable = true;
break;
}
}
}
/* Unset visited flag. */
stmt_info_for_cost *cost;
FOR_EACH_VEC_ELT (scalar_costs, i, cost)
@ -5394,9 +5419,14 @@ vect_bb_vectorization_profitable_p (bb_vec_info bb_vinfo,
return false;
}
if (dump_enabled_p () && force_not_profitable)
dump_printf_loc (MSG_NOTE, vect_location,
"not profitable because of unprofitable if-converted "
"scalar code\n");
scalar_costs.release ();
vector_costs.release ();
return true;
return !force_not_profitable;
}
/* qsort comparator for lane defs. */
@ -5810,7 +5840,8 @@ vect_slp_analyze_bb_1 (bb_vec_info bb_vinfo, int n_stmts, bool &fatal,
static bool
vect_slp_region (vec<basic_block> bbs, vec<data_reference_p> datarefs,
vec<int> *dataref_groups, unsigned int n_stmts)
vec<int> *dataref_groups, unsigned int n_stmts,
loop_p orig_loop)
{
bb_vec_info bb_vinfo;
auto_vector_modes vector_modes;
@ -5859,7 +5890,9 @@ vect_slp_region (vec<basic_block> bbs, vec<data_reference_p> datarefs,
vect_location = instance->location ();
if (!unlimited_cost_model (NULL)
&& !vect_bb_vectorization_profitable_p
(bb_vinfo, instance->subgraph_entries))
(bb_vinfo,
orig_loop ? BB_VINFO_SLP_INSTANCES (bb_vinfo)
: instance->subgraph_entries, orig_loop))
{
if (dump_enabled_p ())
dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
@ -5877,7 +5910,9 @@ vect_slp_region (vec<basic_block> bbs, vec<data_reference_p> datarefs,
"using SLP\n");
vectorized = true;
vect_schedule_slp (bb_vinfo, instance->subgraph_entries);
vect_schedule_slp (bb_vinfo,
orig_loop ? BB_VINFO_SLP_INSTANCES (bb_vinfo)
: instance->subgraph_entries);
unsigned HOST_WIDE_INT bytes;
if (dump_enabled_p ())
@ -5892,6 +5927,11 @@ vect_slp_region (vec<basic_block> bbs, vec<data_reference_p> datarefs,
"basic block part vectorized using "
"variable length vectors\n");
}
/* When we're called from loop vectorization we're considering
all subgraphs at once. */
if (orig_loop)
break;
}
}
else
@ -5959,7 +5999,7 @@ vect_slp_region (vec<basic_block> bbs, vec<data_reference_p> datarefs,
true if anything in the basic-block was vectorized. */
static bool
vect_slp_bbs (const vec<basic_block> &bbs)
vect_slp_bbs (const vec<basic_block> &bbs, loop_p orig_loop)
{
vec<data_reference_p> datarefs = vNULL;
auto_vec<int> dataref_groups;
@ -5989,18 +6029,20 @@ vect_slp_bbs (const vec<basic_block> &bbs)
++current_group;
}
return vect_slp_region (bbs, datarefs, &dataref_groups, insns);
return vect_slp_region (bbs, datarefs, &dataref_groups, insns, orig_loop);
}
/* Main entry for the BB vectorizer. Analyze and transform BB, returns
true if anything in the basic-block was vectorized. */
/* Special entry for the BB vectorizer. Analyze and transform a single
if-converted BB with ORIG_LOOPs body being the not if-converted
representation. Returns true if anything in the basic-block was
vectorized. */
bool
vect_slp_bb (basic_block bb)
vect_slp_if_converted_bb (basic_block bb, loop_p orig_loop)
{
auto_vec<basic_block> bbs;
bbs.safe_push (bb);
return vect_slp_bbs (bbs);
return vect_slp_bbs (bbs, orig_loop);
}
/* Main entry for the BB vectorizer. Analyze and transform BB, returns
@ -6051,7 +6093,7 @@ vect_slp_function (function *fun)
if (split && !bbs.is_empty ())
{
r |= vect_slp_bbs (bbs);
r |= vect_slp_bbs (bbs, NULL);
bbs.truncate (0);
bbs.quick_push (bb);
}
@ -6069,13 +6111,13 @@ vect_slp_function (function *fun)
dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
"splitting region at control altering "
"definition %G", last);
r |= vect_slp_bbs (bbs);
r |= vect_slp_bbs (bbs, NULL);
bbs.truncate (0);
}
}
if (!bbs.is_empty ())
r |= vect_slp_bbs (bbs);
r |= vect_slp_bbs (bbs, NULL);
free (rpo);

20
gcc/tree-vectorizer.c
View File

@ -1033,10 +1033,7 @@ try_vectorize_loop_1 (hash_table<simduid_to_vf> *&simduid_to_vf_htab,
only non-if-converted parts took part in BB vectorization. */
if (flag_tree_slp_vectorize != 0
&& loop_vectorized_call
&& ! loop->inner
/* This would purely be a workaround and should be removed
once PR100089 is fixed. */
&& flag_vect_cost_model != VECT_COST_MODEL_VERY_CHEAP)
&& ! loop->inner)
{
basic_block bb = loop->header;
bool require_loop_vectorize = false;
@ -1062,12 +1059,17 @@ try_vectorize_loop_1 (hash_table<simduid_to_vf> *&simduid_to_vf_htab,
gimple_set_uid (stmt, -1);
gimple_set_visited (stmt, false);
}
if (!require_loop_vectorize && vect_slp_bb (bb))
if (!require_loop_vectorize)
{
fold_loop_internal_call (loop_vectorized_call,
boolean_true_node);
loop_vectorized_call = NULL;
ret |= TODO_cleanup_cfg | TODO_update_ssa_only_virtuals;
tree arg = gimple_call_arg (loop_vectorized_call, 1);
class loop *scalar_loop = get_loop (cfun, tree_to_shwi (arg));
if (vect_slp_if_converted_bb (bb, scalar_loop))
{
fold_loop_internal_call (loop_vectorized_call,
boolean_true_node);
loop_vectorized_call = NULL;
ret |= TODO_cleanup_cfg | TODO_update_ssa_only_virtuals;
}
}
}
/* If outer loop vectorization fails for LOOP_VECTORIZED guarded

2
gcc/tree-vectorizer.h
View File

@ -2087,7 +2087,7 @@ extern void vect_gather_slp_loads (vec_info *);
extern void vect_get_slp_defs (slp_tree, vec<tree> *);
extern void vect_get_slp_defs (vec_info *, slp_tree, vec<vec<tree> > *,
unsigned n = -1U);
extern bool vect_slp_bb (basic_block);
extern bool vect_slp_if_converted_bb (basic_block bb, loop_p orig_loop);
extern bool vect_slp_function (function *);
extern stmt_vec_info vect_find_last_scalar_stmt_in_slp (slp_tree);
extern stmt_vec_info vect_find_first_scalar_stmt_in_slp (slp_tree);