#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"
}
\f
+/* 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. */
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))
{
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. */
initialize_scalar_evolutions_analyzer ();
+ peeled_chrec_map = pointer_map_create ();
+
FOR_EACH_LOOP (loop, 0)
{
loop->nb_iterations = NULL_TREE;
scev_reset_htab ();
+ if (peeled_chrec_map)
+ {
+ pointer_map_destroy (peeled_chrec_map);
+ peeled_chrec_map = NULL;
+ }
+
if (!current_loops)
return;
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
/* 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);
}
}