/* Chains of recurrences.
- Copyright (C) 2003, 2004, 2005 Free Software Foundation, Inc.
- Contributed by Sebastian Pop <s.pop@laposte.net>
+ 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 2, or (at your option) any later
+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
for more details.
You should have received a copy of the GNU General Public License
-along with GCC; see the file COPYING. If not, write to the Free
-Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
-02110-1301, USA. */
+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
#include "tree.h"
#include "real.h"
#include "diagnostic.h"
-#include "varray.h"
#include "cfgloop.h"
#include "tree-flow.h"
#include "tree-chrec.h"
/* Determines whether CST is not a constant evolution. */
static inline bool
-is_not_constant_evolution (tree cst)
+is_not_constant_evolution (const_tree cst)
{
return (TREE_CODE (cst) == POLYNOMIAL_CHREC);
}
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:
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 (CHREC_VARIABLE (poly0) < CHREC_VARIABLE (poly1))
+ if (flow_loop_nested_p (loop0, loop1))
{
- if (code == PLUS_EXPR)
+ if (code == PLUS_EXPR || code == POINTER_PLUS_EXPR)
return build_polynomial_chrec
(CHREC_VARIABLE (poly1),
chrec_fold_plus (type, poly0, CHREC_LEFT (poly1)),
: build_int_cst_type (type, -1)));
}
- if (CHREC_VARIABLE (poly0) > CHREC_VARIABLE (poly1))
+ if (flow_loop_nested_p (loop1, loop0))
{
- if (code == PLUS_EXPR)
+ if (code == PLUS_EXPR || code == POINTER_PLUS_EXPR)
return build_polynomial_chrec
(CHREC_VARIABLE (poly0),
chrec_fold_plus (type, CHREC_LEFT (poly0), poly1),
chrec_fold_minus (type, CHREC_LEFT (poly0), poly1),
CHREC_RIGHT (poly0));
}
-
- if (code == PLUS_EXPR)
+
+ /* 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
- (type, CHREC_RIGHT (poly0), CHREC_RIGHT (poly1));
+ (rtype, CHREC_RIGHT (poly0), CHREC_RIGHT (poly1));
}
else
{
{
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 (CHREC_VARIABLE (poly0) < CHREC_VARIABLE (poly1))
+ 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 (CHREC_VARIABLE (poly1) < CHREC_VARIABLE (poly0))
+ 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. */
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 (type, 2), t2);
+ : build_int_cst (type, 2), t2);
var = CHREC_VARIABLE (poly0);
return build_polynomial_chrec (var, t0,
/* Fold the addition of two chrecs. */
static tree
-chrec_fold_plus_1 (enum tree_code code,
- tree type,
- tree op0,
- tree op1)
+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);
return chrec_fold_plus_poly_poly (code, type, op0, op1);
default:
- if (code == PLUS_EXPR)
+ if (code == PLUS_EXPR || code == POINTER_PLUS_EXPR)
return build_polynomial_chrec
(CHREC_VARIABLE (op0),
chrec_fold_plus (type, CHREC_LEFT (op0), op1),
switch (TREE_CODE (op1))
{
case POLYNOMIAL_CHREC:
- if (code == PLUS_EXPR)
+ if (code == PLUS_EXPR || code == POINTER_PLUS_EXPR)
return build_polynomial_chrec
(CHREC_VARIABLE (op1),
chrec_fold_plus (type, op0, CHREC_LEFT (op1)),
else if (size < PARAM_VALUE (PARAM_SCEV_MAX_EXPR_SIZE))
return fold_build2 (code, type,
fold_convert (type, op0),
- fold_convert (type, op1));
+ fold_convert (op1_type, op1));
else
return chrec_dont_know;
}
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 op1;
+ return chrec_convert (type, op1, NULL);
if (integer_zerop (op1))
- return op0;
+ return chrec_convert (type, op0, NULL);
+
+ if (POINTER_TYPE_P (type))
+ code = POINTER_PLUS_EXPR;
+ else
+ code = PLUS_EXPR;
- return chrec_fold_plus_1 (PLUS_EXPR, type, op0, op1);
+ return chrec_fold_plus_1 (code, type, op0, op1);
}
/* Fold the subtraction of two chrecs. */
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;
if (integer_onep (op1))
return op0;
if (integer_zerop (op1))
- return build_int_cst_type (type, 0);
+ return build_int_cst (type, 0);
return build_polynomial_chrec
(CHREC_VARIABLE (op0),
return op1;
if (integer_zerop (op0))
- return build_int_cst_type (type, 0);
+ return build_int_cst (type, 0);
switch (TREE_CODE (op1))
{
if (integer_onep (op1))
return op0;
if (integer_zerop (op1))
- return build_int_cst_type (type, 0);
+ return build_int_cst (type, 0);
return fold_build2 (MULT_EXPR, type, op0, op1);
}
}
{
tree arg0, arg1, binomial_n_k;
tree type = TREE_TYPE (chrec);
+ struct loop *var_loop = get_loop (var);
while (TREE_CODE (chrec) == POLYNOMIAL_CHREC
- && CHREC_VARIABLE (chrec) > var)
+ && flow_loop_nested_p (var_loop, get_chrec_loop (chrec)))
chrec = CHREC_LEFT (chrec);
if (TREE_CODE (chrec) == POLYNOMIAL_CHREC
&& CHREC_VARIABLE (chrec) == var)
{
- arg0 = chrec_evaluate (var, CHREC_RIGHT (chrec), n, k + 1);
- if (arg0 == chrec_dont_know)
+ 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;
- arg1 = fold_build2 (MULT_EXPR, type,
+ arg0 = fold_build2 (MULT_EXPR, type,
CHREC_LEFT (chrec), binomial_n_k);
return chrec_fold_plus (type, arg0, arg1);
}
if (evolution_function_is_affine_p (chrec))
{
/* "{a, +, b} (x)" -> "a + b*x". */
- x = chrec_convert (type, x, NULL_TREE);
- res = chrec_fold_multiply (type, CHREC_RIGHT (chrec), x);
- if (!integer_zerop (CHREC_LEFT (chrec)))
- res = chrec_fold_plus (type, CHREC_LEFT (chrec), res);
+ 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)
{
if (automatically_generated_chrec_p (chrec))
return chrec;
-
+
+ gcc_assert (chrec_type (chrec) == chrec_type (init_cond));
+
switch (TREE_CODE (chrec))
{
case POLYNOMIAL_CHREC:
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:
- if (CHREC_VARIABLE (chrec) == loop_num)
+ 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 (CHREC_VARIABLE (chrec) < loop_num)
+ else if (flow_loop_nested_p (chloop, loop))
/* There is no evolution in this loop. */
return initial_condition (chrec);
else
- return hide_evolution_in_other_loops_than_loop (CHREC_LEFT (chrec),
- loop_num);
+ {
+ gcc_assert (flow_loop_nested_p (loop, chloop));
+ return hide_evolution_in_other_loops_than_loop (CHREC_LEFT (chrec),
+ loop_num);
+ }
default:
return chrec;
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:
- if (CHREC_VARIABLE (chrec) == loop_num)
+ chloop = get_chrec_loop (chrec);
+
+ if (chloop == loop)
{
if (right)
component = CHREC_RIGHT (chrec);
component);
}
- else if (CHREC_VARIABLE (chrec) < loop_num)
+ else if (flow_loop_nested_p (chloop, loop))
/* There is no evolution part in this loop. */
return NULL_TREE;
else
- return chrec_component_in_loop_num (CHREC_LEFT (chrec),
- loop_num,
- right);
+ {
+ gcc_assert (flow_loop_nested_p (loop, chloop));
+ return chrec_component_in_loop_num (CHREC_LEFT (chrec),
+ loop_num,
+ right);
+ }
default:
if (right)
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
- && CHREC_VARIABLE (chrec) > loop_num)
+ && flow_loop_nested_p (loop, get_chrec_loop (chrec)))
{
tree left = reset_evolution_in_loop (loop_num, CHREC_LEFT (chrec),
new_evol);
if (chrec2 == chrec_not_analyzed_yet)
return chrec1;
- if (operand_equal_p (chrec1, chrec2, 0))
+ if (eq_evolutions_p (chrec1, chrec2))
return chrec1;
return chrec_dont_know;
/* Helper function for is_multivariate_chrec. */
static bool
-is_multivariate_chrec_rec (tree chrec, unsigned int rec_var)
+is_multivariate_chrec_rec (const_tree chrec, unsigned int rec_var)
{
if (chrec == NULL_TREE)
return false;
/* Determine whether the given chrec is multivariate or not. */
bool
-is_multivariate_chrec (tree chrec)
+is_multivariate_chrec (const_tree chrec)
{
if (chrec == NULL_TREE)
return false;
/* Determines whether the chrec contains symbolic names or not. */
bool
-chrec_contains_symbols (tree chrec)
+chrec_contains_symbols (const_tree chrec)
{
+ int i, n;
+
if (chrec == NULL_TREE)
return false;
|| TREE_CODE (chrec) == RESULT_DECL
|| TREE_CODE (chrec) == FIELD_DECL)
return true;
-
- switch (TREE_CODE_LENGTH (TREE_CODE (chrec)))
- {
- case 3:
- if (chrec_contains_symbols (TREE_OPERAND (chrec, 2)))
- return true;
-
- case 2:
- if (chrec_contains_symbols (TREE_OPERAND (chrec, 1)))
- return true;
-
- case 1:
- if (chrec_contains_symbols (TREE_OPERAND (chrec, 0)))
- return true;
-
- default:
- return false;
- }
+
+ 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 (tree chrec)
+chrec_contains_undetermined (const_tree chrec)
{
- if (chrec == chrec_dont_know
- || chrec == chrec_not_analyzed_yet
- || chrec == NULL_TREE)
+ int i, n;
+
+ if (chrec == chrec_dont_know)
return true;
-
- switch (TREE_CODE_LENGTH (TREE_CODE (chrec)))
- {
- case 3:
- if (chrec_contains_undetermined (TREE_OPERAND (chrec, 2)))
- return true;
-
- case 2:
- if (chrec_contains_undetermined (TREE_OPERAND (chrec, 1)))
- return true;
-
- case 1:
- if (chrec_contains_undetermined (TREE_OPERAND (chrec, 0)))
- return true;
-
- default:
- return false;
- }
+
+ 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
the tree. */
bool
-tree_contains_chrecs (tree expr, int *size)
+tree_contains_chrecs (const_tree expr, int *size)
{
+ int i, n;
+
if (expr == NULL_TREE)
return false;
if (tree_is_chrec (expr))
return true;
- switch (TREE_CODE_LENGTH (TREE_CODE (expr)))
- {
- case 3:
- if (tree_contains_chrecs (TREE_OPERAND (expr, 2), size))
- return true;
-
- case 2:
- if (tree_contains_chrecs (TREE_OPERAND (expr, 1), size))
- return true;
-
- case 1:
- if (tree_contains_chrecs (TREE_OPERAND (expr, 0), size))
- return true;
-
- default:
- return false;
- }
+ 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. */
if (evolution_function_is_constant_p (chrec))
return true;
- if (TREE_CODE (chrec) == SSA_NAME
- && expr_invariant_in_loop_p (current_loops->parray[loopnum],
- chrec))
+ 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)
return true;
}
- switch (TREE_CODE_LENGTH (TREE_CODE (chrec)))
+ switch (TREE_OPERAND_LENGTH (chrec))
{
case 2:
if (!evolution_function_is_invariant_rec_p (TREE_OPERAND (chrec, 1),
bool
evolution_function_is_invariant_p (tree chrec, int loopnum)
{
- if (evolution_function_is_constant_p (chrec))
- return true;
-
- if (current_loops != NULL)
- return evolution_function_is_invariant_rec_p (chrec, loopnum);
-
- return false;
+ 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 (tree chrec)
+evolution_function_is_affine_multivariate_p (const_tree chrec, int loopnum)
{
if (chrec == NULL_TREE)
return false;
switch (TREE_CODE (chrec))
{
case POLYNOMIAL_CHREC:
- if (evolution_function_is_constant_p (CHREC_LEFT (chrec)))
+ if (evolution_function_is_invariant_rec_p (CHREC_LEFT (chrec), loopnum))
{
- if (evolution_function_is_constant_p (CHREC_RIGHT (chrec)))
+ if (evolution_function_is_invariant_rec_p (CHREC_RIGHT (chrec), loopnum))
return true;
else
{
&& CHREC_VARIABLE (CHREC_RIGHT (chrec))
!= CHREC_VARIABLE (chrec)
&& evolution_function_is_affine_multivariate_p
- (CHREC_RIGHT (chrec)))
+ (CHREC_RIGHT (chrec), loopnum))
return true;
else
return false;
}
else
{
- if (evolution_function_is_constant_p (CHREC_RIGHT (chrec))
+ if (evolution_function_is_invariant_rec_p (CHREC_RIGHT (chrec), loopnum)
&& TREE_CODE (CHREC_LEFT (chrec)) == POLYNOMIAL_CHREC
&& CHREC_VARIABLE (CHREC_LEFT (chrec)) != CHREC_VARIABLE (chrec)
&& evolution_function_is_affine_multivariate_p
- (CHREC_LEFT (chrec)))
+ (CHREC_LEFT (chrec), loopnum))
return true;
else
return false;
variables. */
bool
-evolution_function_is_univariate_p (tree chrec)
+evolution_function_is_univariate_p (const_tree chrec)
{
if (chrec == NULL_TREE)
return true;
}
}
+/* Returns true if TYPE is a type in that we cannot directly perform
+ arithmetics, even though it is a scalar type. */
+
+static bool
+avoid_arithmetics_in_type_p (const_tree type)
+{
+ /* Ada frontend uses subtypes -- an arithmetic cannot be directly performed
+ in the subtype, but a base type must be used, and the result then can
+ be casted to the subtype. */
+ if (TREE_CODE (type) == INTEGER_TYPE && TREE_TYPE (type) != NULL_TREE)
+ return true;
+
+ return false;
+}
+
+static tree chrec_convert_1 (tree, tree, gimple, bool);
+
+/* Converts BASE and STEP of affine scev to TYPE. LOOP is the loop whose iv
+ the scev corresponds to. AT_STMT is the statement at that the scev is
+ evaluated. USE_OVERFLOW_SEMANTICS is true if this function should assume that
+ the rules for overflow of the given language apply (e.g., that signed
+ arithmetics in C does not overflow) -- i.e., to use them to avoid unnecessary
+ tests, but also to enforce that the result follows them. Returns true if the
+ conversion succeeded, false otherwise. */
+
+bool
+convert_affine_scev (struct loop *loop, tree type,
+ tree *base, tree *step, gimple at_stmt,
+ bool use_overflow_semantics)
+{
+ tree ct = TREE_TYPE (*step);
+ bool enforce_overflow_semantics;
+ bool must_check_src_overflow, must_check_rslt_overflow;
+ tree new_base, new_step;
+ tree step_type = POINTER_TYPE_P (type) ? sizetype : type;
+
+ /* If we cannot perform arithmetic in TYPE, avoid creating an scev. */
+ if (avoid_arithmetics_in_type_p (type))
+ return false;
+
+ /* In general,
+ (TYPE) (BASE + STEP * i) = (TYPE) BASE + (TYPE -- sign extend) STEP * i,
+ but we must check some assumptions.
+
+ 1) If [BASE, +, STEP] wraps, the equation is not valid when precision
+ of CT is smaller than the precision of TYPE. For example, when we
+ cast unsigned char [254, +, 1] to unsigned, the values on left side
+ are 254, 255, 0, 1, ..., but those on the right side are
+ 254, 255, 256, 257, ...
+ 2) In case that we must also preserve the fact that signed ivs do not
+ overflow, we must additionally check that the new iv does not wrap.
+ For example, unsigned char [125, +, 1] casted to signed char could
+ become a wrapping variable with values 125, 126, 127, -128, -127, ...,
+ which would confuse optimizers that assume that this does not
+ happen. */
+ must_check_src_overflow = TYPE_PRECISION (ct) < TYPE_PRECISION (type);
+
+ enforce_overflow_semantics = (use_overflow_semantics
+ && nowrap_type_p (type));
+ if (enforce_overflow_semantics)
+ {
+ /* We can avoid checking whether the result overflows in the following
+ cases:
+
+ -- must_check_src_overflow is true, and the range of TYPE is superset
+ of the range of CT -- i.e., in all cases except if CT signed and
+ TYPE unsigned.
+ -- both CT and TYPE have the same precision and signedness, and we
+ verify instead that the source does not overflow (this may be
+ easier than verifying it for the result, as we may use the
+ information about the semantics of overflow in CT). */
+ if (must_check_src_overflow)
+ {
+ if (TYPE_UNSIGNED (type) && !TYPE_UNSIGNED (ct))
+ must_check_rslt_overflow = true;
+ else
+ must_check_rslt_overflow = false;
+ }
+ else if (TYPE_UNSIGNED (ct) == TYPE_UNSIGNED (type)
+ && TYPE_PRECISION (ct) == TYPE_PRECISION (type))
+ {
+ must_check_rslt_overflow = false;
+ must_check_src_overflow = true;
+ }
+ else
+ must_check_rslt_overflow = true;
+ }
+ else
+ must_check_rslt_overflow = false;
+
+ if (must_check_src_overflow
+ && scev_probably_wraps_p (*base, *step, at_stmt, loop,
+ use_overflow_semantics))
+ return false;
+
+ new_base = chrec_convert_1 (type, *base, at_stmt,
+ use_overflow_semantics);
+ /* The step must be sign extended, regardless of the signedness
+ of CT and TYPE. This only needs to be handled specially when
+ CT is unsigned -- to avoid e.g. unsigned char [100, +, 255]
+ (with values 100, 99, 98, ...) from becoming signed or unsigned
+ [100, +, 255] with values 100, 355, ...; the sign-extension is
+ performed by default when CT is signed. */
+ new_step = *step;
+ if (TYPE_PRECISION (step_type) > TYPE_PRECISION (ct) && TYPE_UNSIGNED (ct))
+ new_step = chrec_convert_1 (signed_type_for (ct), new_step, at_stmt,
+ use_overflow_semantics);
+ new_step = chrec_convert_1 (step_type, new_step, at_stmt, use_overflow_semantics);
+
+ if (automatically_generated_chrec_p (new_base)
+ || automatically_generated_chrec_p (new_step))
+ return false;
+
+ if (must_check_rslt_overflow
+ /* Note that in this case we cannot use the fact that signed variables
+ do not overflow, as this is what we are verifying for the new iv. */
+ && scev_probably_wraps_p (new_base, new_step, at_stmt, loop, false))
+ return false;
+
+ *base = new_base;
+ *step = new_step;
+ return true;
+}
\f
+/* Convert CHREC for the right hand side of a CREC.
+ The increment for a pointer type is always sizetype. */
+tree
+chrec_convert_rhs (tree type, tree chrec, gimple at_stmt)
+{
+ if (POINTER_TYPE_P (type))
+ type = sizetype;
+ return chrec_convert (type, chrec, at_stmt);
+}
+
/* Convert CHREC to TYPE. When the analyzer knows the context in
which the CHREC is built, it sets AT_STMT to the statement that
contains the definition of the analyzed variable, otherwise the
*/
tree
-chrec_convert (tree type, tree chrec, tree at_stmt)
+chrec_convert (tree type, tree chrec, gimple at_stmt)
+{
+ return chrec_convert_1 (type, chrec, at_stmt, true);
+}
+
+/* Convert CHREC to TYPE. When the analyzer knows the context in
+ which the CHREC is built, it sets AT_STMT to the statement that
+ contains the definition of the analyzed variable, otherwise the
+ conversion is less accurate: the information is used for
+ determining a more accurate estimation of the number of iterations.
+ By default AT_STMT could be safely set to NULL_TREE.
+
+ USE_OVERFLOW_SEMANTICS is true if this function should assume that
+ the rules for overflow of the given language apply (e.g., that signed
+ arithmetics in C does not overflow) -- i.e., to use them to avoid unnecessary
+ tests, but also to enforce that the result follows them. */
+
+static tree
+chrec_convert_1 (tree type, tree chrec, gimple at_stmt,
+ bool use_overflow_semantics)
{
tree ct, res;
+ tree base, step;
+ struct loop *loop;
if (automatically_generated_chrec_p (chrec))
return chrec;
if (ct == type)
return chrec;
- if (evolution_function_is_affine_p (chrec))
- {
- tree base, step;
- bool dummy;
- struct loop *loop = current_loops->parray[CHREC_VARIABLE (chrec)];
-
- base = instantiate_parameters (loop, CHREC_LEFT (chrec));
- step = instantiate_parameters (loop, CHREC_RIGHT (chrec));
-
- /* Avoid conversion of (signed char) {(uchar)1, +, (uchar)1}_x
- when it is not possible to prove that the scev does not wrap.
- See PR22236, where a sequence 1, 2, ..., 255 has to be
- converted to signed char, but this would wrap:
- 1, 2, ..., 127, -128, ... The result should not be
- {(schar)1, +, (schar)1}_x, but instead, we should keep the
- conversion: (schar) {(uchar)1, +, (uchar)1}_x. */
- if (scev_probably_wraps_p (type, base, step, at_stmt, loop,
- &dummy, &dummy))
- goto failed_to_convert;
-
- step = convert_step (loop, type, base, step, at_stmt);
- if (!step)
- {
- failed_to_convert:;
- if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file, "(failed conversion:");
- fprintf (dump_file, "\n type: ");
- print_generic_expr (dump_file, type, 0);
- fprintf (dump_file, "\n base: ");
- print_generic_expr (dump_file, base, 0);
- fprintf (dump_file, "\n step: ");
- print_generic_expr (dump_file, step, 0);
- fprintf (dump_file, "\n estimated_nb_iterations: ");
- print_generic_expr (dump_file, loop->estimated_nb_iterations, 0);
- fprintf (dump_file, "\n)\n");
- }
+ if (!evolution_function_is_affine_p (chrec))
+ goto keep_cast;
- return fold_convert (type, chrec);
- }
+ loop = get_chrec_loop (chrec);
+ base = CHREC_LEFT (chrec);
+ step = CHREC_RIGHT (chrec);
- return build_polynomial_chrec (CHREC_VARIABLE (chrec),
- chrec_convert (type, CHREC_LEFT (chrec),
- at_stmt),
- step);
- }
-
- if (TREE_CODE (chrec) == POLYNOMIAL_CHREC)
- return chrec_dont_know;
+ if (convert_affine_scev (loop, type, &base, &step, at_stmt,
+ use_overflow_semantics))
+ return build_polynomial_chrec (loop->num, base, step);
+ /* If we cannot propagate the cast inside the chrec, just keep the cast. */
+keep_cast:
res = fold_convert (type, chrec);
/* Don't propagate overflows. */
if (CONSTANT_CLASS_P (res))
- {
- TREE_CONSTANT_OVERFLOW (res) = 0;
- TREE_OVERFLOW (res) = 0;
- }
+ TREE_OVERFLOW (res) = 0;
/* But reject constants that don't fit in their type after conversion.
This can happen if TYPE_MIN_VALUE or TYPE_MAX_VALUE are not the
tree
chrec_convert_aggressive (tree type, tree chrec)
{
- tree inner_type, left, right, lc, rc;
+ tree inner_type, left, right, lc, rc, rtype;
if (automatically_generated_chrec_p (chrec)
|| TREE_CODE (chrec) != POLYNOMIAL_CHREC)
if (TYPE_PRECISION (type) > TYPE_PRECISION (inner_type))
return NULL_TREE;
+ /* If we cannot perform arithmetic in TYPE, avoid creating an scev. */
+ if (avoid_arithmetics_in_type_p (type))
+ return NULL_TREE;
+
+ rtype = POINTER_TYPE_P (type) ? sizetype : type;
+
left = CHREC_LEFT (chrec);
right = CHREC_RIGHT (chrec);
lc = chrec_convert_aggressive (type, left);
if (!lc)
- lc = chrec_convert (type, left, NULL_TREE);
- rc = chrec_convert_aggressive (type, right);
+ lc = chrec_convert (type, left, NULL);
+ rc = chrec_convert_aggressive (rtype, right);
if (!rc)
- rc = chrec_convert (type, right, NULL_TREE);
-
+ rc = chrec_convert (rtype, right, NULL);
+
return build_polynomial_chrec (CHREC_VARIABLE (chrec), lc, rc);
}
-/* Returns the type of the chrec. */
+/* Returns true when CHREC0 == CHREC1. */
-tree
-chrec_type (tree chrec)
+bool
+eq_evolutions_p (const_tree chrec0, const_tree chrec1)
{
- if (automatically_generated_chrec_p (chrec))
- return NULL_TREE;
-
- return TREE_TYPE (chrec);
+ if (chrec0 == NULL_TREE
+ || chrec1 == NULL_TREE
+ || TREE_CODE (chrec0) != TREE_CODE (chrec1))
+ return false;
+
+ if (chrec0 == chrec1)
+ return true;
+
+ switch (TREE_CODE (chrec0))
+ {
+ case INTEGER_CST:
+ return operand_equal_p (chrec0, chrec1, 0);
+
+ case POLYNOMIAL_CHREC:
+ return (CHREC_VARIABLE (chrec0) == CHREC_VARIABLE (chrec1)
+ && eq_evolutions_p (CHREC_LEFT (chrec0), CHREC_LEFT (chrec1))
+ && eq_evolutions_p (CHREC_RIGHT (chrec0), CHREC_RIGHT (chrec1)));
+ default:
+ return false;
+ }
+}
+
+/* Returns EV_GROWS if CHREC grows (assuming that it does not overflow),
+ EV_DECREASES if it decreases, and EV_UNKNOWN if we cannot determine
+ which of these cases happens. */
+
+enum ev_direction
+scev_direction (const_tree chrec)
+{
+ const_tree step;
+
+ if (!evolution_function_is_affine_p (chrec))
+ return EV_DIR_UNKNOWN;
+
+ step = CHREC_RIGHT (chrec);
+ if (TREE_CODE (step) != INTEGER_CST)
+ return EV_DIR_UNKNOWN;
+
+ if (tree_int_cst_sign_bit (step))
+ return EV_DIR_DECREASES;
+ else
+ return EV_DIR_GROWS;
+}
+
+/* Iterates over all the components of SCEV, and calls CBCK. */
+
+void
+for_each_scev_op (tree *scev, bool (*cbck) (tree *, void *), void *data)
+{
+ switch (TREE_CODE_LENGTH (TREE_CODE (*scev)))
+ {
+ case 3:
+ for_each_scev_op (&TREE_OPERAND (*scev, 2), cbck, data);
+
+ case 2:
+ for_each_scev_op (&TREE_OPERAND (*scev, 1), cbck, data);
+
+ case 1:
+ for_each_scev_op (&TREE_OPERAND (*scev, 0), cbck, data);
+
+ default:
+ cbck (scev, data);
+ break;
+ }
+}
+
+/* Returns true when the operation can be part of a linear
+ expression. */
+
+static inline bool
+operator_is_linear (tree scev)
+{
+ switch (TREE_CODE (scev))
+ {
+ case INTEGER_CST:
+ case POLYNOMIAL_CHREC:
+ case PLUS_EXPR:
+ case POINTER_PLUS_EXPR:
+ case MULT_EXPR:
+ case MINUS_EXPR:
+ case NEGATE_EXPR:
+ case SSA_NAME:
+ case NON_LVALUE_EXPR:
+ CASE_CONVERT:
+ return true;
+
+ default:
+ return false;
+ }
+}
+
+/* Return true when SCEV is a linear expression. Linear expressions
+ can contain additions, substractions and multiplications.
+ Multiplications are restricted to constant scaling: "cst * x". */
+
+bool
+scev_is_linear_expression (tree scev)
+{
+ if (scev == NULL
+ || !operator_is_linear (scev))
+ return false;
+
+ if (TREE_CODE (scev) == MULT_EXPR)
+ return !(tree_contains_chrecs (TREE_OPERAND (scev, 0), NULL)
+ && tree_contains_chrecs (TREE_OPERAND (scev, 1), NULL));
+
+ switch (TREE_CODE_LENGTH (TREE_CODE (scev)))
+ {
+ case 3:
+ return scev_is_linear_expression (TREE_OPERAND (scev, 0))
+ && scev_is_linear_expression (TREE_OPERAND (scev, 1))
+ && scev_is_linear_expression (TREE_OPERAND (scev, 2));
+
+ case 2:
+ return scev_is_linear_expression (TREE_OPERAND (scev, 0))
+ && scev_is_linear_expression (TREE_OPERAND (scev, 1));
+
+ case 1:
+ return scev_is_linear_expression (TREE_OPERAND (scev, 0));
+
+ case 0:
+ return true;
+
+ default:
+ return false;
+ }
}
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