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Do final value replacement in try_create_reduction_list

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2015-11-20  Tom de Vries  <tom@codesourcery.com>

	PR tree-optimization/68373
	* tree-scalar-evolution.c (final_value_replacement_loop): Factor out of ...
	(scev_const_prop): ... here.
	* tree-scalar-evolution.h (final_value_replacement_loop): Declare.
	* tree-parloops.c (try_create_reduction_list): Call
	final_value_replacement_loop.

	* gcc.dg/autopar/pr68373.c: New test.

From-SVN: r230650
This commit is contained in:
Tom de Vries 2015-11-20 10:25:26 +00:00 • committed by Tom de Vries
parent 5b5e7b181f
commit f993a85385
6 changed files with 159 additions and 121 deletions
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9
gcc/ChangeLog
View file

@ -1,3 +1,12 @@
2015-11-20 Tom de Vries <tom@codesourcery.com>
PR tree-optimization/68373
* tree-scalar-evolution.c (final_value_replacement_loop): Factor out of ...
(scev_const_prop): ... here.
* tree-scalar-evolution.h (final_value_replacement_loop): Declare.
* tree-parloops.c (try_create_reduction_list): Call
final_value_replacement_loop.
2015-11-20 Bin Cheng <bin.cheng@arm.com>
PR tree-optimization/52272

5
gcc/testsuite/ChangeLog
View file

@ -1,3 +1,8 @@
2015-11-20 Tom de Vries <tom@codesourcery.com>
PR tree-optimization/68373
* gcc.dg/autopar/pr68373.c: New test.
2015-11-20 Jakub Jelinek <jakub@redhat.com>
PR c++/67354

14
gcc/testsuite/gcc.dg/autopar/pr68373.c Normal file
View file

@ -0,0 +1,14 @@
/* { dg-do compile } */
/* { dg-options "-O2 -ftree-parallelize-loops=2 -fdump-tree-parloops-details" } */
unsigned int
foo (int *a, unsigned int n)
{
unsigned int i;
for (i = 0; i < n; ++i)
a[i] = 1;
return i;
}
/* { dg-final { scan-tree-dump-times "SUCCESS: may be parallelized" 1 "parloops" } } */

3
gcc/tree-parloops.c
View file

@ -2539,6 +2539,9 @@ try_create_reduction_list (loop_p loop,
gcc_assert (exit);
/* Try to get rid of exit phis. */
final_value_replacement_loop (loop);
gather_scalar_reductions (loop, reduction_list);

248
gcc/tree-scalar-evolution.c
View file

@ -3417,6 +3417,131 @@ expression_expensive_p (tree expr)
}
}
/* Do final value replacement for LOOP. */
void
final_value_replacement_loop (struct loop *loop)
{
/* If we do not know exact number of iterations of the loop, we cannot
replace the final value. */
edge exit = single_exit (loop);
if (!exit)
return;
tree niter = number_of_latch_executions (loop);
if (niter == chrec_dont_know)
return;
/* Ensure that it is possible to insert new statements somewhere. */
if (!single_pred_p (exit->dest))
split_loop_exit_edge (exit);
/* Set stmt insertion pointer. All stmts are inserted before this point. */
gimple_stmt_iterator gsi = gsi_after_labels (exit->dest);
struct loop *ex_loop
= superloop_at_depth (loop,
loop_depth (exit->dest->loop_father) + 1);
gphi_iterator psi;
for (psi = gsi_start_phis (exit->dest); !gsi_end_p (psi); )
{
gphi *phi = psi.phi ();
tree rslt = PHI_RESULT (phi);
tree def = PHI_ARG_DEF_FROM_EDGE (phi, exit);
if (virtual_operand_p (def))
{
gsi_next (&psi);
continue;
}
if (!POINTER_TYPE_P (TREE_TYPE (def))
&& !INTEGRAL_TYPE_P (TREE_TYPE (def)))
{
gsi_next (&psi);
continue;
}
bool folded_casts;
def = analyze_scalar_evolution_in_loop (ex_loop, loop, def,
&folded_casts);
def = compute_overall_effect_of_inner_loop (ex_loop, def);
if (!tree_does_not_contain_chrecs (def)
|| chrec_contains_symbols_defined_in_loop (def, ex_loop->num)
/* Moving the computation from the loop may prolong life range
of some ssa names, which may cause problems if they appear
on abnormal edges. */
|| contains_abnormal_ssa_name_p (def)
/* Do not emit expensive expressions. The rationale is that
when someone writes a code like
while (n > 45) n -= 45;
he probably knows that n is not large, and does not want it
to be turned into n %= 45. */
|| expression_expensive_p (def))
{
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "not replacing:\n ");
print_gimple_stmt (dump_file, phi, 0, 0);
fprintf (dump_file, "\n");
}
gsi_next (&psi);
continue;
}
/* Eliminate the PHI node and replace it by a computation outside
the loop. */
if (dump_file)
{
fprintf (dump_file, "\nfinal value replacement:\n ");
print_gimple_stmt (dump_file, phi, 0, 0);
fprintf (dump_file, " with\n ");
}
def = unshare_expr (def);
remove_phi_node (&psi, false);
/* If def's type has undefined overflow and there were folded
casts, rewrite all stmts added for def into arithmetics
with defined overflow behavior. */
if (folded_casts && ANY_INTEGRAL_TYPE_P (TREE_TYPE (def))
&& TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (def)))
{
gimple_seq stmts;
gimple_stmt_iterator gsi2;
def = force_gimple_operand (def, &stmts, true, NULL_TREE);
gsi2 = gsi_start (stmts);
while (!gsi_end_p (gsi2))
{
gimple *stmt = gsi_stmt (gsi2);
gimple_stmt_iterator gsi3 = gsi2;
gsi_next (&gsi2);
gsi_remove (&gsi3, false);
if (is_gimple_assign (stmt)
&& arith_code_with_undefined_signed_overflow
(gimple_assign_rhs_code (stmt)))
gsi_insert_seq_before (&gsi,
rewrite_to_defined_overflow (stmt),
GSI_SAME_STMT);
else
gsi_insert_before (&gsi, stmt, GSI_SAME_STMT);
}
}
else
def = force_gimple_operand_gsi (&gsi, def, false, NULL_TREE,
true, GSI_SAME_STMT);
gassign *ass = gimple_build_assign (rslt, def);
gsi_insert_before (&gsi, ass, GSI_SAME_STMT);
if (dump_file)
{
print_gimple_stmt (dump_file, ass, 0, 0);
fprintf (dump_file, "\n");
}
}
}
/* Replace ssa names for that scev can prove they are constant by the
appropriate constants. Also perform final value replacement in loops,
in case the replacement expressions are cheap.
@ -3430,8 +3555,7 @@ scev_const_prop (void)
basic_block bb;
tree name, type, ev;
gphi *phi;
gassign *ass;
struct loop *loop, *ex_loop;
struct loop *loop;
bitmap ssa_names_to_remove = NULL;
unsigned i;
gphi_iterator psi;
@ -3507,126 +3631,8 @@ scev_const_prop (void)
/* Now the regular final value replacement. */
FOR_EACH_LOOP (loop, LI_FROM_INNERMOST)
{
edge exit;
tree def, rslt, niter;
gimple_stmt_iterator gsi;
final_value_replacement_loop (loop);
/* If we do not know exact number of iterations of the loop, we cannot
replace the final value. */
exit = single_exit (loop);
if (!exit)
continue;
niter = number_of_latch_executions (loop);
if (niter == chrec_dont_know)
continue;
/* Ensure that it is possible to insert new statements somewhere. */
if (!single_pred_p (exit->dest))
split_loop_exit_edge (exit);
gsi = gsi_after_labels (exit->dest);
ex_loop = superloop_at_depth (loop,
loop_depth (exit->dest->loop_father) + 1);
for (psi = gsi_start_phis (exit->dest); !gsi_end_p (psi); )
{
phi = psi.phi ();
rslt = PHI_RESULT (phi);
def = PHI_ARG_DEF_FROM_EDGE (phi, exit);
if (virtual_operand_p (def))
{
gsi_next (&psi);
continue;
}
if (!POINTER_TYPE_P (TREE_TYPE (def))
&& !INTEGRAL_TYPE_P (TREE_TYPE (def)))
{
gsi_next (&psi);
continue;
}
bool folded_casts;
def = analyze_scalar_evolution_in_loop (ex_loop, loop, def,
&folded_casts);
def = compute_overall_effect_of_inner_loop (ex_loop, def);
if (!tree_does_not_contain_chrecs (def)
|| chrec_contains_symbols_defined_in_loop (def, ex_loop->num)
/* Moving the computation from the loop may prolong life range
of some ssa names, which may cause problems if they appear
on abnormal edges. */
|| contains_abnormal_ssa_name_p (def)
/* Do not emit expensive expressions. The rationale is that
when someone writes a code like
while (n > 45) n -= 45;
he probably knows that n is not large, and does not want it
to be turned into n %= 45. */
|| expression_expensive_p (def))
{
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "not replacing:\n ");
print_gimple_stmt (dump_file, phi, 0, 0);
fprintf (dump_file, "\n");
}
gsi_next (&psi);
continue;
}
/* Eliminate the PHI node and replace it by a computation outside
the loop. */
if (dump_file)
{
fprintf (dump_file, "\nfinal value replacement:\n ");
print_gimple_stmt (dump_file, phi, 0, 0);
fprintf (dump_file, " with\n ");
}
def = unshare_expr (def);
remove_phi_node (&psi, false);
/* If def's type has undefined overflow and there were folded
casts, rewrite all stmts added for def into arithmetics
with defined overflow behavior. */
if (folded_casts && ANY_INTEGRAL_TYPE_P (TREE_TYPE (def))
&& TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (def)))
{
gimple_seq stmts;
gimple_stmt_iterator gsi2;
def = force_gimple_operand (def, &stmts, true, NULL_TREE);
gsi2 = gsi_start (stmts);
while (!gsi_end_p (gsi2))
{
gimple *stmt = gsi_stmt (gsi2);
gimple_stmt_iterator gsi3 = gsi2;
gsi_next (&gsi2);
gsi_remove (&gsi3, false);
if (is_gimple_assign (stmt)
&& arith_code_with_undefined_signed_overflow
(gimple_assign_rhs_code (stmt)))
gsi_insert_seq_before (&gsi,
rewrite_to_defined_overflow (stmt),
GSI_SAME_STMT);
else
gsi_insert_before (&gsi, stmt, GSI_SAME_STMT);
}
}
else
def = force_gimple_operand_gsi (&gsi, def, false, NULL_TREE,
true, GSI_SAME_STMT);
ass = gimple_build_assign (rslt, def);
gsi_insert_before (&gsi, ass, GSI_SAME_STMT);
if (dump_file)
{
print_gimple_stmt (dump_file, ass, 0, 0);
fprintf (dump_file, "\n");
}
}
}
return 0;
}

1
gcc/tree-scalar-evolution.h
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@ -33,6 +33,7 @@ extern tree analyze_scalar_evolution (struct loop *, tree);
extern tree instantiate_scev (basic_block, struct loop *, tree);
extern tree resolve_mixers (struct loop *, tree, bool *);
extern void gather_stats_on_scev_database (void);
extern void final_value_replacement_loop (struct loop *);
extern unsigned int scev_const_prop (void);
extern bool expression_expensive_p (tree);
extern bool simple_iv (struct loop *, struct loop *, tree, struct affine_iv *,