/* Functions to determine/estimate number of iterations of a loop.
- Copyright (C) 2004, 2005, 2006, 2007 Free Software Foundation, Inc.
+ Copyright (C) 2004, 2005, 2006, 2007, 2008 Free Software Foundation,
+ Inc.
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
+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
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/>. */
#include "config.h"
#include "system.h"
#include "tree-inline.h"
#include "gmp.h"
-#define SWAP(X, Y) do { void *tmp = (X); (X) = (Y); (Y) = tmp; } while (0)
+#define SWAP(X, Y) do { affine_iv *tmp = (X); (X) = (Y); (Y) = tmp; } while (0)
/* The maximum number of dominator BBs we search for conditions
of loop header copies we use for simplifying a conditional
mpz_t below, up;
} bounds;
-/* Sets RESULT to VAL, taken unsigned if UNS is true and as signed
- otherwise. */
-
-static void
-mpz_set_double_int (mpz_t result, double_int val, bool uns)
-{
- bool negate = false;
- unsigned HOST_WIDE_INT vp[2];
-
- if (!uns && double_int_negative_p (val))
- {
- negate = true;
- val = double_int_neg (val);
- }
-
- vp[0] = val.low;
- vp[1] = (unsigned HOST_WIDE_INT) val.high;
- mpz_import (result, 2, -1, sizeof (HOST_WIDE_INT), 0, 0, vp);
-
- if (negate)
- mpz_neg (result, result);
-}
-
-/* Stores bounds of TYPE to MIN and MAX. */
-
-static void
-get_type_bounds (tree type, mpz_t min, mpz_t max)
-{
- if (TYPE_UNSIGNED (type))
- {
- mpz_set_ui (min, 0);
- mpz_set_double_int (max, double_int_mask (TYPE_PRECISION (type)), true);
- }
- else
- {
- double_int mx, mn;
-
- mx = double_int_mask (TYPE_PRECISION (type) - 1);
- mn = double_int_sext (double_int_add (mx, double_int_one),
- TYPE_PRECISION (type));
- mpz_set_double_int (max, mx, true);
- mpz_set_double_int (min, mn, false);
- }
-}
-
-/* Returns VAL converted to TYPE. If VAL does not fit in TYPE,
- the minimum or maximum value of the type is returned instead. */
-
-static double_int
-mpz_to_double_int (tree type, mpz_t val)
-{
- mpz_t min, max;
- unsigned HOST_WIDE_INT vp[2];
- bool negate = false;
- size_t count;
- double_int res;
-
- mpz_init (min);
- mpz_init (max);
- get_type_bounds (type, min, max);
-
- if (mpz_cmp (val, min) < 0)
- mpz_set (val, min);
- else if (mpz_cmp (val, max) > 0)
- mpz_set (val, max);
-
- if (mpz_sgn (val) < 0)
- negate = true;
-
- vp[0] = 0;
- vp[1] = 0;
- mpz_export (vp, &count, -1, sizeof (HOST_WIDE_INT), 0, 0, val);
- gcc_assert (count <= 2);
-
- mpz_clear (min);
- mpz_clear (max);
-
- res.low = vp[0];
- res.high = (HOST_WIDE_INT) vp[1];
-
- res = double_int_ext (res, TYPE_PRECISION (type), TYPE_UNSIGNED (type));
- if (negate)
- res = double_int_neg (res);
-
- return res;
-}
/* Splits expression EXPR to a variable part VAR and constant OFFSET. */
/* Fallthru. */
case PLUS_EXPR:
+ case POINTER_PLUS_EXPR:
op0 = TREE_OPERAND (expr, 0);
op1 = TREE_OPERAND (expr, 1);
/* If the computation may wrap, we know nothing about the value, except for
the range of the type. */
- get_type_bounds (type, min, max);
+ get_type_static_bounds (type, min, max);
if (!nowrap_type_p (type))
return;
STRIP_SIGN_NOPS (c0);
STRIP_SIGN_NOPS (c1);
ctype = TREE_TYPE (c0);
- if (!tree_ssa_useless_type_conversion_1 (ctype, type))
+ if (!useless_type_conversion_p (ctype, type))
return;
break;
int cnt = 0;
edge e;
basic_block bb;
- tree cond, c0, c1;
+ tree c0, c1;
+ gimple cond;
enum tree_code cmp;
/* Get rid of unnecessary casts, but preserve the value of
if (!(e->flags & (EDGE_TRUE_VALUE | EDGE_FALSE_VALUE)))
continue;
- cond = COND_EXPR_COND (last_stmt (e->src));
- if (!COMPARISON_CLASS_P (cond))
- continue;
- c0 = TREE_OPERAND (cond, 0);
- cmp = TREE_CODE (cond);
- c1 = TREE_OPERAND (cond, 1);
+ cond = last_stmt (e->src);
+ c0 = gimple_cond_lhs (cond);
+ cmp = gimple_cond_code (cond);
+ c1 = gimple_cond_rhs (cond);
if (e->flags & EDGE_FALSE_VALUE)
cmp = invert_tree_comparison (cmp, false);
}
/* Derives the upper bound BND on the number of executions of loop with exit
- condition S * i <> C, assuming that the loop is not infinite. If
+ condition S * i <> C, assuming that this exit is taken. If
NO_OVERFLOW is true, then the control variable of the loop does not
overflow. If NO_OVERFLOW is true or BNDS.below >= 0, then BNDS.up
contains the upper bound on the value of C. */
/* Determines number of iterations of loop whose ending condition
is IV <> FINAL. TYPE is the type of the iv. The number of
- iterations is stored to NITER. NEVER_INFINITE is true if
+ iterations is stored to NITER. EXIT_MUST_BE_TAKEN is true if
we know that the exit must be taken eventually, i.e., that the IV
ever reaches the value FINAL (we derived this earlier, and possibly set
NITER->assumptions to make sure this is the case). BNDS contains the
static bool
number_of_iterations_ne (tree type, affine_iv *iv, tree final,
- struct tree_niter_desc *niter, bool never_infinite,
+ struct tree_niter_desc *niter, bool exit_must_be_taken,
bounds *bnds)
{
tree niter_type = unsigned_type_for (type);
mpz_init (max);
number_of_iterations_ne_max (max, iv->no_overflow, c, s, bnds);
- niter->max = mpz_to_double_int (niter_type, max);
+ niter->max = mpz_get_double_int (niter_type, max, false);
mpz_clear (max);
/* First the trivial cases -- when the step is 1. */
build_int_cst (niter_type, 1), bits);
s = fold_binary_to_constant (RSHIFT_EXPR, niter_type, s, bits);
- if (!never_infinite)
+ if (!exit_must_be_taken)
{
- /* If we cannot assume that the loop is not infinite, record the
+ /* If we cannot assume that the exit is taken eventually, record the
assumptions for divisibility of c. */
assumption = fold_build2 (FLOOR_MOD_EXPR, niter_type, c, d);
assumption = fold_build2 (EQ_EXPR, boolean_type_node,
of the final value does not overflow are recorded in NITER. If we
find the final value, we adjust DELTA and return TRUE. Otherwise
we return false. BNDS bounds the value of IV1->base - IV0->base,
- and will be updated by the same amount as DELTA. */
+ and will be updated by the same amount as DELTA. EXIT_MUST_BE_TAKEN is
+ true if we know that the exit must be taken eventually. */
static bool
number_of_iterations_lt_to_ne (tree type, affine_iv *iv0, affine_iv *iv1,
struct tree_niter_desc *niter,
tree *delta, tree step,
- bounds *bnds)
+ bool exit_must_be_taken, bounds *bnds)
{
tree niter_type = TREE_TYPE (step);
tree mod = fold_build2 (FLOOR_MOD_EXPR, niter_type, *delta, step);
tree tmod;
mpz_t mmod;
tree assumption = boolean_true_node, bound, noloop;
- bool ret = false;
+ bool ret = false, fv_comp_no_overflow;
+ tree type1 = type;
+ if (POINTER_TYPE_P (type))
+ type1 = sizetype;
if (TREE_CODE (mod) != INTEGER_CST)
return false;
if (integer_nonzerop (mod))
mod = fold_build2 (MINUS_EXPR, niter_type, step, mod);
- tmod = fold_convert (type, mod);
+ tmod = fold_convert (type1, mod);
mpz_init (mmod);
mpz_set_double_int (mmod, tree_to_double_int (mod), true);
mpz_neg (mmod, mmod);
+ /* If the induction variable does not overflow and the exit is taken,
+ then the computation of the final value does not overflow. This is
+ also obviously the case if the new final value is equal to the
+ current one. Finally, we postulate this for pointer type variables,
+ as the code cannot rely on the object to that the pointer points being
+ placed at the end of the address space (and more pragmatically,
+ TYPE_{MIN,MAX}_VALUE is not defined for pointers). */
+ if (integer_zerop (mod) || POINTER_TYPE_P (type))
+ fv_comp_no_overflow = true;
+ else if (!exit_must_be_taken)
+ fv_comp_no_overflow = false;
+ else
+ fv_comp_no_overflow =
+ (iv0->no_overflow && integer_nonzerop (iv0->step))
+ || (iv1->no_overflow && integer_nonzerop (iv1->step));
+
if (integer_nonzerop (iv0->step))
{
/* The final value of the iv is iv1->base + MOD, assuming that this
computation does not overflow, and that
iv0->base <= iv1->base + MOD. */
- if (!iv1->no_overflow && !integer_zerop (mod))
+ if (!fv_comp_no_overflow)
{
- bound = fold_build2 (MINUS_EXPR, type,
- TYPE_MAX_VALUE (type), tmod);
+ bound = fold_build2 (MINUS_EXPR, type1,
+ TYPE_MAX_VALUE (type1), tmod);
assumption = fold_build2 (LE_EXPR, boolean_type_node,
iv1->base, bound);
if (integer_zerop (assumption))
}
if (mpz_cmp (mmod, bnds->below) < 0)
noloop = boolean_false_node;
+ else if (POINTER_TYPE_P (type))
+ noloop = fold_build2 (GT_EXPR, boolean_type_node,
+ iv0->base,
+ fold_build2 (POINTER_PLUS_EXPR, type,
+ iv1->base, tmod));
else
noloop = fold_build2 (GT_EXPR, boolean_type_node,
iv0->base,
- fold_build2 (PLUS_EXPR, type,
+ fold_build2 (PLUS_EXPR, type1,
iv1->base, tmod));
}
else
/* The final value of the iv is iv0->base - MOD, assuming that this
computation does not overflow, and that
iv0->base - MOD <= iv1->base. */
- if (!iv0->no_overflow && !integer_zerop (mod))
+ if (!fv_comp_no_overflow)
{
- bound = fold_build2 (PLUS_EXPR, type,
- TYPE_MIN_VALUE (type), tmod);
+ bound = fold_build2 (PLUS_EXPR, type1,
+ TYPE_MIN_VALUE (type1), tmod);
assumption = fold_build2 (GE_EXPR, boolean_type_node,
iv0->base, bound);
if (integer_zerop (assumption))
}
if (mpz_cmp (mmod, bnds->below) < 0)
noloop = boolean_false_node;
+ else if (POINTER_TYPE_P (type))
+ noloop = fold_build2 (GT_EXPR, boolean_type_node,
+ fold_build2 (POINTER_PLUS_EXPR, type,
+ iv0->base,
+ fold_build1 (NEGATE_EXPR,
+ type1, tmod)),
+ iv1->base);
else
noloop = fold_build2 (GT_EXPR, boolean_type_node,
- fold_build2 (MINUS_EXPR, type,
+ fold_build2 (MINUS_EXPR, type1,
iv0->base, tmod),
iv1->base);
}
struct tree_niter_desc *niter, bounds *bnds)
{
tree assumption = boolean_true_node, bound, diff;
- tree mbz, mbzl, mbzr;
+ tree mbz, mbzl, mbzr, type1;
bool rolls_p, no_overflow_p;
double_int dstep;
mpz_t mstep, max;
if (rolls_p && no_overflow_p)
return;
+
+ type1 = type;
+ if (POINTER_TYPE_P (type))
+ type1 = sizetype;
/* Now the hard part; we must formulate the assumption(s) as expressions, and
we must be careful not to introduce overflow. */
if (integer_nonzerop (iv0->step))
{
- diff = fold_build2 (MINUS_EXPR, type,
- iv0->step, build_int_cst (type, 1));
+ diff = fold_build2 (MINUS_EXPR, type1,
+ iv0->step, build_int_cst (type1, 1));
/* We need to know that iv0->base >= MIN + iv0->step - 1. Since
0 address never belongs to any object, we can assume this for
pointers. */
if (!POINTER_TYPE_P (type))
{
- bound = fold_build2 (PLUS_EXPR, type,
+ bound = fold_build2 (PLUS_EXPR, type1,
TYPE_MIN_VALUE (type), diff);
assumption = fold_build2 (GE_EXPR, boolean_type_node,
iv0->base, bound);
/* And then we can compute iv0->base - diff, and compare it with
iv1->base. */
- mbzl = fold_build2 (MINUS_EXPR, type, iv0->base, diff);
- mbzr = iv1->base;
+ mbzl = fold_build2 (MINUS_EXPR, type1,
+ fold_convert (type1, iv0->base), diff);
+ mbzr = fold_convert (type1, iv1->base);
}
else
{
- diff = fold_build2 (PLUS_EXPR, type,
- iv1->step, build_int_cst (type, 1));
+ diff = fold_build2 (PLUS_EXPR, type1,
+ iv1->step, build_int_cst (type1, 1));
if (!POINTER_TYPE_P (type))
{
- bound = fold_build2 (PLUS_EXPR, type,
+ bound = fold_build2 (PLUS_EXPR, type1,
TYPE_MAX_VALUE (type), diff);
assumption = fold_build2 (LE_EXPR, boolean_type_node,
iv1->base, bound);
}
- mbzl = iv0->base;
- mbzr = fold_build2 (MINUS_EXPR, type, iv1->base, diff);
+ mbzl = fold_convert (type1, iv0->base);
+ mbzr = fold_build2 (MINUS_EXPR, type1,
+ fold_convert (type1, iv1->base), diff);
}
if (!integer_nonzerop (assumption))
/* Determines number of iterations of loop whose ending condition
is IV0 < IV1. TYPE is the type of the iv. The number of
iterations is stored to NITER. BNDS bounds the difference
- IV1->base - IV0->base. */
+ IV1->base - IV0->base. EXIT_MUST_BE_TAKEN is true if we know
+ that the exit must be taken eventually. */
static bool
number_of_iterations_lt (tree type, affine_iv *iv0, affine_iv *iv1,
struct tree_niter_desc *niter,
- bool never_infinite ATTRIBUTE_UNUSED,
- bounds *bnds)
+ bool exit_must_be_taken, bounds *bnds)
{
tree niter_type = unsigned_type_for (type);
tree delta, step, s;
niter->may_be_zero = fold_build2 (LT_EXPR, boolean_type_node,
iv1->base, iv0->base);
niter->niter = delta;
- niter->max = mpz_to_double_int (niter_type, bnds->up);
+ niter->max = mpz_get_double_int (niter_type, bnds->up, false);
return true;
}
transform the condition to != comparison. In particular, this will be
the case if DELTA is constant. */
if (number_of_iterations_lt_to_ne (type, iv0, iv1, niter, &delta, step,
- bnds))
+ exit_must_be_taken, bnds))
{
affine_iv zps;
mpz_add (tmp, bnds->up, mstep);
mpz_sub_ui (tmp, tmp, 1);
mpz_fdiv_q (tmp, tmp, mstep);
- niter->max = mpz_to_double_int (niter_type, tmp);
+ niter->max = mpz_get_double_int (niter_type, tmp, false);
mpz_clear (mstep);
mpz_clear (tmp);
/* Determines number of iterations of loop whose ending condition
is IV0 <= IV1. TYPE is the type of the iv. The number of
- iterations is stored to NITER. NEVER_INFINITE is true if
+ iterations is stored to NITER. EXIT_MUST_BE_TAKEN is true if
we know that this condition must eventually become false (we derived this
earlier, and possibly set NITER->assumptions to make sure this
is the case). BNDS bounds the difference IV1->base - IV0->base. */
static bool
number_of_iterations_le (tree type, affine_iv *iv0, affine_iv *iv1,
- struct tree_niter_desc *niter, bool never_infinite,
+ struct tree_niter_desc *niter, bool exit_must_be_taken,
bounds *bnds)
{
tree assumption;
+ tree type1 = type;
+ if (POINTER_TYPE_P (type))
+ type1 = sizetype;
/* Say that IV0 is the control variable. Then IV0 <= IV1 iff
IV0 < IV1 + 1, assuming that IV1 is not equal to the greatest
value of the type. This we must know anyway, since if it is
- equal to this value, the loop rolls forever. */
+ equal to this value, the loop rolls forever. We do not check
+ this condition for pointer type ivs, as the code cannot rely on
+ the object to that the pointer points being placed at the end of
+ the address space (and more pragmatically, TYPE_{MIN,MAX}_VALUE is
+ not defined for pointers). */
- if (!never_infinite)
+ if (!exit_must_be_taken && !POINTER_TYPE_P (type))
{
if (integer_nonzerop (iv0->step))
assumption = fold_build2 (NE_EXPR, boolean_type_node,
}
if (integer_nonzerop (iv0->step))
- iv1->base = fold_build2 (PLUS_EXPR, type,
- iv1->base, build_int_cst (type, 1));
+ {
+ if (POINTER_TYPE_P (type))
+ iv1->base = fold_build2 (POINTER_PLUS_EXPR, type, iv1->base,
+ build_int_cst (type1, 1));
+ else
+ iv1->base = fold_build2 (PLUS_EXPR, type1, iv1->base,
+ build_int_cst (type1, 1));
+ }
+ else if (POINTER_TYPE_P (type))
+ iv0->base = fold_build2 (POINTER_PLUS_EXPR, type, iv0->base,
+ fold_build1 (NEGATE_EXPR, type1,
+ build_int_cst (type1, 1)));
else
- iv0->base = fold_build2 (MINUS_EXPR, type,
- iv0->base, build_int_cst (type, 1));
+ iv0->base = fold_build2 (MINUS_EXPR, type1,
+ iv0->base, build_int_cst (type1, 1));
- bounds_add (bnds, double_int_one, type);
+ bounds_add (bnds, double_int_one, type1);
- return number_of_iterations_lt (type, iv0, iv1, niter, never_infinite, bnds);
+ return number_of_iterations_lt (type, iv0, iv1, niter, exit_must_be_taken,
+ bnds);
}
/* Dumps description of affine induction variable IV to FILE. */
affine_iv *iv1, struct tree_niter_desc *niter,
bool only_exit)
{
- bool never_infinite, ret;
+ bool exit_must_be_taken = false, ret;
bounds bnds;
/* The meaning of these assumptions is this:
code = swap_tree_comparison (code);
}
- if (!only_exit)
- {
- /* If this is not the only possible exit from the loop, the information
- that the induction variables cannot overflow as derived from
- signedness analysis cannot be relied upon. We use them e.g. in the
- following way: given loop for (i = 0; i <= n; i++), if i is
- signed, it cannot overflow, thus this loop is equivalent to
- for (i = 0; i < n + 1; i++); however, if n == MAX, but the loop
- is exited in some other way before i overflows, this transformation
- is incorrect (the new loop exits immediately). */
- iv0->no_overflow = false;
- iv1->no_overflow = false;
- }
-
if (POINTER_TYPE_P (type))
{
/* Comparison of pointers is undefined unless both iv0 and iv1 point
to the same object. If they do, the control variable cannot wrap
(as wrap around the bounds of memory will never return a pointer
that would be guaranteed to point to the same object, even if we
- avoid undefined behavior by casting to size_t and back). The
- restrictions on pointer arithmetics and comparisons of pointers
- ensure that using the no-overflow assumptions is correct in this
- case even if ONLY_EXIT is false. */
+ avoid undefined behavior by casting to size_t and back). */
iv0->no_overflow = true;
iv1->no_overflow = true;
}
- /* If the control induction variable does not overflow, the loop obviously
- cannot be infinite. */
- if (!integer_zerop (iv0->step) && iv0->no_overflow)
- never_infinite = true;
- else if (!integer_zerop (iv1->step) && iv1->no_overflow)
- never_infinite = true;
- else
- never_infinite = false;
+ /* If the control induction variable does not overflow and the only exit
+ from the loop is the one that we analyze, we know it must be taken
+ eventually. */
+ if (only_exit)
+ {
+ if (!integer_zerop (iv0->step) && iv0->no_overflow)
+ exit_must_be_taken = true;
+ else if (!integer_zerop (iv1->step) && iv1->no_overflow)
+ exit_must_be_taken = true;
+ }
/* We can handle the case when neither of the sides of the comparison is
invariant, provided that the test is NE_EXPR. This rarely occurs in
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file,
- "Analysing # of iterations of loop %d\n", loop->num);
+ "Analyzing # of iterations of loop %d\n", loop->num);
fprintf (dump_file, " exit condition ");
dump_affine_iv (dump_file, iv0);
case NE_EXPR:
gcc_assert (integer_zerop (iv1->step));
ret = number_of_iterations_ne (type, iv0, iv1->base, niter,
- never_infinite, &bnds);
+ exit_must_be_taken, &bnds);
break;
case LT_EXPR:
- ret = number_of_iterations_lt (type, iv0, iv1, niter, never_infinite,
+ ret = number_of_iterations_lt (type, iv0, iv1, niter, exit_must_be_taken,
&bnds);
break;
case LE_EXPR:
- ret = number_of_iterations_le (type, iv0, iv1, niter, never_infinite,
+ ret = number_of_iterations_le (type, iv0, iv1, niter, exit_must_be_taken,
&bnds);
break;
/* Substitute NEW for OLD in EXPR and fold the result. */
static tree
-simplify_replace_tree (tree expr, tree old, tree new)
+simplify_replace_tree (tree expr, tree old, tree new_tree)
{
unsigned i, n;
tree ret = NULL_TREE, e, se;
if (expr == old
|| operand_equal_p (expr, old, 0))
- return unshare_expr (new);
+ return unshare_expr (new_tree);
- if (!EXPR_P (expr) && !GIMPLE_STMT_P (expr))
+ if (!EXPR_P (expr))
return expr;
n = TREE_OPERAND_LENGTH (expr);
for (i = 0; i < n; i++)
{
e = TREE_OPERAND (expr, i);
- se = simplify_replace_tree (e, old, new);
+ se = simplify_replace_tree (e, old, new_tree);
if (e == se)
continue;
expand_simple_operations (tree expr)
{
unsigned i, n;
- tree ret = NULL_TREE, e, ee, stmt;
+ tree ret = NULL_TREE, e, ee, e1;
enum tree_code code;
+ gimple stmt;
if (expr == NULL_TREE)
return expr;
return expr;
stmt = SSA_NAME_DEF_STMT (expr);
- if (TREE_CODE (stmt) == PHI_NODE)
+ if (gimple_code (stmt) == GIMPLE_PHI)
{
basic_block src, dest;
- if (PHI_NUM_ARGS (stmt) != 1)
+ if (gimple_phi_num_args (stmt) != 1)
return expr;
e = PHI_ARG_DEF (stmt, 0);
/* Avoid propagating through loop exit phi nodes, which
could break loop-closed SSA form restrictions. */
- dest = bb_for_stmt (stmt);
+ dest = gimple_bb (stmt);
src = single_pred (dest);
if (TREE_CODE (e) == SSA_NAME
&& src->loop_father != dest->loop_father)
return expand_simple_operations (e);
}
- if (TREE_CODE (stmt) != GIMPLE_MODIFY_STMT)
+ if (gimple_code (stmt) != GIMPLE_ASSIGN)
return expr;
- e = GIMPLE_STMT_OPERAND (stmt, 1);
- if (/* Casts are simple. */
- TREE_CODE (e) != NOP_EXPR
- && TREE_CODE (e) != CONVERT_EXPR
- /* Copies are simple. */
- && TREE_CODE (e) != SSA_NAME
- /* Assignments of invariants are simple. */
- && !is_gimple_min_invariant (e)
+ e = gimple_assign_rhs1 (stmt);
+ code = gimple_assign_rhs_code (stmt);
+ if (get_gimple_rhs_class (code) == GIMPLE_SINGLE_RHS)
+ {
+ if (is_gimple_min_invariant (e))
+ return e;
+
+ if (code == SSA_NAME)
+ return expand_simple_operations (e);
+
+ return expr;
+ }
+
+ switch (code)
+ {
+ CASE_CONVERT:
+ /* Casts are simple. */
+ ee = expand_simple_operations (e);
+ return fold_build1 (code, TREE_TYPE (expr), ee);
+
+ case PLUS_EXPR:
+ case MINUS_EXPR:
+ case POINTER_PLUS_EXPR:
/* And increments and decrements by a constant are simple. */
- && !((TREE_CODE (e) == PLUS_EXPR
- || TREE_CODE (e) == MINUS_EXPR)
- && is_gimple_min_invariant (TREE_OPERAND (e, 1))))
- return expr;
+ e1 = gimple_assign_rhs2 (stmt);
+ if (!is_gimple_min_invariant (e1))
+ return expr;
+
+ ee = expand_simple_operations (e);
+ return fold_build2 (code, TREE_TYPE (expr), ee, e1);
- return expand_simple_operations (e);
+ default:
+ return expr;
+ }
}
/* Tries to simplify EXPR using the condition COND. Returns the simplified
{
edge e;
basic_block bb;
+ gimple stmt;
tree cond;
int cnt = 0;
if (!(e->flags & (EDGE_TRUE_VALUE | EDGE_FALSE_VALUE)))
continue;
- cond = COND_EXPR_COND (last_stmt (e->src));
+ stmt = last_stmt (e->src);
+ cond = fold_build2 (gimple_cond_code (stmt),
+ boolean_type_node,
+ gimple_cond_lhs (stmt),
+ gimple_cond_rhs (stmt));
if (e->flags & EDGE_FALSE_VALUE)
cond = invert_truthvalue (cond);
expr = tree_simplify_using_condition (cond, expr);
/* Returns true if EXIT is the only possible exit from LOOP. */
-static bool
-loop_only_exit_p (struct loop *loop, edge exit)
+bool
+loop_only_exit_p (const struct loop *loop, const_edge exit)
{
basic_block *body;
- block_stmt_iterator bsi;
+ gimple_stmt_iterator bsi;
unsigned i;
- tree call;
+ gimple call;
if (exit != single_exit (loop))
return false;
body = get_loop_body (loop);
for (i = 0; i < loop->num_nodes; i++)
{
- for (bsi = bsi_start (body[0]); !bsi_end_p (bsi); bsi_next (&bsi))
+ for (bsi = gsi_start_bb (body[i]); !gsi_end_p (bsi); gsi_next (&bsi))
{
- call = get_call_expr_in (bsi_stmt (bsi));
- if (call && TREE_SIDE_EFFECTS (call))
+ call = gsi_stmt (bsi);
+ if (gimple_code (call) != GIMPLE_CALL)
+ continue;
+
+ if (gimple_has_side_effects (call))
{
free (body);
return false;
struct tree_niter_desc *niter,
bool warn)
{
- tree stmt, cond, type;
+ gimple stmt;
+ tree type;
tree op0, op1;
enum tree_code code;
affine_iv iv0, iv1;
niter->assumptions = boolean_false_node;
stmt = last_stmt (exit->src);
- if (!stmt || TREE_CODE (stmt) != COND_EXPR)
+ if (!stmt || gimple_code (stmt) != GIMPLE_COND)
return false;
/* We want the condition for staying inside loop. */
- cond = COND_EXPR_COND (stmt);
+ code = gimple_cond_code (stmt);
if (exit->flags & EDGE_TRUE_VALUE)
- cond = invert_truthvalue (cond);
+ code = invert_tree_comparison (code, false);
- code = TREE_CODE (cond);
switch (code)
{
case GT_EXPR:
return false;
}
- op0 = TREE_OPERAND (cond, 0);
- op1 = TREE_OPERAND (cond, 1);
+ op0 = gimple_cond_lhs (stmt);
+ op1 = gimple_cond_rhs (stmt);
type = TREE_TYPE (op0);
if (TREE_CODE (type) != INTEGER_TYPE
&& !POINTER_TYPE_P (type))
return false;
- if (!simple_iv (loop, stmt, op0, &iv0, false))
+ if (!simple_iv (loop, loop_containing_stmt (stmt), op0, &iv0, false))
return false;
- if (!simple_iv (loop, stmt, op1, &iv1, false))
+ if (!simple_iv (loop, loop_containing_stmt (stmt), op1, &iv1, false))
return false;
/* We don't want to see undefined signed overflow warnings while
if (warn)
{
const char *wording;
- location_t loc = EXPR_LOCATION (stmt);
+ location_t loc = gimple_location (stmt);
/* We can provide a more specific warning if one of the operator is
constant and the other advances by +1 or -1. */
? N_("assuming that the loop counter does not overflow")
: N_("cannot optimize loop, the loop counter may overflow");
- if (LOCATION_LINE (loc) > 0)
- warning (OPT_Wunsafe_loop_optimizations, "%H%s", &loc, gettext (wording));
- else
- warning (OPT_Wunsafe_loop_optimizations, "%s", gettext (wording));
+ warning_at ((LOCATION_LINE (loc) > 0) ? loc : input_location,
+ OPT_Wunsafe_loop_optimizations, "%s", gettext (wording));
}
return flag_unsafe_loop_optimizations;
return niter ? niter : chrec_dont_know;
}
+/* Return true if loop is known to have bounded number of iterations. */
+
+bool
+finite_loop_p (struct loop *loop)
+{
+ unsigned i;
+ VEC (edge, heap) *exits;
+ edge ex;
+ struct tree_niter_desc desc;
+ bool finite = false;
+
+ if (flag_unsafe_loop_optimizations)
+ return true;
+ if ((TREE_READONLY (current_function_decl)
+ || DECL_PURE_P (current_function_decl))
+ && !DECL_LOOPING_CONST_OR_PURE_P (current_function_decl))
+ {
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ fprintf (dump_file, "Found loop %i to be finite: it is within pure or const function.\n",
+ loop->num);
+ return true;
+ }
+
+ exits = get_loop_exit_edges (loop);
+ for (i = 0; VEC_iterate (edge, exits, i, ex); i++)
+ {
+ if (!just_once_each_iteration_p (loop, ex->src))
+ continue;
+
+ if (number_of_iterations_exit (loop, ex, &desc, false))
+ {
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, "Found loop %i to be finite: iterating ", loop->num);
+ print_generic_expr (dump_file, desc.niter, TDF_SLIM);
+ fprintf (dump_file, " times\n");
+ }
+ finite = true;
+ break;
+ }
+ }
+ VEC_free (edge, heap, exits);
+ return finite;
+}
+
/*
Analysis of a number of iterations of a loop by a brute-force evaluation.
result by a chain of operations such that all but exactly one of their
operands are constants. */
-static tree
+static gimple
chain_of_csts_start (struct loop *loop, tree x)
{
- tree stmt = SSA_NAME_DEF_STMT (x);
+ gimple stmt = SSA_NAME_DEF_STMT (x);
tree use;
- basic_block bb = bb_for_stmt (stmt);
+ basic_block bb = gimple_bb (stmt);
+ enum tree_code code;
if (!bb
|| !flow_bb_inside_loop_p (loop, bb))
- return NULL_TREE;
+ return NULL;
- if (TREE_CODE (stmt) == PHI_NODE)
+ if (gimple_code (stmt) == GIMPLE_PHI)
{
if (bb == loop->header)
return stmt;
- return NULL_TREE;
+ return NULL;
}
- if (TREE_CODE (stmt) != GIMPLE_MODIFY_STMT)
- return NULL_TREE;
+ if (gimple_code (stmt) != GIMPLE_ASSIGN)
+ return NULL;
- if (!ZERO_SSA_OPERANDS (stmt, SSA_OP_ALL_VIRTUALS))
- return NULL_TREE;
- if (SINGLE_SSA_DEF_OPERAND (stmt, SSA_OP_DEF) == NULL_DEF_OPERAND_P)
- return NULL_TREE;
+ code = gimple_assign_rhs_code (stmt);
+ if (gimple_references_memory_p (stmt)
+ || TREE_CODE_CLASS (code) == tcc_reference
+ || (code == ADDR_EXPR
+ && !is_gimple_min_invariant (gimple_assign_rhs1 (stmt))))
+ return NULL;
use = SINGLE_SSA_TREE_OPERAND (stmt, SSA_OP_USE);
- if (use == NULL_USE_OPERAND_P)
- return NULL_TREE;
+ if (use == NULL_TREE)
+ return NULL;
return chain_of_csts_start (loop, use);
}
* the value of the phi node in the next iteration can be derived from the
value in the current iteration by a chain of operations with constants.
- If such phi node exists, it is returned. If X is a constant, X is returned
- unchanged. Otherwise NULL_TREE is returned. */
+ If such phi node exists, it is returned, otherwise NULL is returned. */
-static tree
+static gimple
get_base_for (struct loop *loop, tree x)
{
- tree phi, init, next;
+ gimple phi;
+ tree init, next;
if (is_gimple_min_invariant (x))
- return x;
+ return NULL;
phi = chain_of_csts_start (loop, x);
if (!phi)
- return NULL_TREE;
+ return NULL;
init = PHI_ARG_DEF_FROM_EDGE (phi, loop_preheader_edge (loop));
next = PHI_ARG_DEF_FROM_EDGE (phi, loop_latch_edge (loop));
if (TREE_CODE (next) != SSA_NAME)
- return NULL_TREE;
+ return NULL;
if (!is_gimple_min_invariant (init))
- return NULL_TREE;
+ return NULL;
if (chain_of_csts_start (loop, next) != phi)
- return NULL_TREE;
+ return NULL;
return phi;
}
static tree
get_val_for (tree x, tree base)
{
- tree stmt, nx, val;
- use_operand_p op;
- ssa_op_iter iter;
+ gimple stmt;
gcc_assert (is_gimple_min_invariant (base));
return base;
stmt = SSA_NAME_DEF_STMT (x);
- if (TREE_CODE (stmt) == PHI_NODE)
+ if (gimple_code (stmt) == GIMPLE_PHI)
return base;
- FOR_EACH_SSA_USE_OPERAND (op, stmt, iter, SSA_OP_USE)
+ gcc_assert (is_gimple_assign (stmt));
+
+ /* STMT must be either an assignment of a single SSA name or an
+ expression involving an SSA name and a constant. Try to fold that
+ expression using the value for the SSA name. */
+ if (gimple_assign_ssa_name_copy_p (stmt))
+ return get_val_for (gimple_assign_rhs1 (stmt), base);
+ else if (gimple_assign_rhs_class (stmt) == GIMPLE_UNARY_RHS
+ && TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME)
{
- nx = USE_FROM_PTR (op);
- val = get_val_for (nx, base);
- SET_USE (op, val);
- val = fold (GIMPLE_STMT_OPERAND (stmt, 1));
- SET_USE (op, nx);
- /* only iterate loop once. */
- return val;
+ return fold_build1 (gimple_assign_rhs_code (stmt),
+ gimple_expr_type (stmt),
+ get_val_for (gimple_assign_rhs1 (stmt), base));
}
-
- /* Should never reach here. */
- gcc_unreachable ();
+ else if (gimple_assign_rhs_class (stmt) == GIMPLE_BINARY_RHS)
+ {
+ tree rhs1 = gimple_assign_rhs1 (stmt);
+ tree rhs2 = gimple_assign_rhs2 (stmt);
+ if (TREE_CODE (rhs1) == SSA_NAME)
+ rhs1 = get_val_for (rhs1, base);
+ else if (TREE_CODE (rhs2) == SSA_NAME)
+ rhs2 = get_val_for (rhs2, base);
+ else
+ gcc_unreachable ();
+ return fold_build2 (gimple_assign_rhs_code (stmt),
+ gimple_expr_type (stmt), rhs1, rhs2);
+ }
+ else
+ gcc_unreachable ();
}
+
/* Tries to count the number of iterations of LOOP till it exits by EXIT
by brute force -- i.e. by determining the value of the operands of the
condition at EXIT in first few iterations of the loop (assuming that
tree
loop_niter_by_eval (struct loop *loop, edge exit)
{
- tree cond, cnd, acnd;
- tree op[2], val[2], next[2], aval[2], phi[2];
+ tree acnd;
+ tree op[2], val[2], next[2], aval[2];
+ gimple phi, cond;
unsigned i, j;
enum tree_code cmp;
cond = last_stmt (exit->src);
- if (!cond || TREE_CODE (cond) != COND_EXPR)
+ if (!cond || gimple_code (cond) != GIMPLE_COND)
return chrec_dont_know;
- cnd = COND_EXPR_COND (cond);
+ cmp = gimple_cond_code (cond);
if (exit->flags & EDGE_TRUE_VALUE)
- cnd = invert_truthvalue (cnd);
+ cmp = invert_tree_comparison (cmp, false);
- cmp = TREE_CODE (cnd);
switch (cmp)
{
case EQ_EXPR:
case GE_EXPR:
case LT_EXPR:
case LE_EXPR:
- for (j = 0; j < 2; j++)
- op[j] = TREE_OPERAND (cnd, j);
+ op[0] = gimple_cond_lhs (cond);
+ op[1] = gimple_cond_rhs (cond);
break;
default:
for (j = 0; j < 2; j++)
{
- phi[j] = get_base_for (loop, op[j]);
- if (!phi[j])
- return chrec_dont_know;
- }
-
- for (j = 0; j < 2; j++)
- {
- if (TREE_CODE (phi[j]) == PHI_NODE)
+ if (is_gimple_min_invariant (op[j]))
{
- val[j] = PHI_ARG_DEF_FROM_EDGE (phi[j], loop_preheader_edge (loop));
- next[j] = PHI_ARG_DEF_FROM_EDGE (phi[j], loop_latch_edge (loop));
+ val[j] = op[j];
+ next[j] = NULL_TREE;
+ op[j] = NULL_TREE;
}
else
{
- val[j] = phi[j];
- next[j] = NULL_TREE;
- op[j] = NULL_TREE;
+ phi = get_base_for (loop, op[j]);
+ if (!phi)
+ return chrec_dont_know;
+ val[j] = PHI_ARG_DEF_FROM_EDGE (phi, loop_preheader_edge (loop));
+ next[j] = PHI_ARG_DEF_FROM_EDGE (phi, loop_latch_edge (loop));
}
}
tree niter = NULL_TREE, aniter;
*exit = NULL;
+
+ /* Loops with multiple exits are expensive to handle and less important. */
+ if (!flag_expensive_optimizations
+ && VEC_length (edge, exits) > 1)
+ return chrec_dont_know;
+
for (i = 0; VEC_iterate (edge, exits, i, ex); i++)
{
if (!just_once_each_iteration_p (loop, ex->src))
*/
+static double_int derive_constant_upper_bound_ops (tree, tree,
+ enum tree_code, tree);
+
+/* Returns a constant upper bound on the value of the right-hand side of
+ an assignment statement STMT. */
+
+static double_int
+derive_constant_upper_bound_assign (gimple stmt)
+{
+ enum tree_code code = gimple_assign_rhs_code (stmt);
+ tree op0 = gimple_assign_rhs1 (stmt);
+ tree op1 = gimple_assign_rhs2 (stmt);
+
+ return derive_constant_upper_bound_ops (TREE_TYPE (gimple_assign_lhs (stmt)),
+ op0, code, op1);
+}
+
/* Returns a constant upper bound on the value of expression VAL. VAL
is considered to be unsigned. If its type is signed, its value must
be nonnegative. */
static double_int
derive_constant_upper_bound (tree val)
{
- tree type = TREE_TYPE (val);
- tree op0, op1, subtype, maxt;
+ enum tree_code code;
+ tree op0, op1;
+
+ extract_ops_from_tree (val, &code, &op0, &op1);
+ return derive_constant_upper_bound_ops (TREE_TYPE (val), op0, code, op1);
+}
+
+/* Returns a constant upper bound on the value of expression OP0 CODE OP1,
+ whose type is TYPE. The expression is considered to be unsigned. If
+ its type is signed, its value must be nonnegative. */
+
+static double_int
+derive_constant_upper_bound_ops (tree type, tree op0,
+ enum tree_code code, tree op1)
+{
+ tree subtype, maxt;
double_int bnd, max, mmax, cst;
- tree stmt;
+ gimple stmt;
if (INTEGRAL_TYPE_P (type))
maxt = TYPE_MAX_VALUE (type);
max = tree_to_double_int (maxt);
- switch (TREE_CODE (val))
+ switch (code)
{
case INTEGER_CST:
- return tree_to_double_int (val);
+ return tree_to_double_int (op0);
- case NOP_EXPR:
- case CONVERT_EXPR:
- op0 = TREE_OPERAND (val, 0);
+ CASE_CONVERT:
subtype = TREE_TYPE (op0);
if (!TYPE_UNSIGNED (subtype)
/* If TYPE is also signed, the fact that VAL is nonnegative implies
return bnd;
case PLUS_EXPR:
+ case POINTER_PLUS_EXPR:
case MINUS_EXPR:
- op0 = TREE_OPERAND (val, 0);
- op1 = TREE_OPERAND (val, 1);
-
if (TREE_CODE (op1) != INTEGER_CST
|| !tree_expr_nonnegative_p (op0))
return max;
of the signedness of the type. */
cst = tree_to_double_int (op1);
cst = double_int_sext (cst, TYPE_PRECISION (type));
- if (TREE_CODE (val) == PLUS_EXPR)
+ if (code != MINUS_EXPR)
cst = double_int_neg (cst);
bnd = derive_constant_upper_bound (op0);
case FLOOR_DIV_EXPR:
case EXACT_DIV_EXPR:
- op0 = TREE_OPERAND (val, 0);
- op1 = TREE_OPERAND (val, 1);
if (TREE_CODE (op1) != INTEGER_CST
|| tree_int_cst_sign_bit (op1))
return max;
return double_int_udiv (bnd, tree_to_double_int (op1), FLOOR_DIV_EXPR);
case BIT_AND_EXPR:
- op1 = TREE_OPERAND (val, 1);
if (TREE_CODE (op1) != INTEGER_CST
|| tree_int_cst_sign_bit (op1))
return max;
return tree_to_double_int (op1);
case SSA_NAME:
- stmt = SSA_NAME_DEF_STMT (val);
- if (TREE_CODE (stmt) != GIMPLE_MODIFY_STMT
- || GIMPLE_STMT_OPERAND (stmt, 0) != val)
+ stmt = SSA_NAME_DEF_STMT (op0);
+ if (gimple_code (stmt) != GIMPLE_ASSIGN
+ || gimple_assign_lhs (stmt) != op0)
return max;
- return derive_constant_upper_bound (GIMPLE_STMT_OPERAND (stmt, 1));
+ return derive_constant_upper_bound_assign (stmt);
default:
return max;
}
}
+/* Records that every statement in LOOP is executed I_BOUND times.
+ REALISTIC is true if I_BOUND is expected to be close to the real number
+ of iterations. UPPER is true if we are sure the loop iterates at most
+ I_BOUND times. */
+
+static void
+record_niter_bound (struct loop *loop, double_int i_bound, bool realistic,
+ bool upper)
+{
+ /* Update the bounds only when there is no previous estimation, or when the current
+ estimation is smaller. */
+ if (upper
+ && (!loop->any_upper_bound
+ || double_int_ucmp (i_bound, loop->nb_iterations_upper_bound) < 0))
+ {
+ loop->any_upper_bound = true;
+ loop->nb_iterations_upper_bound = i_bound;
+ }
+ if (realistic
+ && (!loop->any_estimate
+ || double_int_ucmp (i_bound, loop->nb_iterations_estimate) < 0))
+ {
+ loop->any_estimate = true;
+ loop->nb_iterations_estimate = i_bound;
+ }
+}
+
/* Records that AT_STMT is executed at most BOUND + 1 times in LOOP. IS_EXIT
is true if the loop is exited immediately after STMT, and this exit
is taken at last when the STMT is executed BOUND + 1 times.
- REALISTIC is true if the estimate comes from a reliable source
- (number of iterations analysis, or size of data accessed in the loop).
- I_BOUND is an unsigned double_int upper estimate on BOUND. */
+ REALISTIC is true if BOUND is expected to be close to the real number
+ of iterations. UPPER is true if we are sure the loop iterates at most
+ BOUND times. I_BOUND is an unsigned double_int upper estimate on BOUND. */
static void
record_estimate (struct loop *loop, tree bound, double_int i_bound,
- tree at_stmt, bool is_exit, bool realistic)
+ gimple at_stmt, bool is_exit, bool realistic, bool upper)
{
- struct nb_iter_bound *elt = xmalloc (sizeof (struct nb_iter_bound));
+ double_int delta;
+ edge exit;
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "Statement %s", is_exit ? "(exit)" : "");
- print_generic_expr (dump_file, at_stmt, TDF_SLIM);
- fprintf (dump_file, " is executed at most ");
+ print_gimple_stmt (dump_file, at_stmt, 0, TDF_SLIM);
+ fprintf (dump_file, " is %sexecuted at most ",
+ upper ? "" : "probably ");
print_generic_expr (dump_file, bound, TDF_SLIM);
fprintf (dump_file, " (bounded by ");
dump_double_int (dump_file, i_bound, true);
fprintf (dump_file, ") + 1 times in loop %d.\n", loop->num);
}
- elt->bound = i_bound;
- elt->stmt = at_stmt;
- elt->is_exit = is_exit;
- elt->realistic = realistic && TREE_CODE (bound) == INTEGER_CST;
- elt->next = loop->bounds;
- loop->bounds = elt;
+ /* If the I_BOUND is just an estimate of BOUND, it rarely is close to the
+ real number of iterations. */
+ if (TREE_CODE (bound) != INTEGER_CST)
+ realistic = false;
+ if (!upper && !realistic)
+ return;
+
+ /* If we have a guaranteed upper bound, record it in the appropriate
+ list. */
+ if (upper)
+ {
+ struct nb_iter_bound *elt = GGC_NEW (struct nb_iter_bound);
+
+ elt->bound = i_bound;
+ elt->stmt = at_stmt;
+ elt->is_exit = is_exit;
+ elt->next = loop->bounds;
+ loop->bounds = elt;
+ }
+
+ /* Update the number of iteration estimates according to the bound.
+ If at_stmt is an exit, then every statement in the loop is
+ executed at most BOUND + 1 times. If it is not an exit, then
+ some of the statements before it could be executed BOUND + 2
+ times, if an exit of LOOP is before stmt. */
+ exit = single_exit (loop);
+ if (is_exit
+ || (exit != NULL
+ && dominated_by_p (CDI_DOMINATORS,
+ exit->src, gimple_bb (at_stmt))))
+ delta = double_int_one;
+ else
+ delta = double_int_two;
+ i_bound = double_int_add (i_bound, delta);
+
+ /* If an overflow occurred, ignore the result. */
+ if (double_int_ucmp (i_bound, delta) < 0)
+ return;
+
+ record_niter_bound (loop, i_bound, realistic, upper);
}
/* Record the estimate on number of iterations of LOOP based on the fact that
the induction variable BASE + STEP * i evaluated in STMT does not wrap and
- its values belong to the range <LOW, HIGH>. DATA_SIZE_BOUNDS_P is true if
- LOW and HIGH are derived from the size of data. */
+ its values belong to the range <LOW, HIGH>. REALISTIC is true if the
+ estimated number of iterations is expected to be close to the real one.
+ UPPER is true if we are sure the induction variable does not wrap. */
static void
-record_nonwrapping_iv (struct loop *loop, tree base, tree step, tree stmt,
- tree low, tree high, bool data_size_bounds_p)
+record_nonwrapping_iv (struct loop *loop, tree base, tree step, gimple stmt,
+ tree low, tree high, bool realistic, bool upper)
{
tree niter_bound, extreme, delta;
tree type = TREE_TYPE (base), unsigned_type;
fprintf (dump_file, " + ");
print_generic_expr (dump_file, step, TDF_SLIM);
fprintf (dump_file, " * iteration does not wrap in statement ");
- print_generic_expr (dump_file, stmt, TDF_SLIM);
+ print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM);
fprintf (dump_file, " in loop %d.\n", loop->num);
}
would get out of the range. */
niter_bound = fold_build2 (FLOOR_DIV_EXPR, unsigned_type, delta, step);
max = derive_constant_upper_bound (niter_bound);
- record_estimate (loop, niter_bound, max, stmt, false, data_size_bounds_p);
-}
-
-/* Initialize LOOP->ESTIMATED_NB_ITERATIONS with the lowest safe
- approximation of the number of iterations for LOOP. */
-
-static void
-compute_estimated_nb_iterations (struct loop *loop)
-{
- struct nb_iter_bound *bound;
- double_int bnd_val, delta;
- edge exit;
-
- gcc_assert (loop->estimate_state == EST_NOT_AVAILABLE);
-
- for (bound = loop->bounds; bound; bound = bound->next)
- {
- if (!bound->realistic)
- continue;
-
- bnd_val = bound->bound;
- /* If bound->stmt is an exit, then every statement in the loop is
- executed at most BND_VAL + 1 times. If it is not an exit, then
- some of the statements before it could be executed BND_VAL + 2
- times, if an exit of LOOP is before stmt. */
- exit = single_exit (loop);
-
- if (bound->is_exit
- || (exit != NULL
- && dominated_by_p (CDI_DOMINATORS,
- exit->src, bb_for_stmt (bound->stmt))))
- delta = double_int_one;
- else
- delta = double_int_two;
- bnd_val = double_int_add (bnd_val, delta);
-
- /* If an overflow occured, ignore the result. */
- if (double_int_ucmp (bnd_val, delta) < 0)
- continue;
-
- /* Update only when there is no previous estimation, or when the current
- estimation is smaller. */
- if (loop->estimate_state == EST_NOT_AVAILABLE
- || double_int_ucmp (bnd_val, loop->estimated_nb_iterations) < 0)
- {
- loop->estimate_state = EST_AVAILABLE;
- loop->estimated_nb_iterations = bnd_val;
- }
- }
+ record_estimate (loop, niter_bound, max, stmt, false, realistic, upper);
}
/* Returns true if REF is a reference to an array at the end of a dynamically
allocated structure. If this is the case, the array may be allocated larger
than its upper bound implies. */
-static bool
+bool
array_at_struct_end_p (tree ref)
{
tree base = get_base_address (ref);
}
/* Determine information about number of iterations a LOOP from the index
- IDX of a data reference accessed in STMT. Callback for for_each_index. */
+ IDX of a data reference accessed in STMT. RELIABLE is true if STMT is
+ guaranteed to be executed in every iteration of LOOP. Callback for
+ for_each_index. */
struct ilb_data
{
struct loop *loop;
- tree stmt;
+ gimple stmt;
+ bool reliable;
};
static bool
idx_infer_loop_bounds (tree base, tree *idx, void *dta)
{
- struct ilb_data *data = dta;
+ struct ilb_data *data = (struct ilb_data *) dta;
tree ev, init, step;
tree low, high, type, next;
- bool sign;
+ bool sign, upper = data->reliable, at_end = false;
struct loop *loop = data->loop;
- if (TREE_CODE (base) != ARRAY_REF
- || array_at_struct_end_p (base))
+ if (TREE_CODE (base) != ARRAY_REF)
return true;
+ /* For arrays at the end of the structure, we are not guaranteed that they
+ do not really extend over their declared size. However, for arrays of
+ size greater than one, this is unlikely to be intended. */
+ if (array_at_struct_end_p (base))
+ {
+ at_end = true;
+ upper = false;
+ }
+
ev = instantiate_parameters (loop, analyze_scalar_evolution (loop, *idx));
init = initial_condition (ev);
step = evolution_part_in_loop_num (ev, loop->num);
return true;
sign = tree_int_cst_sign_bit (step);
type = TREE_TYPE (step);
-
+
+ /* The array of length 1 at the end of a structure most likely extends
+ beyond its bounds. */
+ if (at_end
+ && operand_equal_p (low, high, 0))
+ return true;
+
/* In case the relevant bound of the array does not fit in type, or
it does, but bound + step (in type) still belongs into the range of the
array, the index may wrap and still stay within the range of the array
&& tree_int_cst_compare (next, high) <= 0)
return true;
- record_nonwrapping_iv (loop, init, step, data->stmt, low, high, true);
+ record_nonwrapping_iv (loop, init, step, data->stmt, low, high, true, upper);
return true;
}
/* Determine information about number of iterations a LOOP from the bounds
- of arrays in the data reference REF accessed in STMT. */
+ of arrays in the data reference REF accessed in STMT. RELIABLE is true if
+ STMT is guaranteed to be executed in every iteration of LOOP.*/
static void
-infer_loop_bounds_from_ref (struct loop *loop, tree stmt, tree ref)
+infer_loop_bounds_from_ref (struct loop *loop, gimple stmt, tree ref,
+ bool reliable)
{
struct ilb_data data;
data.loop = loop;
data.stmt = stmt;
+ data.reliable = reliable;
for_each_index (&ref, idx_infer_loop_bounds, &data);
}
/* Determine information about number of iterations of a LOOP from the way
- arrays are used in STMT. */
+ arrays are used in STMT. RELIABLE is true if STMT is guaranteed to be
+ executed in every iteration of LOOP. */
static void
-infer_loop_bounds_from_array (struct loop *loop, tree stmt)
+infer_loop_bounds_from_array (struct loop *loop, gimple stmt, bool reliable)
{
- tree call;
-
- if (TREE_CODE (stmt) == GIMPLE_MODIFY_STMT)
+ if (is_gimple_assign (stmt))
{
- tree op0 = GIMPLE_STMT_OPERAND (stmt, 0);
- tree op1 = GIMPLE_STMT_OPERAND (stmt, 1);
+ tree op0 = gimple_assign_lhs (stmt);
+ tree op1 = gimple_assign_rhs1 (stmt);
/* For each memory access, analyze its access function
and record a bound on the loop iteration domain. */
if (REFERENCE_CLASS_P (op0))
- infer_loop_bounds_from_ref (loop, stmt, op0);
+ infer_loop_bounds_from_ref (loop, stmt, op0, reliable);
if (REFERENCE_CLASS_P (op1))
- infer_loop_bounds_from_ref (loop, stmt, op1);
+ infer_loop_bounds_from_ref (loop, stmt, op1, reliable);
}
-
-
- call = get_call_expr_in (stmt);
- if (call)
+ else if (is_gimple_call (stmt))
{
- tree arg;
- call_expr_arg_iterator iter;
+ tree arg, lhs;
+ unsigned i, n = gimple_call_num_args (stmt);
+
+ lhs = gimple_call_lhs (stmt);
+ if (lhs && REFERENCE_CLASS_P (lhs))
+ infer_loop_bounds_from_ref (loop, stmt, lhs, reliable);
- FOR_EACH_CALL_EXPR_ARG (arg, iter, call)
- if (REFERENCE_CLASS_P (arg))
- infer_loop_bounds_from_ref (loop, stmt, arg);
+ for (i = 0; i < n; i++)
+ {
+ arg = gimple_call_arg (stmt, i);
+ if (REFERENCE_CLASS_P (arg))
+ infer_loop_bounds_from_ref (loop, stmt, arg, reliable);
+ }
}
}
that signed arithmetics in STMT does not overflow. */
static void
-infer_loop_bounds_from_signedness (struct loop *loop, tree stmt)
+infer_loop_bounds_from_signedness (struct loop *loop, gimple stmt)
{
tree def, base, step, scev, type, low, high;
- if (TREE_CODE (stmt) != GIMPLE_MODIFY_STMT)
+ if (gimple_code (stmt) != GIMPLE_ASSIGN)
return;
- def = GIMPLE_STMT_OPERAND (stmt, 0);
+ def = gimple_assign_lhs (stmt);
if (TREE_CODE (def) != SSA_NAME)
return;
low = lower_bound_in_type (type, type);
high = upper_bound_in_type (type, type);
- record_nonwrapping_iv (loop, base, step, stmt, low, high, false);
+ record_nonwrapping_iv (loop, base, step, stmt, low, high, false, true);
}
/* The following analyzers are extracting informations on the bounds
{
unsigned i;
basic_block *bbs;
- block_stmt_iterator bsi;
+ gimple_stmt_iterator bsi;
basic_block bb;
+ bool reliable;
bbs = get_loop_body (loop);
bb = bbs[i];
/* If BB is not executed in each iteration of the loop, we cannot
- use it to infer any information about # of iterations of the loop. */
- if (!dominated_by_p (CDI_DOMINATORS, loop->latch, bb))
- continue;
+ use the operations in it to infer reliable upper bound on the
+ # of iterations of the loop. However, we can use it as a guess. */
+ reliable = dominated_by_p (CDI_DOMINATORS, loop->latch, bb);
- for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
+ for (bsi = gsi_start_bb (bb); !gsi_end_p (bsi); gsi_next (&bsi))
{
- tree stmt = bsi_stmt (bsi);
+ gimple stmt = gsi_stmt (bsi);
- infer_loop_bounds_from_array (loop, stmt);
- infer_loop_bounds_from_signedness (loop, stmt);
+ infer_loop_bounds_from_array (loop, stmt, reliable);
+
+ if (reliable)
+ infer_loop_bounds_from_signedness (loop, stmt);
}
}
free (bbs);
}
+/* Converts VAL to double_int. */
+
+static double_int
+gcov_type_to_double_int (gcov_type val)
+{
+ double_int ret;
+
+ ret.low = (unsigned HOST_WIDE_INT) val;
+ /* If HOST_BITS_PER_WIDE_INT == HOST_BITS_PER_WIDEST_INT, avoid shifting by
+ the size of type. */
+ val >>= HOST_BITS_PER_WIDE_INT - 1;
+ val >>= 1;
+ ret.high = (unsigned HOST_WIDE_INT) val;
+
+ return ret;
+}
+
/* Records estimates on numbers of iterations of LOOP. */
void
unsigned i;
struct tree_niter_desc niter_desc;
edge ex;
+ double_int bound;
/* Give up if we already have tried to compute an estimation. */
if (loop->estimate_state != EST_NOT_COMPUTED)
return;
- loop->estimate_state = EST_NOT_AVAILABLE;
+ loop->estimate_state = EST_AVAILABLE;
+ loop->any_upper_bound = false;
+ loop->any_estimate = false;
exits = get_loop_exit_edges (loop);
for (i = 0; VEC_iterate (edge, exits, i, ex); i++)
niter);
record_estimate (loop, niter, niter_desc.max,
last_stmt (ex->src),
- true, true);
+ true, true, true);
}
VEC_free (edge, heap, exits);
infer_loop_bounds_from_undefined (loop);
- compute_estimated_nb_iterations (loop);
+
+ /* If we have a measured profile, use it to estimate the number of
+ iterations. */
+ if (loop->header->count != 0)
+ {
+ gcov_type nit = expected_loop_iterations_unbounded (loop) + 1;
+ bound = gcov_type_to_double_int (nit);
+ record_niter_bound (loop, bound, true, false);
+ }
+
+ /* If an upper bound is smaller than the realistic estimate of the
+ number of iterations, use the upper bound instead. */
+ if (loop->any_upper_bound
+ && loop->any_estimate
+ && double_int_ucmp (loop->nb_iterations_upper_bound,
+ loop->nb_iterations_estimate) < 0)
+ loop->nb_iterations_estimate = loop->nb_iterations_upper_bound;
}
/* Records estimates on numbers of iterations of loops. */
/* Returns true if statement S1 dominates statement S2. */
-static bool
-stmt_dominates_stmt_p (tree s1, tree s2)
+bool
+stmt_dominates_stmt_p (gimple s1, gimple s2)
{
- basic_block bb1 = bb_for_stmt (s1), bb2 = bb_for_stmt (s2);
+ basic_block bb1 = gimple_bb (s1), bb2 = gimple_bb (s2);
if (!bb1
|| s1 == s2)
if (bb1 == bb2)
{
- block_stmt_iterator bsi;
+ gimple_stmt_iterator bsi;
+
+ if (gimple_code (s2) == GIMPLE_PHI)
+ return false;
- for (bsi = bsi_start (bb1); bsi_stmt (bsi) != s2; bsi_next (&bsi))
- if (bsi_stmt (bsi) == s1)
+ if (gimple_code (s1) == GIMPLE_PHI)
+ return true;
+
+ for (bsi = gsi_start_bb (bb1); gsi_stmt (bsi) != s2; gsi_next (&bsi))
+ if (gsi_stmt (bsi) == s1)
return true;
return false;
statements in the loop. */
static bool
-n_of_executions_at_most (tree stmt,
+n_of_executions_at_most (gimple stmt,
struct nb_iter_bound *niter_bound,
tree niter)
{
else
{
if (!stmt
- || (bb_for_stmt (stmt) != bb_for_stmt (niter_bound->stmt)
+ || (gimple_bb (stmt) != gimple_bb (niter_bound->stmt)
&& !stmt_dominates_stmt_p (niter_bound->stmt, stmt)))
{
bound = double_int_add (bound, double_int_one);
bool
scev_probably_wraps_p (tree base, tree step,
- tree at_stmt, struct loop *loop,
+ gimple at_stmt, struct loop *loop,
bool use_overflow_semantics)
{
struct nb_iter_bound *bound;
2032, 2040, 0, 8, ..., but the code is still legal. */
if (chrec_contains_undetermined (base)
- || chrec_contains_undetermined (step)
- || TREE_CODE (step) != INTEGER_CST)
+ || chrec_contains_undetermined (step))
return true;
if (integer_zerop (step))
/* If we can use the fact that signed and pointer arithmetics does not
wrap, we are done. */
- if (use_overflow_semantics && nowrap_type_p (type))
+ if (use_overflow_semantics && nowrap_type_p (TREE_TYPE (base)))
return false;
+ /* To be able to use estimates on number of iterations of the loop,
+ we must have an upper bound on the absolute value of the step. */
+ if (TREE_CODE (step) != INTEGER_CST)
+ return true;
+
/* Don't issue signed overflow warnings. */
fold_defer_overflow_warnings ();
for (bound = loop->bounds; bound; bound = next)
{
next = bound->next;
- free (bound);
+ ggc_free (bound);
}
loop->bounds = NULL;
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