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re PR tree-optimization/41488 (IVOpts cannot coalesce multiple induction variables)

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PR tree-optimization/41488
	* tree-ssa-loop-ivopts.c (add_old_iv_candidates): Don't add cand
	for PEELED_CHREC kind IV.
	* tree-scalar-evolution.c: Include necessary header files.
	(peeled_chrec_map, simplify_peeled_chrec): New.
	(analyze_evolution_in_loop): New static variable.
	Call simplify_peeled_chrec.
	(scev_initialize): Initialize peeled_chrec_map.
	(scev_reset, scev_finalize): Reset and release peeled_chrec_map.

	PR tree-optimization/41488
	* gcc.dg/tree-ssa/scev-7.c: New test.
	* gcc.dg/pr41488.c: New test.

From-SVN: r205848
This commit is contained in:
Bin Cheng 2013-12-10 06:31:41 +00:00 • committed by Bin Cheng
parent 3a4efce7c2
commit f644a018e3
6 changed files with 156 additions and 6 deletions
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12
gcc/ChangeLog
View file

@ -1,3 +1,15 @@
2013-12-10 Bin Cheng <bin.cheng@arm.com>
PR tree-optimization/41488
* tree-ssa-loop-ivopts.c (add_old_iv_candidates): Don't add cand
for PEELED_CHREC kind IV.
* tree-scalar-evolution.c: Include necessary header files.
(peeled_chrec_map, simplify_peeled_chrec): New.
(analyze_evolution_in_loop): New static variable.
Call simplify_peeled_chrec.
(scev_initialize): Initialize peeled_chrec_map.
(scev_reset, scev_finalize): Reset and release peeled_chrec_map.
2013-12-09 Andrew Pinski <apinski@cavium.com>
* config/aarch64/t-aarch64 (MULTILIB_OPTIONS): Fix definition so

6
gcc/testsuite/ChangeLog
View file

@ -1,3 +1,9 @@
2013-12-10 Bin Cheng <bin.cheng@arm.com>
PR tree-optimization/41488
* gcc.dg/tree-ssa/scev-7.c: New test.
* gcc.dg/pr41488.c: New test.
2013-12-09 Joseph Myers <joseph@codesourcery.com>
PR preprocessor/55715

18
gcc/testsuite/gcc.dg/pr41488.c Normal file
View file

@ -0,0 +1,18 @@
/* { dg-do compile } */
/* { dg-options "-O2 -fdump-tree-sccp-scev" } */
struct struct_t
{
int* data;
};
void foo (struct struct_t* sp, int start, int end)
{
int i;
for (i = 0; i+start < end; i++)
sp->data[i+start] = 0;
}
/* { dg-final { scan-tree-dump-times "Simplify PEELED_CHREC into POLYNOMIAL_CHREC" 1 "sccp" } } */
/* { dg-final { cleanup-tree-dump "sccp" } } */

18
gcc/testsuite/gcc.dg/tree-ssa/scev-7.c Normal file
View file

@ -0,0 +1,18 @@
/* { dg-do compile } */
/* { dg-options "-O2 -fdump-tree-sccp-scev" } */
struct struct_t
{
int* data;
};
void foo (struct struct_t* sp, int start, int end)
{
int i;
for (i = 1000; i+start > end; i--)
sp->data[i+start] = 0;
}
/* { dg-final { scan-tree-dump-times "Simplify PEELED_CHREC into POLYNOMIAL_CHREC" 1 "sccp" } } */
/* { dg-final { cleanup-tree-dump "sccp" } } */

90
gcc/tree-scalar-evolution.c
View file

@ -280,6 +280,8 @@ along with GCC; see the file COPYING3. If not see
#include "tree-ssa.h"
#include "cfgloop.h"
#include "tree-chrec.h"
#include "pointer-set.h"
#include "tree-affine.h"
#include "tree-scalar-evolution.h"
#include "dumpfile.h"
#include "params.h"
@ -1380,6 +1382,66 @@ follow_ssa_edge (struct loop *loop, gimple def, gimple halting_phi,
}
/* Pointer map used when simplifying PEELED_CHREC into POLYNOMIAL_CHREC. */
static pointer_map_t *peeled_chrec_map;
/* Simplify PEELED_CHREC represented by (init_cond, arg) in LOOP.
Handle below case and return the corresponding POLYNOMIAL_CHREC:
# i_17 = PHI <i_13(5), 0(3)>
# _20 = PHI <_5(5), start_4(D)(3)>
...
i_13 = i_17 + 1;
_5 = start_4(D) + i_13;
Though variable _20 appears as a PEELED_CHREC in the form of
(start_4, _5)_LOOP, it's a POLYNOMIAL_CHREC like {start_4, 1}_LOOP.
See PR41488. */
static tree
simplify_peeled_chrec (struct loop *loop, tree arg, tree init_cond)
{
aff_tree aff1, aff2;
tree ev, left, right, type, step_val;
ev = instantiate_parameters (loop, analyze_scalar_evolution (loop, arg));
if (ev == NULL_TREE || TREE_CODE (ev) != POLYNOMIAL_CHREC)
return chrec_dont_know;
left = CHREC_LEFT (ev);
right = CHREC_RIGHT (ev);
type = TREE_TYPE (left);
step_val = chrec_fold_plus (type, init_cond, right);
/* Transform (init, {left, right}_LOOP)_LOOP to {init, right}_LOOP
if "left" equals to "init + right". */
if (operand_equal_p (left, step_val, 0))
{
if (dump_file && (dump_flags & TDF_SCEV))
fprintf (dump_file, "Simplify PEELED_CHREC into POLYNOMIAL_CHREC.\n");
return build_polynomial_chrec (loop->num, init_cond, right);
}
/* Try harder to check if they are equal. */
tree_to_aff_combination_expand (left, type, &aff1, &peeled_chrec_map);
tree_to_aff_combination_expand (step_val, type, &aff2, &peeled_chrec_map);
aff_combination_scale (&aff2, double_int_minus_one);
aff_combination_add (&aff1, &aff2);
left = fold_convert (type, aff_combination_to_tree (&aff1));
/* Transform (init, {left, right}_LOOP)_LOOP to {init, right}_LOOP
if "left" equals to "init + right". */
if (operand_equal_p (left, integer_zero_node, 0))
{
if (dump_file && (dump_flags & TDF_SCEV))
fprintf (dump_file, "Simplify PEELED_CHREC into POLYNOMIAL_CHREC.\n");
return build_polynomial_chrec (loop->num, init_cond, right);
}
return chrec_dont_know;
}
/* Given a LOOP_PHI_NODE, this function determines the evolution
function from LOOP_PHI_NODE to LOOP_PHI_NODE in the loop. */
@ -1392,6 +1454,7 @@ analyze_evolution_in_loop (gimple loop_phi_node,
tree evolution_function = chrec_not_analyzed_yet;
struct loop *loop = loop_containing_stmt (loop_phi_node);
basic_block bb;
static bool simplify_peeled_chrec_p = true;
if (dump_file && (dump_flags & TDF_SCEV))
{
@ -1442,7 +1505,19 @@ analyze_evolution_in_loop (gimple loop_phi_node,
all the other iterations it has the value of ARG.
For the moment, PEELED_CHREC nodes are not built. */
if (res != t_true)
ev_fn = chrec_dont_know;
{
ev_fn = chrec_dont_know;
/* Try to recognize POLYNOMIAL_CHREC which appears in
the form of PEELED_CHREC, but guard the process with
a bool variable to keep the analyzer from infinite
recurrence for real PEELED_RECs. */
if (simplify_peeled_chrec_p && TREE_CODE (arg) == SSA_NAME)
{
simplify_peeled_chrec_p = false;
ev_fn = simplify_peeled_chrec (loop, arg, init_cond);
simplify_peeled_chrec_p = true;
}
}
/* When there are multiple back edges of the loop (which in fact never
happens currently, but nevertheless), merge their evolutions. */
@ -3086,6 +3161,8 @@ scev_initialize (void)
initialize_scalar_evolutions_analyzer ();
peeled_chrec_map = pointer_map_create ();
FOR_EACH_LOOP (loop, 0)
{
loop->nb_iterations = NULL_TREE;
@ -3122,6 +3199,12 @@ scev_reset (void)
scev_reset_htab ();
if (peeled_chrec_map)
{
pointer_map_destroy (peeled_chrec_map);
peeled_chrec_map = NULL;
}
if (!current_loops)
return;
@ -3209,6 +3292,11 @@ scev_finalize (void)
return;
htab_delete (scalar_evolution_info);
scalar_evolution_info = NULL;
if (peeled_chrec_map)
{
pointer_map_destroy (peeled_chrec_map);
peeled_chrec_map = NULL;
}
}
/* Returns true if the expression EXPR is considered to be too expensive

18
gcc/tree-ssa-loop-ivopts.c
View file

@ -2526,11 +2526,19 @@ add_old_iv_candidates (struct ivopts_data *data, struct iv *iv)
/* Additionally record the possibility of leaving the original iv
untouched. */
def = PHI_ARG_DEF_FROM_EDGE (phi, loop_latch_edge (data->current_loop));
cand = add_candidate_1 (data,
iv->base, iv->step, true, IP_ORIGINAL, NULL,
SSA_NAME_DEF_STMT (def));
cand->var_before = iv->ssa_name;
cand->var_after = def;
/* Don't add candidate if it's from another PHI node because
it's an affine iv appearing in the form of PEELED_CHREC. */
phi = SSA_NAME_DEF_STMT (def);
if (gimple_code (phi) != GIMPLE_PHI)
{
cand = add_candidate_1 (data,
iv->base, iv->step, true, IP_ORIGINAL, NULL,
SSA_NAME_DEF_STMT (def));
cand->var_before = iv->ssa_name;
cand->var_after = def;
}
else
gcc_assert (gimple_bb (phi) == data->current_loop->header);
}
}