forked from illumos/gcc
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tree-chrec.c
1494 lines (1229 loc) · 39.8 KB
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tree-chrec.c
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/* Chains of recurrences.
Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009
Free Software Foundation, Inc.
Contributed by Sebastian Pop <pop@cri.ensmp.fr>
This file is part of GCC.
GCC is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 3, or (at your option) any later
version.
GCC is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
for more details.
You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING3. If not see
<http://www.gnu.org/licenses/>. */
/* This file implements operations on chains of recurrences. Chains
of recurrences are used for modeling evolution functions of scalar
variables.
*/
#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include "ggc.h"
#include "tree.h"
#include "real.h"
#include "diagnostic.h"
#include "cfgloop.h"
#include "tree-flow.h"
#include "tree-chrec.h"
#include "tree-pass.h"
#include "params.h"
#include "tree-scalar-evolution.h"
/* Extended folder for chrecs. */
/* Determines whether CST is not a constant evolution. */
static inline bool
is_not_constant_evolution (const_tree cst)
{
return (TREE_CODE (cst) == POLYNOMIAL_CHREC);
}
/* Fold CODE for a polynomial function and a constant. */
static inline tree
chrec_fold_poly_cst (enum tree_code code,
tree type,
tree poly,
tree cst)
{
gcc_assert (poly);
gcc_assert (cst);
gcc_assert (TREE_CODE (poly) == POLYNOMIAL_CHREC);
gcc_assert (!is_not_constant_evolution (cst));
gcc_assert (type == chrec_type (poly));
switch (code)
{
case PLUS_EXPR:
return build_polynomial_chrec
(CHREC_VARIABLE (poly),
chrec_fold_plus (type, CHREC_LEFT (poly), cst),
CHREC_RIGHT (poly));
case MINUS_EXPR:
return build_polynomial_chrec
(CHREC_VARIABLE (poly),
chrec_fold_minus (type, CHREC_LEFT (poly), cst),
CHREC_RIGHT (poly));
case MULT_EXPR:
return build_polynomial_chrec
(CHREC_VARIABLE (poly),
chrec_fold_multiply (type, CHREC_LEFT (poly), cst),
chrec_fold_multiply (type, CHREC_RIGHT (poly), cst));
default:
return chrec_dont_know;
}
}
/* Fold the addition of two polynomial functions. */
static inline tree
chrec_fold_plus_poly_poly (enum tree_code code,
tree type,
tree poly0,
tree poly1)
{
tree left, right;
struct loop *loop0 = get_chrec_loop (poly0);
struct loop *loop1 = get_chrec_loop (poly1);
tree rtype = code == POINTER_PLUS_EXPR ? sizetype : type;
gcc_assert (poly0);
gcc_assert (poly1);
gcc_assert (TREE_CODE (poly0) == POLYNOMIAL_CHREC);
gcc_assert (TREE_CODE (poly1) == POLYNOMIAL_CHREC);
if (POINTER_TYPE_P (chrec_type (poly0)))
gcc_assert (chrec_type (poly1) == sizetype);
else
gcc_assert (chrec_type (poly0) == chrec_type (poly1));
gcc_assert (type == chrec_type (poly0));
/*
{a, +, b}_1 + {c, +, d}_2 -> {{a, +, b}_1 + c, +, d}_2,
{a, +, b}_2 + {c, +, d}_1 -> {{c, +, d}_1 + a, +, b}_2,
{a, +, b}_x + {c, +, d}_x -> {a+c, +, b+d}_x. */
if (flow_loop_nested_p (loop0, loop1))
{
if (code == PLUS_EXPR || code == POINTER_PLUS_EXPR)
return build_polynomial_chrec
(CHREC_VARIABLE (poly1),
chrec_fold_plus (type, poly0, CHREC_LEFT (poly1)),
CHREC_RIGHT (poly1));
else
return build_polynomial_chrec
(CHREC_VARIABLE (poly1),
chrec_fold_minus (type, poly0, CHREC_LEFT (poly1)),
chrec_fold_multiply (type, CHREC_RIGHT (poly1),
SCALAR_FLOAT_TYPE_P (type)
? build_real (type, dconstm1)
: build_int_cst_type (type, -1)));
}
if (flow_loop_nested_p (loop1, loop0))
{
if (code == PLUS_EXPR || code == POINTER_PLUS_EXPR)
return build_polynomial_chrec
(CHREC_VARIABLE (poly0),
chrec_fold_plus (type, CHREC_LEFT (poly0), poly1),
CHREC_RIGHT (poly0));
else
return build_polynomial_chrec
(CHREC_VARIABLE (poly0),
chrec_fold_minus (type, CHREC_LEFT (poly0), poly1),
CHREC_RIGHT (poly0));
}
/* This function should never be called for chrecs of loops that
do not belong to the same loop nest. */
gcc_assert (loop0 == loop1);
if (code == PLUS_EXPR || code == POINTER_PLUS_EXPR)
{
left = chrec_fold_plus
(type, CHREC_LEFT (poly0), CHREC_LEFT (poly1));
right = chrec_fold_plus
(rtype, CHREC_RIGHT (poly0), CHREC_RIGHT (poly1));
}
else
{
left = chrec_fold_minus
(type, CHREC_LEFT (poly0), CHREC_LEFT (poly1));
right = chrec_fold_minus
(type, CHREC_RIGHT (poly0), CHREC_RIGHT (poly1));
}
if (chrec_zerop (right))
return left;
else
return build_polynomial_chrec
(CHREC_VARIABLE (poly0), left, right);
}
/* Fold the multiplication of two polynomial functions. */
static inline tree
chrec_fold_multiply_poly_poly (tree type,
tree poly0,
tree poly1)
{
tree t0, t1, t2;
int var;
struct loop *loop0 = get_chrec_loop (poly0);
struct loop *loop1 = get_chrec_loop (poly1);
gcc_assert (poly0);
gcc_assert (poly1);
gcc_assert (TREE_CODE (poly0) == POLYNOMIAL_CHREC);
gcc_assert (TREE_CODE (poly1) == POLYNOMIAL_CHREC);
gcc_assert (chrec_type (poly0) == chrec_type (poly1));
gcc_assert (type == chrec_type (poly0));
/* {a, +, b}_1 * {c, +, d}_2 -> {c*{a, +, b}_1, +, d}_2,
{a, +, b}_2 * {c, +, d}_1 -> {a*{c, +, d}_1, +, b}_2,
{a, +, b}_x * {c, +, d}_x -> {a*c, +, a*d + b*c + b*d, +, 2*b*d}_x. */
if (flow_loop_nested_p (loop0, loop1))
/* poly0 is a constant wrt. poly1. */
return build_polynomial_chrec
(CHREC_VARIABLE (poly1),
chrec_fold_multiply (type, CHREC_LEFT (poly1), poly0),
CHREC_RIGHT (poly1));
if (flow_loop_nested_p (loop1, loop0))
/* poly1 is a constant wrt. poly0. */
return build_polynomial_chrec
(CHREC_VARIABLE (poly0),
chrec_fold_multiply (type, CHREC_LEFT (poly0), poly1),
CHREC_RIGHT (poly0));
gcc_assert (loop0 == loop1);
/* poly0 and poly1 are two polynomials in the same variable,
{a, +, b}_x * {c, +, d}_x -> {a*c, +, a*d + b*c + b*d, +, 2*b*d}_x. */
/* "a*c". */
t0 = chrec_fold_multiply (type, CHREC_LEFT (poly0), CHREC_LEFT (poly1));
/* "a*d + b*c + b*d". */
t1 = chrec_fold_multiply (type, CHREC_LEFT (poly0), CHREC_RIGHT (poly1));
t1 = chrec_fold_plus (type, t1, chrec_fold_multiply (type,
CHREC_RIGHT (poly0),
CHREC_LEFT (poly1)));
t1 = chrec_fold_plus (type, t1, chrec_fold_multiply (type,
CHREC_RIGHT (poly0),
CHREC_RIGHT (poly1)));
/* "2*b*d". */
t2 = chrec_fold_multiply (type, CHREC_RIGHT (poly0), CHREC_RIGHT (poly1));
t2 = chrec_fold_multiply (type, SCALAR_FLOAT_TYPE_P (type)
? build_real (type, dconst2)
: build_int_cst (type, 2), t2);
var = CHREC_VARIABLE (poly0);
return build_polynomial_chrec (var, t0,
build_polynomial_chrec (var, t1, t2));
}
/* When the operands are automatically_generated_chrec_p, the fold has
to respect the semantics of the operands. */
static inline tree
chrec_fold_automatically_generated_operands (tree op0,
tree op1)
{
if (op0 == chrec_dont_know
|| op1 == chrec_dont_know)
return chrec_dont_know;
if (op0 == chrec_known
|| op1 == chrec_known)
return chrec_known;
if (op0 == chrec_not_analyzed_yet
|| op1 == chrec_not_analyzed_yet)
return chrec_not_analyzed_yet;
/* The default case produces a safe result. */
return chrec_dont_know;
}
/* Fold the addition of two chrecs. */
static tree
chrec_fold_plus_1 (enum tree_code code, tree type,
tree op0, tree op1)
{
tree op1_type = code == POINTER_PLUS_EXPR ? sizetype : type;
if (automatically_generated_chrec_p (op0)
|| automatically_generated_chrec_p (op1))
return chrec_fold_automatically_generated_operands (op0, op1);
switch (TREE_CODE (op0))
{
case POLYNOMIAL_CHREC:
switch (TREE_CODE (op1))
{
case POLYNOMIAL_CHREC:
return chrec_fold_plus_poly_poly (code, type, op0, op1);
default:
if (code == PLUS_EXPR || code == POINTER_PLUS_EXPR)
return build_polynomial_chrec
(CHREC_VARIABLE (op0),
chrec_fold_plus (type, CHREC_LEFT (op0), op1),
CHREC_RIGHT (op0));
else
return build_polynomial_chrec
(CHREC_VARIABLE (op0),
chrec_fold_minus (type, CHREC_LEFT (op0), op1),
CHREC_RIGHT (op0));
}
default:
switch (TREE_CODE (op1))
{
case POLYNOMIAL_CHREC:
if (code == PLUS_EXPR || code == POINTER_PLUS_EXPR)
return build_polynomial_chrec
(CHREC_VARIABLE (op1),
chrec_fold_plus (type, op0, CHREC_LEFT (op1)),
CHREC_RIGHT (op1));
else
return build_polynomial_chrec
(CHREC_VARIABLE (op1),
chrec_fold_minus (type, op0, CHREC_LEFT (op1)),
chrec_fold_multiply (type, CHREC_RIGHT (op1),
SCALAR_FLOAT_TYPE_P (type)
? build_real (type, dconstm1)
: build_int_cst_type (type, -1)));
default:
{
int size = 0;
if ((tree_contains_chrecs (op0, &size)
|| tree_contains_chrecs (op1, &size))
&& size < PARAM_VALUE (PARAM_SCEV_MAX_EXPR_SIZE))
return build2 (code, type, op0, op1);
else if (size < PARAM_VALUE (PARAM_SCEV_MAX_EXPR_SIZE))
return fold_build2 (code, type,
fold_convert (type, op0),
fold_convert (op1_type, op1));
else
return chrec_dont_know;
}
}
}
}
/* Fold the addition of two chrecs. */
tree
chrec_fold_plus (tree type,
tree op0,
tree op1)
{
enum tree_code code;
if (automatically_generated_chrec_p (op0)
|| automatically_generated_chrec_p (op1))
return chrec_fold_automatically_generated_operands (op0, op1);
if (integer_zerop (op0))
return chrec_convert (type, op1, NULL);
if (integer_zerop (op1))
return chrec_convert (type, op0, NULL);
if (POINTER_TYPE_P (type))
code = POINTER_PLUS_EXPR;
else
code = PLUS_EXPR;
return chrec_fold_plus_1 (code, type, op0, op1);
}
/* Fold the subtraction of two chrecs. */
tree
chrec_fold_minus (tree type,
tree op0,
tree op1)
{
if (automatically_generated_chrec_p (op0)
|| automatically_generated_chrec_p (op1))
return chrec_fold_automatically_generated_operands (op0, op1);
if (integer_zerop (op1))
return op0;
return chrec_fold_plus_1 (MINUS_EXPR, type, op0, op1);
}
/* Fold the multiplication of two chrecs. */
tree
chrec_fold_multiply (tree type,
tree op0,
tree op1)
{
if (automatically_generated_chrec_p (op0)
|| automatically_generated_chrec_p (op1))
return chrec_fold_automatically_generated_operands (op0, op1);
switch (TREE_CODE (op0))
{
case POLYNOMIAL_CHREC:
switch (TREE_CODE (op1))
{
case POLYNOMIAL_CHREC:
return chrec_fold_multiply_poly_poly (type, op0, op1);
default:
if (integer_onep (op1))
return op0;
if (integer_zerop (op1))
return build_int_cst (type, 0);
return build_polynomial_chrec
(CHREC_VARIABLE (op0),
chrec_fold_multiply (type, CHREC_LEFT (op0), op1),
chrec_fold_multiply (type, CHREC_RIGHT (op0), op1));
}
default:
if (integer_onep (op0))
return op1;
if (integer_zerop (op0))
return build_int_cst (type, 0);
switch (TREE_CODE (op1))
{
case POLYNOMIAL_CHREC:
return build_polynomial_chrec
(CHREC_VARIABLE (op1),
chrec_fold_multiply (type, CHREC_LEFT (op1), op0),
chrec_fold_multiply (type, CHREC_RIGHT (op1), op0));
default:
if (integer_onep (op1))
return op0;
if (integer_zerop (op1))
return build_int_cst (type, 0);
return fold_build2 (MULT_EXPR, type, op0, op1);
}
}
}
/* Operations. */
/* Evaluate the binomial coefficient. Return NULL_TREE if the intermediate
calculation overflows, otherwise return C(n,k) with type TYPE. */
static tree
tree_fold_binomial (tree type, tree n, unsigned int k)
{
unsigned HOST_WIDE_INT lidx, lnum, ldenom, lres, ldum;
HOST_WIDE_INT hidx, hnum, hdenom, hres, hdum;
unsigned int i;
tree res;
/* Handle the most frequent cases. */
if (k == 0)
return build_int_cst (type, 1);
if (k == 1)
return fold_convert (type, n);
/* Check that k <= n. */
if (TREE_INT_CST_HIGH (n) == 0
&& TREE_INT_CST_LOW (n) < k)
return NULL_TREE;
/* Numerator = n. */
lnum = TREE_INT_CST_LOW (n);
hnum = TREE_INT_CST_HIGH (n);
/* Denominator = 2. */
ldenom = 2;
hdenom = 0;
/* Index = Numerator-1. */
if (lnum == 0)
{
hidx = hnum - 1;
lidx = ~ (unsigned HOST_WIDE_INT) 0;
}
else
{
hidx = hnum;
lidx = lnum - 1;
}
/* Numerator = Numerator*Index = n*(n-1). */
if (mul_double (lnum, hnum, lidx, hidx, &lnum, &hnum))
return NULL_TREE;
for (i = 3; i <= k; i++)
{
/* Index--. */
if (lidx == 0)
{
hidx--;
lidx = ~ (unsigned HOST_WIDE_INT) 0;
}
else
lidx--;
/* Numerator *= Index. */
if (mul_double (lnum, hnum, lidx, hidx, &lnum, &hnum))
return NULL_TREE;
/* Denominator *= i. */
mul_double (ldenom, hdenom, i, 0, &ldenom, &hdenom);
}
/* Result = Numerator / Denominator. */
div_and_round_double (EXACT_DIV_EXPR, 1, lnum, hnum, ldenom, hdenom,
&lres, &hres, &ldum, &hdum);
res = build_int_cst_wide (type, lres, hres);
return int_fits_type_p (res, type) ? res : NULL_TREE;
}
/* Helper function. Use the Newton's interpolating formula for
evaluating the value of the evolution function. */
static tree
chrec_evaluate (unsigned var, tree chrec, tree n, unsigned int k)
{
tree arg0, arg1, binomial_n_k;
tree type = TREE_TYPE (chrec);
struct loop *var_loop = get_loop (var);
while (TREE_CODE (chrec) == POLYNOMIAL_CHREC
&& flow_loop_nested_p (var_loop, get_chrec_loop (chrec)))
chrec = CHREC_LEFT (chrec);
if (TREE_CODE (chrec) == POLYNOMIAL_CHREC
&& CHREC_VARIABLE (chrec) == var)
{
arg1 = chrec_evaluate (var, CHREC_RIGHT (chrec), n, k + 1);
if (arg1 == chrec_dont_know)
return chrec_dont_know;
binomial_n_k = tree_fold_binomial (type, n, k);
if (!binomial_n_k)
return chrec_dont_know;
arg0 = fold_build2 (MULT_EXPR, type,
CHREC_LEFT (chrec), binomial_n_k);
return chrec_fold_plus (type, arg0, arg1);
}
binomial_n_k = tree_fold_binomial (type, n, k);
if (!binomial_n_k)
return chrec_dont_know;
return fold_build2 (MULT_EXPR, type, chrec, binomial_n_k);
}
/* Evaluates "CHREC (X)" when the varying variable is VAR.
Example: Given the following parameters,
var = 1
chrec = {3, +, 4}_1
x = 10
The result is given by the Newton's interpolating formula:
3 * \binom{10}{0} + 4 * \binom{10}{1}.
*/
tree
chrec_apply (unsigned var,
tree chrec,
tree x)
{
tree type = chrec_type (chrec);
tree res = chrec_dont_know;
if (automatically_generated_chrec_p (chrec)
|| automatically_generated_chrec_p (x)
/* When the symbols are defined in an outer loop, it is possible
to symbolically compute the apply, since the symbols are
constants with respect to the varying loop. */
|| chrec_contains_symbols_defined_in_loop (chrec, var))
return chrec_dont_know;
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, "(chrec_apply \n");
if (TREE_CODE (x) == INTEGER_CST && SCALAR_FLOAT_TYPE_P (type))
x = build_real_from_int_cst (type, x);
if (evolution_function_is_affine_p (chrec))
{
/* "{a, +, b} (x)" -> "a + b*x". */
x = chrec_convert_rhs (type, x, NULL);
res = chrec_fold_multiply (TREE_TYPE (x), CHREC_RIGHT (chrec), x);
res = chrec_fold_plus (type, CHREC_LEFT (chrec), res);
}
else if (TREE_CODE (chrec) != POLYNOMIAL_CHREC)
res = chrec;
else if (TREE_CODE (x) == INTEGER_CST
&& tree_int_cst_sgn (x) == 1)
/* testsuite/.../ssa-chrec-38.c. */
res = chrec_evaluate (var, chrec, x, 0);
else
res = chrec_dont_know;
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, " (varying_loop = %d\n", var);
fprintf (dump_file, ")\n (chrec = ");
print_generic_expr (dump_file, chrec, 0);
fprintf (dump_file, ")\n (x = ");
print_generic_expr (dump_file, x, 0);
fprintf (dump_file, ")\n (res = ");
print_generic_expr (dump_file, res, 0);
fprintf (dump_file, "))\n");
}
return res;
}
/* Replaces the initial condition in CHREC with INIT_COND. */
tree
chrec_replace_initial_condition (tree chrec,
tree init_cond)
{
if (automatically_generated_chrec_p (chrec))
return chrec;
gcc_assert (chrec_type (chrec) == chrec_type (init_cond));
switch (TREE_CODE (chrec))
{
case POLYNOMIAL_CHREC:
return build_polynomial_chrec
(CHREC_VARIABLE (chrec),
chrec_replace_initial_condition (CHREC_LEFT (chrec), init_cond),
CHREC_RIGHT (chrec));
default:
return init_cond;
}
}
/* Returns the initial condition of a given CHREC. */
tree
initial_condition (tree chrec)
{
if (automatically_generated_chrec_p (chrec))
return chrec;
if (TREE_CODE (chrec) == POLYNOMIAL_CHREC)
return initial_condition (CHREC_LEFT (chrec));
else
return chrec;
}
/* Returns a univariate function that represents the evolution in
LOOP_NUM. Mask the evolution of any other loop. */
tree
hide_evolution_in_other_loops_than_loop (tree chrec,
unsigned loop_num)
{
struct loop *loop = get_loop (loop_num), *chloop;
if (automatically_generated_chrec_p (chrec))
return chrec;
switch (TREE_CODE (chrec))
{
case POLYNOMIAL_CHREC:
chloop = get_chrec_loop (chrec);
if (chloop == loop)
return build_polynomial_chrec
(loop_num,
hide_evolution_in_other_loops_than_loop (CHREC_LEFT (chrec),
loop_num),
CHREC_RIGHT (chrec));
else if (flow_loop_nested_p (chloop, loop))
/* There is no evolution in this loop. */
return initial_condition (chrec);
else
{
gcc_assert (flow_loop_nested_p (loop, chloop));
return hide_evolution_in_other_loops_than_loop (CHREC_LEFT (chrec),
loop_num);
}
default:
return chrec;
}
}
/* Returns the evolution part of CHREC in LOOP_NUM when RIGHT is
true, otherwise returns the initial condition in LOOP_NUM. */
static tree
chrec_component_in_loop_num (tree chrec,
unsigned loop_num,
bool right)
{
tree component;
struct loop *loop = get_loop (loop_num), *chloop;
if (automatically_generated_chrec_p (chrec))
return chrec;
switch (TREE_CODE (chrec))
{
case POLYNOMIAL_CHREC:
chloop = get_chrec_loop (chrec);
if (chloop == loop)
{
if (right)
component = CHREC_RIGHT (chrec);
else
component = CHREC_LEFT (chrec);
if (TREE_CODE (CHREC_LEFT (chrec)) != POLYNOMIAL_CHREC
|| CHREC_VARIABLE (CHREC_LEFT (chrec)) != CHREC_VARIABLE (chrec))
return component;
else
return build_polynomial_chrec
(loop_num,
chrec_component_in_loop_num (CHREC_LEFT (chrec),
loop_num,
right),
component);
}
else if (flow_loop_nested_p (chloop, loop))
/* There is no evolution part in this loop. */
return NULL_TREE;
else
{
gcc_assert (flow_loop_nested_p (loop, chloop));
return chrec_component_in_loop_num (CHREC_LEFT (chrec),
loop_num,
right);
}
default:
if (right)
return NULL_TREE;
else
return chrec;
}
}
/* Returns the evolution part in LOOP_NUM. Example: the call
evolution_part_in_loop_num ({{0, +, 1}_1, +, 2}_1, 1) returns
{1, +, 2}_1 */
tree
evolution_part_in_loop_num (tree chrec,
unsigned loop_num)
{
return chrec_component_in_loop_num (chrec, loop_num, true);
}
/* Returns the initial condition in LOOP_NUM. Example: the call
initial_condition_in_loop_num ({{0, +, 1}_1, +, 2}_2, 2) returns
{0, +, 1}_1 */
tree
initial_condition_in_loop_num (tree chrec,
unsigned loop_num)
{
return chrec_component_in_loop_num (chrec, loop_num, false);
}
/* Set or reset the evolution of CHREC to NEW_EVOL in loop LOOP_NUM.
This function is essentially used for setting the evolution to
chrec_dont_know, for example after having determined that it is
impossible to say how many times a loop will execute. */
tree
reset_evolution_in_loop (unsigned loop_num,
tree chrec,
tree new_evol)
{
struct loop *loop = get_loop (loop_num);
if (POINTER_TYPE_P (chrec_type (chrec)))
gcc_assert (sizetype == chrec_type (new_evol));
else
gcc_assert (chrec_type (chrec) == chrec_type (new_evol));
if (TREE_CODE (chrec) == POLYNOMIAL_CHREC
&& flow_loop_nested_p (loop, get_chrec_loop (chrec)))
{
tree left = reset_evolution_in_loop (loop_num, CHREC_LEFT (chrec),
new_evol);
tree right = reset_evolution_in_loop (loop_num, CHREC_RIGHT (chrec),
new_evol);
return build3 (POLYNOMIAL_CHREC, TREE_TYPE (left),
build_int_cst (NULL_TREE, CHREC_VARIABLE (chrec)),
left, right);
}
while (TREE_CODE (chrec) == POLYNOMIAL_CHREC
&& CHREC_VARIABLE (chrec) == loop_num)
chrec = CHREC_LEFT (chrec);
return build_polynomial_chrec (loop_num, chrec, new_evol);
}
/* Merges two evolution functions that were found by following two
alternate paths of a conditional expression. */
tree
chrec_merge (tree chrec1,
tree chrec2)
{
if (chrec1 == chrec_dont_know
|| chrec2 == chrec_dont_know)
return chrec_dont_know;
if (chrec1 == chrec_known
|| chrec2 == chrec_known)
return chrec_known;
if (chrec1 == chrec_not_analyzed_yet)
return chrec2;
if (chrec2 == chrec_not_analyzed_yet)
return chrec1;
if (eq_evolutions_p (chrec1, chrec2))
return chrec1;
return chrec_dont_know;
}
/* Observers. */
/* Helper function for is_multivariate_chrec. */
static bool
is_multivariate_chrec_rec (const_tree chrec, unsigned int rec_var)
{
if (chrec == NULL_TREE)
return false;
if (TREE_CODE (chrec) == POLYNOMIAL_CHREC)
{
if (CHREC_VARIABLE (chrec) != rec_var)
return true;
else
return (is_multivariate_chrec_rec (CHREC_LEFT (chrec), rec_var)
|| is_multivariate_chrec_rec (CHREC_RIGHT (chrec), rec_var));
}
else
return false;
}
/* Determine whether the given chrec is multivariate or not. */
bool
is_multivariate_chrec (const_tree chrec)
{
if (chrec == NULL_TREE)
return false;
if (TREE_CODE (chrec) == POLYNOMIAL_CHREC)
return (is_multivariate_chrec_rec (CHREC_LEFT (chrec),
CHREC_VARIABLE (chrec))
|| is_multivariate_chrec_rec (CHREC_RIGHT (chrec),
CHREC_VARIABLE (chrec)));
else
return false;
}
/* Determines whether the chrec contains symbolic names or not. */
bool
chrec_contains_symbols (const_tree chrec)
{
int i, n;
if (chrec == NULL_TREE)
return false;
if (TREE_CODE (chrec) == SSA_NAME
|| TREE_CODE (chrec) == VAR_DECL
|| TREE_CODE (chrec) == PARM_DECL
|| TREE_CODE (chrec) == FUNCTION_DECL
|| TREE_CODE (chrec) == LABEL_DECL
|| TREE_CODE (chrec) == RESULT_DECL
|| TREE_CODE (chrec) == FIELD_DECL)
return true;
n = TREE_OPERAND_LENGTH (chrec);
for (i = 0; i < n; i++)
if (chrec_contains_symbols (TREE_OPERAND (chrec, i)))
return true;
return false;
}
/* Determines whether the chrec contains undetermined coefficients. */
bool
chrec_contains_undetermined (const_tree chrec)
{
int i, n;
if (chrec == chrec_dont_know)
return true;
if (chrec == NULL_TREE)
return false;
n = TREE_OPERAND_LENGTH (chrec);
for (i = 0; i < n; i++)
if (chrec_contains_undetermined (TREE_OPERAND (chrec, i)))
return true;
return false;
}
/* Determines whether the tree EXPR contains chrecs, and increment
SIZE if it is not a NULL pointer by an estimation of the depth of
the tree. */
bool
tree_contains_chrecs (const_tree expr, int *size)
{
int i, n;
if (expr == NULL_TREE)
return false;
if (size)
(*size)++;
if (tree_is_chrec (expr))
return true;
n = TREE_OPERAND_LENGTH (expr);
for (i = 0; i < n; i++)
if (tree_contains_chrecs (TREE_OPERAND (expr, i), size))
return true;
return false;
}
/* Recursive helper function. */
static bool
evolution_function_is_invariant_rec_p (tree chrec, int loopnum)
{
if (evolution_function_is_constant_p (chrec))
return true;
if (TREE_CODE (chrec) == SSA_NAME
&& (loopnum == 0
|| expr_invariant_in_loop_p (get_loop (loopnum), chrec)))
return true;
if (TREE_CODE (chrec) == POLYNOMIAL_CHREC)
{
if (CHREC_VARIABLE (chrec) == (unsigned) loopnum
|| !evolution_function_is_invariant_rec_p (CHREC_RIGHT (chrec),
loopnum)
|| !evolution_function_is_invariant_rec_p (CHREC_LEFT (chrec),
loopnum))
return false;
return true;
}
switch (TREE_OPERAND_LENGTH (chrec))
{
case 2:
if (!evolution_function_is_invariant_rec_p (TREE_OPERAND (chrec, 1),
loopnum))
return false;
case 1:
if (!evolution_function_is_invariant_rec_p (TREE_OPERAND (chrec, 0),
loopnum))
return false;
return true;
default:
return false;
}
return false;
}
/* Return true if CHREC is invariant in loop LOOPNUM, false otherwise. */
bool
evolution_function_is_invariant_p (tree chrec, int loopnum)
{
return evolution_function_is_invariant_rec_p (chrec, loopnum);
}
/* Determine whether the given tree is an affine multivariate
evolution. */
bool
evolution_function_is_affine_multivariate_p (const_tree chrec, int loopnum)
{