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/* Reassociation for trees.
Copyright (C) 2005-2013 Free Software Foundation, Inc.
Contributed by Daniel Berlin <dan@dberlin.org>
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/>. */
#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include "tree.h"
#include "basic-block.h"
#include "gimple-pretty-print.h"
#include "tree-inline.h"
#include "tree-flow.h"
#include "gimple.h"
#include "tree-iterator.h"
#include "tree-pass.h"
#include "alloc-pool.h"
#include "vec.h"
#include "langhooks.h"
#include "pointer-set.h"
#include "cfgloop.h"
#include "flags.h"
#include "target.h"
#include "params.h"
#include "diagnostic-core.h"
/* This is a simple global reassociation pass. It is, in part, based
on the LLVM pass of the same name (They do some things more/less
than we do, in different orders, etc).
It consists of five steps:
1. Breaking up subtract operations into addition + negate, where
it would promote the reassociation of adds.
2. Left linearization of the expression trees, so that (A+B)+(C+D)
becomes (((A+B)+C)+D), which is easier for us to rewrite later.
During linearization, we place the operands of the binary
expressions into a vector of operand_entry_t
3. Optimization of the operand lists, eliminating things like a +
-a, a & a, etc.
3a. Combine repeated factors with the same occurrence counts
into a __builtin_powi call that will later be optimized into
an optimal number of multiplies.
4. Rewrite the expression trees we linearized and optimized so
they are in proper rank order.
5. Repropagate negates, as nothing else will clean it up ATM.
A bit of theory on #4, since nobody seems to write anything down
about why it makes sense to do it the way they do it:
We could do this much nicer theoretically, but don't (for reasons
explained after how to do it theoretically nice :P).
In order to promote the most redundancy elimination, you want
binary expressions whose operands are the same rank (or
preferably, the same value) exposed to the redundancy eliminator,
for possible elimination.
So the way to do this if we really cared, is to build the new op
tree from the leaves to the roots, merging as you go, and putting the
new op on the end of the worklist, until you are left with one
thing on the worklist.
IE if you have to rewrite the following set of operands (listed with
rank in parentheses), with opcode PLUS_EXPR:
a (1), b (1), c (1), d (2), e (2)
We start with our merge worklist empty, and the ops list with all of
those on it.
You want to first merge all leaves of the same rank, as much as
possible.
So first build a binary op of
mergetmp = a + b, and put "mergetmp" on the merge worklist.
Because there is no three operand form of PLUS_EXPR, c is not going to
be exposed to redundancy elimination as a rank 1 operand.
So you might as well throw it on the merge worklist (you could also
consider it to now be a rank two operand, and merge it with d and e,
but in this case, you then have evicted e from a binary op. So at
least in this situation, you can't win.)
Then build a binary op of d + e
mergetmp2 = d + e
and put mergetmp2 on the merge worklist.
so merge worklist = {mergetmp, c, mergetmp2}
Continue building binary ops of these operations until you have only
one operation left on the worklist.
So we have
build binary op
mergetmp3 = mergetmp + c
worklist = {mergetmp2, mergetmp3}
mergetmp4 = mergetmp2 + mergetmp3
worklist = {mergetmp4}
because we have one operation left, we can now just set the original
statement equal to the result of that operation.
This will at least expose a + b and d + e to redundancy elimination
as binary operations.
For extra points, you can reuse the old statements to build the
mergetmps, since you shouldn't run out.
So why don't we do this?
Because it's expensive, and rarely will help. Most trees we are
reassociating have 3 or less ops. If they have 2 ops, they already
will be written into a nice single binary op. If you have 3 ops, a
single simple check suffices to tell you whether the first two are of the
same rank. If so, you know to order it
mergetmp = op1 + op2
newstmt = mergetmp + op3
instead of
mergetmp = op2 + op3
newstmt = mergetmp + op1
If all three are of the same rank, you can't expose them all in a
single binary operator anyway, so the above is *still* the best you
can do.
Thus, this is what we do. When we have three ops left, we check to see
what order to put them in, and call it a day. As a nod to vector sum
reduction, we check if any of the ops are really a phi node that is a
destructive update for the associating op, and keep the destructive
update together for vector sum reduction recognition. */
/* Statistics */
static struct
{
int linearized;
int constants_eliminated;
int ops_eliminated;
int rewritten;
int pows_encountered;
int pows_created;
} reassociate_stats;
/* Operator, rank pair. */
typedef struct operand_entry
{
unsigned int rank;
int id;
tree op;
unsigned int count;
} *operand_entry_t;
static alloc_pool operand_entry_pool;
/* This is used to assign a unique ID to each struct operand_entry
so that qsort results are identical on different hosts. */
static int next_operand_entry_id;
/* Starting rank number for a given basic block, so that we can rank
operations using unmovable instructions in that BB based on the bb
depth. */
static long *bb_rank;
/* Operand->rank hashtable. */
static struct pointer_map_t *operand_rank;
/* Forward decls. */
static long get_rank (tree);
/* Bias amount for loop-carried phis. We want this to be larger than
the depth of any reassociation tree we can see, but not larger than
the rank difference between two blocks. */
#define PHI_LOOP_BIAS (1 << 15)
/* Rank assigned to a phi statement. If STMT is a loop-carried phi of
an innermost loop, and the phi has only a single use which is inside
the loop, then the rank is the block rank of the loop latch plus an
extra bias for the loop-carried dependence. This causes expressions
calculated into an accumulator variable to be independent for each
iteration of the loop. If STMT is some other phi, the rank is the
block rank of its containing block. */
static long
phi_rank (gimple stmt)
{
basic_block bb = gimple_bb (stmt);
struct loop *father = bb->loop_father;
tree res;
unsigned i;
use_operand_p use;
gimple use_stmt;
/* We only care about real loops (those with a latch). */
if (!father->latch)
return bb_rank[bb->index];
/* Interesting phis must be in headers of innermost loops. */
if (bb != father->header
|| father->inner)
return bb_rank[bb->index];
/* Ignore virtual SSA_NAMEs. */
res = gimple_phi_result (stmt);
if (virtual_operand_p (res))
return bb_rank[bb->index];
/* The phi definition must have a single use, and that use must be
within the loop. Otherwise this isn't an accumulator pattern. */
if (!single_imm_use (res, &use, &use_stmt)
|| gimple_bb (use_stmt)->loop_father != father)
return bb_rank[bb->index];
/* Look for phi arguments from within the loop. If found, bias this phi. */
for (i = 0; i < gimple_phi_num_args (stmt); i++)
{
tree arg = gimple_phi_arg_def (stmt, i);
if (TREE_CODE (arg) == SSA_NAME
&& !SSA_NAME_IS_DEFAULT_DEF (arg))
{
gimple def_stmt = SSA_NAME_DEF_STMT (arg);
if (gimple_bb (def_stmt)->loop_father == father)
return bb_rank[father->latch->index] + PHI_LOOP_BIAS;
}
}
/* Must be an uninteresting phi. */
return bb_rank[bb->index];
}
/* If EXP is an SSA_NAME defined by a PHI statement that represents a
loop-carried dependence of an innermost loop, return TRUE; else
return FALSE. */
static bool
loop_carried_phi (tree exp)
{
gimple phi_stmt;
long block_rank;
if (TREE_CODE (exp) != SSA_NAME
|| SSA_NAME_IS_DEFAULT_DEF (exp))
return false;
phi_stmt = SSA_NAME_DEF_STMT (exp);
if (gimple_code (SSA_NAME_DEF_STMT (exp)) != GIMPLE_PHI)
return false;
/* Non-loop-carried phis have block rank. Loop-carried phis have
an additional bias added in. If this phi doesn't have block rank,
it's biased and should not be propagated. */
block_rank = bb_rank[gimple_bb (phi_stmt)->index];
if (phi_rank (phi_stmt) != block_rank)
return true;
return false;
}
/* Return the maximum of RANK and the rank that should be propagated
from expression OP. For most operands, this is just the rank of OP.
For loop-carried phis, the value is zero to avoid undoing the bias
in favor of the phi. */
static long
propagate_rank (long rank, tree op)
{
long op_rank;
if (loop_carried_phi (op))
return rank;
op_rank = get_rank (op);
return MAX (rank, op_rank);
}
/* Look up the operand rank structure for expression E. */
static inline long
find_operand_rank (tree e)
{
void **slot = pointer_map_contains (operand_rank, e);
return slot ? (long) (intptr_t) *slot : -1;
}
/* Insert {E,RANK} into the operand rank hashtable. */
static inline void
insert_operand_rank (tree e, long rank)
{
void **slot;
gcc_assert (rank > 0);
slot = pointer_map_insert (operand_rank, e);
gcc_assert (!*slot);
*slot = (void *) (intptr_t) rank;
}
/* Given an expression E, return the rank of the expression. */
static long
get_rank (tree e)
{
/* Constants have rank 0. */
if (is_gimple_min_invariant (e))
return 0;
/* SSA_NAME's have the rank of the expression they are the result
of.
For globals and uninitialized values, the rank is 0.
For function arguments, use the pre-setup rank.
For PHI nodes, stores, asm statements, etc, we use the rank of
the BB.
For simple operations, the rank is the maximum rank of any of
its operands, or the bb_rank, whichever is less.
I make no claims that this is optimal, however, it gives good
results. */
/* We make an exception to the normal ranking system to break
dependences of accumulator variables in loops. Suppose we
have a simple one-block loop containing:
x_1 = phi(x_0, x_2)
b = a + x_1
c = b + d
x_2 = c + e
As shown, each iteration of the calculation into x is fully
dependent upon the iteration before it. We would prefer to
see this in the form:
x_1 = phi(x_0, x_2)
b = a + d
c = b + e
x_2 = c + x_1
If the loop is unrolled, the calculations of b and c from
different iterations can be interleaved.
To obtain this result during reassociation, we bias the rank
of the phi definition x_1 upward, when it is recognized as an
accumulator pattern. The artificial rank causes it to be
added last, providing the desired independence. */
if (TREE_CODE (e) == SSA_NAME)
{
gimple stmt;
long rank;
int i, n;
tree op;
if (SSA_NAME_IS_DEFAULT_DEF (e))
return find_operand_rank (e);
stmt = SSA_NAME_DEF_STMT (e);
if (gimple_code (stmt) == GIMPLE_PHI)
return phi_rank (stmt);
if (!is_gimple_assign (stmt)
|| gimple_vdef (stmt))
return bb_rank[gimple_bb (stmt)->index];
/* If we already have a rank for this expression, use that. */
rank = find_operand_rank (e);
if (rank != -1)
return rank;
/* Otherwise, find the maximum rank for the operands. As an
exception, remove the bias from loop-carried phis when propagating
the rank so that dependent operations are not also biased. */
rank = 0;
if (gimple_assign_single_p (stmt))
{
tree rhs = gimple_assign_rhs1 (stmt);
n = TREE_OPERAND_LENGTH (rhs);
if (n == 0)
rank = propagate_rank (rank, rhs);
else
{
for (i = 0; i < n; i++)
{
op = TREE_OPERAND (rhs, i);
if (op != NULL_TREE)
rank = propagate_rank (rank, op);
}
}
}
else
{
n = gimple_num_ops (stmt);
for (i = 1; i < n; i++)
{
op = gimple_op (stmt, i);
gcc_assert (op);
rank = propagate_rank (rank, op);
}
}
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "Rank for ");
print_generic_expr (dump_file, e, 0);
fprintf (dump_file, " is %ld\n", (rank + 1));
}
/* Note the rank in the hashtable so we don't recompute it. */
insert_operand_rank (e, (rank + 1));
return (rank + 1);
}
/* Globals, etc, are rank 0 */
return 0;
}
/* We want integer ones to end up last no matter what, since they are
the ones we can do the most with. */
#define INTEGER_CONST_TYPE 1 << 3
#define FLOAT_CONST_TYPE 1 << 2
#define OTHER_CONST_TYPE 1 << 1
/* Classify an invariant tree into integer, float, or other, so that
we can sort them to be near other constants of the same type. */
static inline int
constant_type (tree t)
{
if (INTEGRAL_TYPE_P (TREE_TYPE (t)))
return INTEGER_CONST_TYPE;
else if (SCALAR_FLOAT_TYPE_P (TREE_TYPE (t)))
return FLOAT_CONST_TYPE;
else
return OTHER_CONST_TYPE;
}
/* qsort comparison function to sort operand entries PA and PB by rank
so that the sorted array is ordered by rank in decreasing order. */
static int
sort_by_operand_rank (const void *pa, const void *pb)
{
const operand_entry_t oea = *(const operand_entry_t *)pa;
const operand_entry_t oeb = *(const operand_entry_t *)pb;
/* It's nicer for optimize_expression if constants that are likely
to fold when added/multiplied//whatever are put next to each
other. Since all constants have rank 0, order them by type. */
if (oeb->rank == 0 && oea->rank == 0)
{
if (constant_type (oeb->op) != constant_type (oea->op))
return constant_type (oeb->op) - constant_type (oea->op);
else
/* To make sorting result stable, we use unique IDs to determine
order. */
return oeb->id - oea->id;
}
/* Lastly, make sure the versions that are the same go next to each
other. We use SSA_NAME_VERSION because it's stable. */
if ((oeb->rank - oea->rank == 0)
&& TREE_CODE (oea->op) == SSA_NAME
&& TREE_CODE (oeb->op) == SSA_NAME)
{
if (SSA_NAME_VERSION (oeb->op) != SSA_NAME_VERSION (oea->op))
return SSA_NAME_VERSION (oeb->op) - SSA_NAME_VERSION (oea->op);
else
return oeb->id - oea->id;
}
if (oeb->rank != oea->rank)
return oeb->rank - oea->rank;
else
return oeb->id - oea->id;
}
/* Add an operand entry to *OPS for the tree operand OP. */
static void
add_to_ops_vec (vec<operand_entry_t> *ops, tree op)
{
operand_entry_t oe = (operand_entry_t) pool_alloc (operand_entry_pool);
oe->op = op;
oe->rank = get_rank (op);
oe->id = next_operand_entry_id++;
oe->count = 1;
ops->safe_push (oe);
}
/* Add an operand entry to *OPS for the tree operand OP with repeat
count REPEAT. */
static void
add_repeat_to_ops_vec (vec<operand_entry_t> *ops, tree op,
HOST_WIDE_INT repeat)
{
operand_entry_t oe = (operand_entry_t) pool_alloc (operand_entry_pool);
oe->op = op;
oe->rank = get_rank (op);
oe->id = next_operand_entry_id++;
oe->count = repeat;
ops->safe_push (oe);
reassociate_stats.pows_encountered++;
}
/* Return true if STMT is reassociable operation containing a binary
operation with tree code CODE, and is inside LOOP. */
static bool
is_reassociable_op (gimple stmt, enum tree_code code, struct loop *loop)
{
basic_block bb = gimple_bb (stmt);
if (gimple_bb (stmt) == NULL)
return false;
if (!flow_bb_inside_loop_p (loop, bb))
return false;
if (is_gimple_assign (stmt)
&& gimple_assign_rhs_code (stmt) == code
&& has_single_use (gimple_assign_lhs (stmt)))
return true;
return false;
}
/* Given NAME, if NAME is defined by a unary operation OPCODE, return the
operand of the negate operation. Otherwise, return NULL. */
static tree
get_unary_op (tree name, enum tree_code opcode)
{
gimple stmt = SSA_NAME_DEF_STMT (name);
if (!is_gimple_assign (stmt))
return NULL_TREE;
if (gimple_assign_rhs_code (stmt) == opcode)
return gimple_assign_rhs1 (stmt);
return NULL_TREE;
}
/* If CURR and LAST are a pair of ops that OPCODE allows us to
eliminate through equivalences, do so, remove them from OPS, and
return true. Otherwise, return false. */
static bool
eliminate_duplicate_pair (enum tree_code opcode,
vec<operand_entry_t> *ops,
bool *all_done,
unsigned int i,
operand_entry_t curr,
operand_entry_t last)
{
/* If we have two of the same op, and the opcode is & |, min, or max,
we can eliminate one of them.
If we have two of the same op, and the opcode is ^, we can
eliminate both of them. */
if (last && last->op == curr->op)
{
switch (opcode)
{
case MAX_EXPR:
case MIN_EXPR:
case BIT_IOR_EXPR:
case BIT_AND_EXPR:
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "Equivalence: ");
print_generic_expr (dump_file, curr->op, 0);
fprintf (dump_file, " [&|minmax] ");
print_generic_expr (dump_file, last->op, 0);
fprintf (dump_file, " -> ");
print_generic_stmt (dump_file, last->op, 0);
}
ops->ordered_remove (i);
reassociate_stats.ops_eliminated ++;
return true;
case BIT_XOR_EXPR:
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "Equivalence: ");
print_generic_expr (dump_file, curr->op, 0);
fprintf (dump_file, " ^ ");
print_generic_expr (dump_file, last->op, 0);
fprintf (dump_file, " -> nothing\n");
}
reassociate_stats.ops_eliminated += 2;
if (ops->length () == 2)
{
ops->create (0);
add_to_ops_vec (ops, build_zero_cst (TREE_TYPE (last->op)));
*all_done = true;
}
else
{
ops->ordered_remove (i-1);
ops->ordered_remove (i-1);
}
return true;
default:
break;
}
}
return false;
}
static vec<tree> plus_negates;
/* If OPCODE is PLUS_EXPR, CURR->OP is a negate expression or a bitwise not
expression, look in OPS for a corresponding positive operation to cancel
it out. If we find one, remove the other from OPS, replace
OPS[CURRINDEX] with 0 or -1, respectively, and return true. Otherwise,
return false. */
static bool
eliminate_plus_minus_pair (enum tree_code opcode,
vec<operand_entry_t> *ops,
unsigned int currindex,
operand_entry_t curr)
{
tree negateop;
tree notop;
unsigned int i;
operand_entry_t oe;
if (opcode != PLUS_EXPR || TREE_CODE (curr->op) != SSA_NAME)
return false;
negateop = get_unary_op (curr->op, NEGATE_EXPR);
notop = get_unary_op (curr->op, BIT_NOT_EXPR);
if (negateop == NULL_TREE && notop == NULL_TREE)
return false;
/* Any non-negated version will have a rank that is one less than
the current rank. So once we hit those ranks, if we don't find
one, we can stop. */
for (i = currindex + 1;
ops->iterate (i, &oe)
&& oe->rank >= curr->rank - 1 ;
i++)
{
if (oe->op == negateop)
{
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "Equivalence: ");
print_generic_expr (dump_file, negateop, 0);
fprintf (dump_file, " + -");
print_generic_expr (dump_file, oe->op, 0);
fprintf (dump_file, " -> 0\n");
}
ops->ordered_remove (i);
add_to_ops_vec (ops, build_zero_cst (TREE_TYPE (oe->op)));
ops->ordered_remove (currindex);
reassociate_stats.ops_eliminated ++;
return true;
}
else if (oe->op == notop)
{
tree op_type = TREE_TYPE (oe->op);
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "Equivalence: ");
print_generic_expr (dump_file, notop, 0);
fprintf (dump_file, " + ~");
print_generic_expr (dump_file, oe->op, 0);
fprintf (dump_file, " -> -1\n");
}
ops->ordered_remove (i);
add_to_ops_vec (ops, build_int_cst_type (op_type, -1));
ops->ordered_remove (currindex);
reassociate_stats.ops_eliminated ++;
return true;
}
}
/* CURR->OP is a negate expr in a plus expr: save it for later
inspection in repropagate_negates(). */
if (negateop != NULL_TREE)
plus_negates.safe_push (curr->op);
return false;
}
/* If OPCODE is BIT_IOR_EXPR, BIT_AND_EXPR, and, CURR->OP is really a
bitwise not expression, look in OPS for a corresponding operand to
cancel it out. If we find one, remove the other from OPS, replace
OPS[CURRINDEX] with 0, and return true. Otherwise, return
false. */
static bool
eliminate_not_pairs (enum tree_code opcode,
vec<operand_entry_t> *ops,
unsigned int currindex,
operand_entry_t curr)
{
tree notop;
unsigned int i;
operand_entry_t oe;
if ((opcode != BIT_IOR_EXPR && opcode != BIT_AND_EXPR)
|| TREE_CODE (curr->op) != SSA_NAME)
return false;
notop = get_unary_op (curr->op, BIT_NOT_EXPR);
if (notop == NULL_TREE)
return false;
/* Any non-not version will have a rank that is one less than
the current rank. So once we hit those ranks, if we don't find
one, we can stop. */
for (i = currindex + 1;
ops->iterate (i, &oe)
&& oe->rank >= curr->rank - 1;
i++)
{
if (oe->op == notop)
{
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "Equivalence: ");
print_generic_expr (dump_file, notop, 0);
if (opcode == BIT_AND_EXPR)
fprintf (dump_file, " & ~");
else if (opcode == BIT_IOR_EXPR)
fprintf (dump_file, " | ~");
print_generic_expr (dump_file, oe->op, 0);
if (opcode == BIT_AND_EXPR)
fprintf (dump_file, " -> 0\n");
else if (opcode == BIT_IOR_EXPR)
fprintf (dump_file, " -> -1\n");
}
if (opcode == BIT_AND_EXPR)
oe->op = build_zero_cst (TREE_TYPE (oe->op));
else if (opcode == BIT_IOR_EXPR)
oe->op = build_all_ones_cst (TREE_TYPE (oe->op));
reassociate_stats.ops_eliminated += ops->length () - 1;
ops->truncate (0);
ops->quick_push (oe);
return true;
}
}
return false;
}
/* Use constant value that may be present in OPS to try to eliminate
operands. Note that this function is only really used when we've
eliminated ops for other reasons, or merged constants. Across
single statements, fold already does all of this, plus more. There
is little point in duplicating logic, so I've only included the
identities that I could ever construct testcases to trigger. */
static void
eliminate_using_constants (enum tree_code opcode,
vec<operand_entry_t> *ops)
{
operand_entry_t oelast = ops->last ();
tree type = TREE_TYPE (oelast->op);
if (oelast->rank == 0
&& (INTEGRAL_TYPE_P (type) || FLOAT_TYPE_P (type)))
{
switch (opcode)
{
case BIT_AND_EXPR:
if (integer_zerop (oelast->op))
{
if (ops->length () != 1)
{
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, "Found & 0, removing all other ops\n");
reassociate_stats.ops_eliminated += ops->length () - 1;
ops->truncate (0);
ops->quick_push (oelast);
return;
}
}
else if (integer_all_onesp (oelast->op))
{
if (ops->length () != 1)
{
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, "Found & -1, removing\n");
ops->pop ();
reassociate_stats.ops_eliminated++;
}
}
break;
case BIT_IOR_EXPR:
if (integer_all_onesp (oelast->op))
{
if (ops->length () != 1)
{
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, "Found | -1, removing all other ops\n");
reassociate_stats.ops_eliminated += ops->length () - 1;
ops->truncate (0);
ops->quick_push (oelast);
return;
}
}
else if (integer_zerop (oelast->op))
{
if (ops->length () != 1)
{
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, "Found | 0, removing\n");
ops->pop ();
reassociate_stats.ops_eliminated++;
}
}
break;
case MULT_EXPR:
if (integer_zerop (oelast->op)
|| (FLOAT_TYPE_P (type)
&& !HONOR_NANS (TYPE_MODE (type))
&& !HONOR_SIGNED_ZEROS (TYPE_MODE (type))
&& real_zerop (oelast->op)))
{
if (ops->length () != 1)
{
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, "Found * 0, removing all other ops\n");
reassociate_stats.ops_eliminated += ops->length () - 1;
ops->truncate (1);
ops->quick_push (oelast);
return;
}
}
else if (integer_onep (oelast->op)
|| (FLOAT_TYPE_P (type)
&& !HONOR_SNANS (TYPE_MODE (type))
&& real_onep (oelast->op)))
{
if (ops->length () != 1)
{
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, "Found * 1, removing\n");
ops->pop ();
reassociate_stats.ops_eliminated++;
return;
}
}
break;
case BIT_XOR_EXPR:
case PLUS_EXPR:
case MINUS_EXPR:
if (integer_zerop (oelast->op)
|| (FLOAT_TYPE_P (type)
&& (opcode == PLUS_EXPR || opcode == MINUS_EXPR)
&& fold_real_zero_addition_p (type, oelast->op,
opcode == MINUS_EXPR)))
{
if (ops->length () != 1)
{
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, "Found [|^+] 0, removing\n");
ops->pop ();
reassociate_stats.ops_eliminated++;
return;
}
}
break;
default:
break;
}
}
}
static void linearize_expr_tree (vec<operand_entry_t> *, gimple,
bool, bool);
/* Structure for tracking and counting operands. */
typedef struct oecount_s {
int cnt;
int id;
enum tree_code oecode;
tree op;
} oecount;
/* The heap for the oecount hashtable and the sorted list of operands. */
static vec<oecount> cvec;
/* Hash function for oecount. */
static hashval_t
oecount_hash (const void *p)
{
const oecount *c = &cvec[(size_t)p - 42];
return htab_hash_pointer (c->op) ^ (hashval_t)c->oecode;
}
/* Comparison function for oecount. */
static int
oecount_eq (const void *p1, const void *p2)
{
const oecount *c1 = &cvec[(size_t)p1 - 42];
const oecount *c2 = &cvec[(size_t)p2 - 42];
return (c1->oecode == c2->oecode
&& c1->op == c2->op);
}
/* Comparison function for qsort sorting oecount elements by count. */
static int
oecount_cmp (const void *p1, const void *p2)
{
const oecount *c1 = (const oecount *)p1;
const oecount *c2 = (const oecount *)p2;
if (c1->cnt != c2->cnt)
return c1->cnt - c2->cnt;
else
/* If counts are identical, use unique IDs to stabilize qsort. */
return c1->id - c2->id;
}
/* Return TRUE iff STMT represents a builtin call that raises OP
to some exponent. */
static bool
stmt_is_power_of_op (gimple stmt, tree op)
{
tree fndecl;
if (!is_gimple_call (stmt))
return false;
fndecl = gimple_call_fndecl (stmt);
if (!fndecl
|| DECL_BUILT_IN_CLASS (fndecl) != BUILT_IN_NORMAL)
return false;
switch (DECL_FUNCTION_CODE (gimple_call_fndecl (stmt)))
{
CASE_FLT_FN (BUILT_IN_POW):
CASE_FLT_FN (BUILT_IN_POWI):
return (operand_equal_p (gimple_call_arg (stmt, 0), op, 0));
default:
return false;
}
}
/* Given STMT which is a __builtin_pow* call, decrement its exponent
in place and return the result. Assumes that stmt_is_power_of_op
was previously called for STMT and returned TRUE. */
static HOST_WIDE_INT
decrement_power (gimple stmt)
{
REAL_VALUE_TYPE c, cint;
HOST_WIDE_INT power;
tree arg1;
switch (DECL_FUNCTION_CODE (gimple_call_fndecl (stmt)))
{
CASE_FLT_FN (BUILT_IN_POW):
arg1 = gimple_call_arg (stmt, 1);
c = TREE_REAL_CST (arg1);
power = real_to_integer (&c) - 1;
real_from_integer (&cint, VOIDmode, power, 0, 0);
gimple_call_set_arg (stmt, 1, build_real (TREE_TYPE (arg1), cint));
return power;
CASE_FLT_FN (BUILT_IN_POWI):
arg1 = gimple_call_arg (stmt, 1);
power = TREE_INT_CST_LOW (arg1) - 1;
gimple_call_set_arg (stmt, 1, build_int_cst (TREE_TYPE (arg1), power));
return power;
default:
gcc_unreachable ();
}
}
/* Find the single immediate use of STMT's LHS, and replace it
with OP. Remove STMT. If STMT's LHS is the same as *DEF,
replace *DEF with OP as well. */
static void
propagate_op_to_single_use (tree op, gimple stmt, tree *def)
{
tree lhs;
gimple use_stmt;
use_operand_p use;
gimple_stmt_iterator gsi;
if (is_gimple_call (stmt))
lhs = gimple_call_lhs (stmt);
else
lhs = gimple_assign_lhs (stmt);
gcc_assert (has_single_use (lhs));
single_imm_use (lhs, &use, &use_stmt);
if (lhs == *def)
*def = op;
SET_USE (use, op);
if (TREE_CODE (op) != SSA_NAME)
update_stmt (use_stmt);
gsi = gsi_for_stmt (stmt);
unlink_stmt_vdef (stmt);
gsi_remove (&gsi, true);
release_defs (stmt);
}
/* Walks the linear chain with result *DEF searching for an operation
with operand OP and code OPCODE removing that from the chain. *DEF
is updated if there is only one operand but no operation left. */
static void
zero_one_operation (tree *def, enum tree_code opcode, tree op)
{
gimple stmt = SSA_NAME_DEF_STMT (*def);
do
{
tree name;
if (opcode == MULT_EXPR
&& stmt_is_power_of_op (stmt, op))
{
if (decrement_power (stmt) == 1)
propagate_op_to_single_use (op, stmt, def);
return;
}
name = gimple_assign_rhs1 (stmt);
/* If this is the operation we look for and one of the operands
is ours simply propagate the other operand into the stmts
single use. */
if (gimple_assign_rhs_code (stmt) == opcode
&& (name == op
|| gimple_assign_rhs2 (stmt) == op))
{
if (name == op)
name = gimple_assign_rhs2 (stmt);
propagate_op_to_single_use (name, stmt, def);
return;
}
/* We might have a multiply of two __builtin_pow* calls, and
the operand might be hiding in the rightmost one. */
if (opcode == MULT_EXPR
&& gimple_assign_rhs_code (stmt) == opcode
&& TREE_CODE (gimple_assign_rhs2 (stmt)) == SSA_NAME
&& has_single_use (gimple_assign_rhs2 (stmt)))
{
gimple stmt2 = SSA_NAME_DEF_STMT (gimple_assign_rhs2 (stmt));
if (stmt_is_power_of_op (stmt2, op))
{
if (decrement_power (stmt2) == 1)
propagate_op_to_single_use (op, stmt2, def);
return;
}
}
/* Continue walking the chain. */
gcc_assert (name != op
&& TREE_CODE (name) == SSA_NAME);
stmt = SSA_NAME_DEF_STMT (name);
}
while (1);
}
/* Builds one statement performing OP1 OPCODE OP2 using TMPVAR for
the result. Places the statement after the definition of either
OP1 or OP2. Returns the new statement. */
static gimple
build_and_add_sum (tree type, tree op1, tree op2, enum tree_code opcode)
{
gimple op1def = NULL, op2def = NULL;
gimple_stmt_iterator gsi;
tree op;
gimple sum;
/* Create the addition statement. */
op = make_ssa_name (type, NULL);
sum = gimple_build_assign_with_ops (opcode, op, op1, op2);
/* Find an insertion place and insert. */
if (TREE_CODE (op1) == SSA_NAME)
op1def = SSA_NAME_DEF_STMT (op1);
if (TREE_CODE (op2) == SSA_NAME)
op2def = SSA_NAME_DEF_STMT (op2);
if ((!op1def || gimple_nop_p (op1def))
&& (!op2def || gimple_nop_p (op2def)))
{
gsi = gsi_after_labels (single_succ (ENTRY_BLOCK_PTR));
gsi_insert_before (&gsi, sum, GSI_NEW_STMT);
}
else if ((!op1def || gimple_nop_p (op1def))
|| (op2def && !gimple_nop_p (op2def)
&& stmt_dominates_stmt_p (op1def, op2def)))
{
if (gimple_code (op2def) == GIMPLE_PHI)
{
gsi = gsi_after_labels (gimple_bb (op2def));
gsi_insert_before (&gsi, sum, GSI_NEW_STMT);
}
else
{
if (!stmt_ends_bb_p (op2def))
{
gsi = gsi_for_stmt (op2def);
gsi_insert_after (&gsi, sum, GSI_NEW_STMT);
}
else
{
edge e;
edge_iterator ei;
FOR_EACH_EDGE (e, ei, gimple_bb (op2def)->succs)
if (e->flags & EDGE_FALLTHRU)
gsi_insert_on_edge_immediate (e, sum);
}
}
}
else
{
if (gimple_code (op1def) == GIMPLE_PHI)
{
gsi = gsi_after_labels (gimple_bb (op1def));
gsi_insert_before (&gsi, sum, GSI_NEW_STMT);
}
else
{
if (!stmt_ends_bb_p (op1def))
{
gsi = gsi_for_stmt (op1def);
gsi_insert_after (&gsi, sum, GSI_NEW_STMT);
}
else
{
edge e;
edge_iterator ei;
FOR_EACH_EDGE (e, ei, gimple_bb (op1def)->succs)
if (e->flags & EDGE_FALLTHRU)
gsi_insert_on_edge_immediate (e, sum);
}
}
}
update_stmt (sum);
return sum;
}
/* Perform un-distribution of divisions and multiplications.
A * X + B * X is transformed into (A + B) * X and A / X + B / X
to (A + B) / X for real X.
The algorithm is organized as follows.
- First we walk the addition chain *OPS looking for summands that
are defined by a multiplication or a real division. This results
in the candidates bitmap with relevant indices into *OPS.
- Second we build the chains of multiplications or divisions for
these candidates, counting the number of occurrences of (operand, code)
pairs in all of the candidates chains.
- Third we sort the (operand, code) pairs by number of occurrence and
process them starting with the pair with the most uses.
* For each such pair we walk the candidates again to build a
second candidate bitmap noting all multiplication/division chains
that have at least one occurrence of (operand, code).
* We build an alternate addition chain only covering these
candidates with one (operand, code) operation removed from their
multiplication/division chain.
* The first candidate gets replaced by the alternate addition chain
multiplied/divided by the operand.
* All candidate chains get disabled for further processing and
processing of (operand, code) pairs continues.
The alternate addition chains built are re-processed by the main
reassociation algorithm which allows optimizing a * x * y + b * y * x
to (a + b ) * x * y in one invocation of the reassociation pass. */
static bool
undistribute_ops_list (enum tree_code opcode,
vec<operand_entry_t> *ops, struct loop *loop)
{
unsigned int length = ops->length ();
operand_entry_t oe1;
unsigned i, j;
sbitmap candidates, candidates2;
unsigned nr_candidates, nr_candidates2;
sbitmap_iterator sbi0;
vec<operand_entry_t> *subops;
htab_t ctable;
bool changed = false;
int next_oecount_id = 0;
if (length <= 1
|| opcode != PLUS_EXPR)
return false;
/* Build a list of candidates to process. */
candidates = sbitmap_alloc (length);
bitmap_clear (candidates);
nr_candidates = 0;
FOR_EACH_VEC_ELT (*ops, i, oe1)
{
enum tree_code dcode;
gimple oe1def;
if (TREE_CODE (oe1->op) != SSA_NAME)
continue;
oe1def = SSA_NAME_DEF_STMT (oe1->op);
if (!is_gimple_assign (oe1def))
continue;
dcode = gimple_assign_rhs_code (oe1def);
if ((dcode != MULT_EXPR
&& dcode != RDIV_EXPR)
|| !is_reassociable_op (oe1def, dcode, loop))
continue;
bitmap_set_bit (candidates, i);
nr_candidates++;
}
if (nr_candidates < 2)
{
sbitmap_free (candidates);
return false;
}
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "searching for un-distribute opportunities ");
print_generic_expr (dump_file,
(*ops)[bitmap_first_set_bit (candidates)]->op, 0);
fprintf (dump_file, " %d\n", nr_candidates);
}
/* Build linearized sub-operand lists and the counting table. */
cvec.create (0);
ctable = htab_create (15, oecount_hash, oecount_eq, NULL);
/* ??? Macro arguments cannot have multi-argument template types in
them. This typedef is needed to workaround that limitation. */
typedef vec<operand_entry_t> vec_operand_entry_t_heap;
subops = XCNEWVEC (vec_operand_entry_t_heap, ops->length ());
EXECUTE_IF_SET_IN_BITMAP (candidates, 0, i, sbi0)
{
gimple oedef;
enum tree_code oecode;
unsigned j;
oedef = SSA_NAME_DEF_STMT ((*ops)[i]->op);
oecode = gimple_assign_rhs_code (oedef);
linearize_expr_tree (&subops[i], oedef,
associative_tree_code (oecode), false);
FOR_EACH_VEC_ELT (subops[i], j, oe1)
{
oecount c;
void **slot;
size_t idx;
c.oecode = oecode;
c.cnt = 1;
c.id = next_oecount_id++;
c.op = oe1->op;
cvec.safe_push (c);
idx = cvec.length () + 41;
slot = htab_find_slot (ctable, (void *)idx, INSERT);
if (!*slot)
{
*slot = (void *)idx;
}
else
{
cvec.pop ();
cvec[(size_t)*slot - 42].cnt++;
}
}
}
htab_delete (ctable);
/* Sort the counting table. */
cvec.qsort (oecount_cmp);
if (dump_file && (dump_flags & TDF_DETAILS))
{
oecount *c;
fprintf (dump_file, "Candidates:\n");
FOR_EACH_VEC_ELT (cvec, j, c)
{
fprintf (dump_file, " %u %s: ", c->cnt,
c->oecode == MULT_EXPR
? "*" : c->oecode == RDIV_EXPR ? "/" : "?");
print_generic_expr (dump_file, c->op, 0);
fprintf (dump_file, "\n");
}
}
/* Process the (operand, code) pairs in order of most occurence. */
candidates2 = sbitmap_alloc (length);
while (!cvec.is_empty ())
{
oecount *c = &cvec.last ();
if (c->cnt < 2)
break;
/* Now collect the operands in the outer chain that contain
the common operand in their inner chain. */
bitmap_clear (candidates2);
nr_candidates2 = 0;
EXECUTE_IF_SET_IN_BITMAP (candidates, 0, i, sbi0)
{
gimple oedef;
enum tree_code oecode;
unsigned j;
tree op = (*ops)[i]->op;
/* If we undistributed in this chain already this may be
a constant. */
if (TREE_CODE (op) != SSA_NAME)
continue;
oedef = SSA_NAME_DEF_STMT (op);
oecode = gimple_assign_rhs_code (oedef);
if (oecode != c->oecode)
continue;
FOR_EACH_VEC_ELT (subops[i], j, oe1)
{
if (oe1->op == c->op)
{
bitmap_set_bit (candidates2, i);
++nr_candidates2;
break;
}
}
}
if (nr_candidates2 >= 2)
{
operand_entry_t oe1, oe2;
gimple prod;
int first = bitmap_first_set_bit (candidates2);
/* Build the new addition chain. */
oe1 = (*ops)[first];
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "Building (");
print_generic_expr (dump_file, oe1->op, 0);
}
zero_one_operation (&oe1->op, c->oecode, c->op);
EXECUTE_IF_SET_IN_BITMAP (candidates2, first+1, i, sbi0)
{
gimple sum;
oe2 = (*ops)[i];
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, " + ");
print_generic_expr (dump_file, oe2->op, 0);
}
zero_one_operation (&oe2->op, c->oecode, c->op);
sum = build_and_add_sum (TREE_TYPE (oe1->op),
oe1->op, oe2->op, opcode);
oe2->op = build_zero_cst (TREE_TYPE (oe2->op));
oe2->rank = 0;
oe1->op = gimple_get_lhs (sum);
}
/* Apply the multiplication/division. */
prod = build_and_add_sum (TREE_TYPE (oe1->op),
oe1->op, c->op, c->oecode);
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, ") %s ", c->oecode == MULT_EXPR ? "*" : "/");
print_generic_expr (dump_file, c->op, 0);
fprintf (dump_file, "\n");
}
/* Record it in the addition chain and disable further
undistribution with this op. */
oe1->op = gimple_assign_lhs (prod);
oe1->rank = get_rank (oe1->op);
subops[first].release ();
changed = true;
}
cvec.pop ();
}
for (i = 0; i < ops->length (); ++i)
subops[i].release ();
free (subops);
cvec.release ();
sbitmap_free (candidates);
sbitmap_free (candidates2);
return changed;
}
/* If OPCODE is BIT_IOR_EXPR or BIT_AND_EXPR and CURR is a comparison
expression, examine the other OPS to see if any of them are comparisons
of the same values, which we may be able to combine or eliminate.
For example, we can rewrite (a < b) | (a == b) as (a <= b). */
static bool
eliminate_redundant_comparison (enum tree_code opcode,
vec<operand_entry_t> *ops,
unsigned int currindex,
operand_entry_t curr)
{
tree op1, op2;
enum tree_code lcode, rcode;
gimple def1, def2;
int i;
operand_entry_t oe;
if (opcode != BIT_IOR_EXPR && opcode != BIT_AND_EXPR)
return false;
/* Check that CURR is a comparison. */
if (TREE_CODE (curr->op) != SSA_NAME)
return false;
def1 = SSA_NAME_DEF_STMT (curr->op);
if (!is_gimple_assign (def1))
return false;
lcode = gimple_assign_rhs_code (def1);
if (TREE_CODE_CLASS (lcode) != tcc_comparison)
return false;
op1 = gimple_assign_rhs1 (def1);
op2 = gimple_assign_rhs2 (def1);
/* Now look for a similar comparison in the remaining OPS. */
for (i = currindex + 1; ops->iterate (i, &oe); i++)
{
tree t;
if (TREE_CODE (oe->op) != SSA_NAME)
continue;
def2 = SSA_NAME_DEF_STMT (oe->op);
if (!is_gimple_assign (def2))
continue;
rcode = gimple_assign_rhs_code (def2);
if (TREE_CODE_CLASS (rcode) != tcc_comparison)
continue;
/* If we got here, we have a match. See if we can combine the
two comparisons. */
if (opcode == BIT_IOR_EXPR)
t = maybe_fold_or_comparisons (lcode, op1, op2,
rcode, gimple_assign_rhs1 (def2),
gimple_assign_rhs2 (def2));
else
t = maybe_fold_and_comparisons (lcode, op1, op2,
rcode, gimple_assign_rhs1 (def2),
gimple_assign_rhs2 (def2));
if (!t)
continue;
/* maybe_fold_and_comparisons and maybe_fold_or_comparisons
always give us a boolean_type_node value back. If the original
BIT_AND_EXPR or BIT_IOR_EXPR was of a wider integer type,
we need to convert. */
if (!useless_type_conversion_p (TREE_TYPE (curr->op), TREE_TYPE (t)))
t = fold_convert (TREE_TYPE (curr->op), t);
if (TREE_CODE (t) != INTEGER_CST
&& !operand_equal_p (t, curr->op, 0))
{
enum tree_code subcode;
tree newop1, newop2;
if (!COMPARISON_CLASS_P (t))
continue;
extract_ops_from_tree (t, &subcode, &newop1, &newop2);
STRIP_USELESS_TYPE_CONVERSION (newop1);
STRIP_USELESS_TYPE_CONVERSION (newop2);
if (!is_gimple_val (newop1) || !is_gimple_val (newop2))
continue;
}
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "Equivalence: ");
print_generic_expr (dump_file, curr->op, 0);
fprintf (dump_file, " %s ", op_symbol_code (opcode));
print_generic_expr (dump_file, oe->op, 0);
fprintf (dump_file, " -> ");
print_generic_expr (dump_file, t, 0);
fprintf (dump_file, "\n");
}
/* Now we can delete oe, as it has been subsumed by the new combined
expression t. */
ops->ordered_remove (i);
reassociate_stats.ops_eliminated ++;
/* If t is the same as curr->op, we're done. Otherwise we must
replace curr->op with t. Special case is if we got a constant
back, in which case we add it to the end instead of in place of
the current entry. */
if (TREE_CODE (t) == INTEGER_CST)
{
ops->ordered_remove (currindex);
add_to_ops_vec (ops, t);
}
else if (!operand_equal_p (t, curr->op, 0))
{
gimple sum;
enum tree_code subcode;
tree newop1;
tree newop2;
gcc_assert (COMPARISON_CLASS_P (t));
extract_ops_from_tree (t, &subcode, &newop1, &newop2);
STRIP_USELESS_TYPE_CONVERSION (newop1);
STRIP_USELESS_TYPE_CONVERSION (newop2);
gcc_checking_assert (is_gimple_val (newop1)
&& is_gimple_val (newop2));
sum = build_and_add_sum (TREE_TYPE (t), newop1, newop2, subcode);
curr->op = gimple_get_lhs (sum);
}
return true;
}
return false;
}
/* Perform various identities and other optimizations on the list of
operand entries, stored in OPS. The tree code for the binary
operation between all the operands is OPCODE. */
static void
optimize_ops_list (enum tree_code opcode,
vec<operand_entry_t> *ops)
{
unsigned int length = ops->length ();
unsigned int i;
operand_entry_t oe;
operand_entry_t oelast = NULL;
bool iterate = false;
if (length == 1)
return;
oelast = ops->last ();
/* If the last two are constants, pop the constants off, merge them
and try the next two. */
if (oelast->rank == 0 && is_gimple_min_invariant (oelast->op))
{
operand_entry_t oelm1 = (*ops)[length - 2];
if (oelm1->rank == 0
&& is_gimple_min_invariant (oelm1->op)
&& useless_type_conversion_p (TREE_TYPE (oelm1->op),
TREE_TYPE (oelast->op)))
{
tree folded = fold_binary (opcode, TREE_TYPE (oelm1->op),
oelm1->op, oelast->op);
if (folded && is_gimple_min_invariant (folded))
{
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, "Merging constants\n");
ops->pop ();
ops->pop ();
add_to_ops_vec (ops, folded);
reassociate_stats.constants_eliminated++;
optimize_ops_list (opcode, ops);
return;
}
}
}
eliminate_using_constants (opcode, ops);
oelast = NULL;
for (i = 0; ops->iterate (i, &oe);)
{
bool done = false;
if (eliminate_not_pairs (opcode, ops, i, oe))
return;
if (eliminate_duplicate_pair (opcode, ops, &done, i, oe, oelast)
|| (!done && eliminate_plus_minus_pair (opcode, ops, i, oe))
|| (!done && eliminate_redundant_comparison (opcode, ops, i, oe)))
{
if (done)
return;
iterate = true;
oelast = NULL;
continue;
}
oelast = oe;
i++;
}
length = ops->length ();
oelast = ops->last ();
if (iterate)
optimize_ops_list (opcode, ops);
}
/* The following functions are subroutines to optimize_range_tests and allow
it to try to change a logical combination of comparisons into a range
test.
For example, both
X == 2 || X == 5 || X == 3 || X == 4
and
X >= 2 && X <= 5
are converted to
(unsigned) (X - 2) <= 3
For more information see comments above fold_test_range in fold-const.c,
this implementation is for GIMPLE. */
struct range_entry
{
tree exp;
tree low;
tree high;
bool in_p;
bool strict_overflow_p;
unsigned int idx, next;
};
/* This is similar to make_range in fold-const.c, but on top of
GIMPLE instead of trees. If EXP is non-NULL, it should be
an SSA_NAME and STMT argument is ignored, otherwise STMT
argument should be a GIMPLE_COND. */
static void
init_range_entry (struct range_entry *r, tree exp, gimple stmt)
{
int in_p;
tree low, high;
bool is_bool, strict_overflow_p;
r->exp = NULL_TREE;
r->in_p = false;
r->strict_overflow_p = false;
r->low = NULL_TREE;
r->high = NULL_TREE;
if (exp != NULL_TREE
&& (TREE_CODE (exp) != SSA_NAME || !INTEGRAL_TYPE_P (TREE_TYPE (exp))))
return;
/* Start with simply saying "EXP != 0" and then look at the code of EXP
and see if we can refine the range. Some of the cases below may not
happen, but it doesn't seem worth worrying about this. We "continue"
the outer loop when we've changed something; otherwise we "break"
the switch, which will "break" the while. */
low = exp ? build_int_cst (TREE_TYPE (exp), 0) : boolean_false_node;
high = low;
in_p = 0;
strict_overflow_p = false;
is_bool = false;
if (exp == NULL_TREE)
is_bool = true;
else if (TYPE_PRECISION (TREE_TYPE (exp)) == 1)
{
if (TYPE_UNSIGNED (TREE_TYPE (exp)))
is_bool = true;
else
return;
}
else if (TREE_CODE (TREE_TYPE (exp)) == BOOLEAN_TYPE)
is_bool = true;
while (1)
{
enum tree_code code;
tree arg0, arg1, exp_type;
tree nexp;
location_t loc;
if (exp != NULL_TREE)
{
if (TREE_CODE (exp) != SSA_NAME)
break;
stmt = SSA_NAME_DEF_STMT (exp);
if (!is_gimple_assign (stmt))
break;
code = gimple_assign_rhs_code (stmt);
arg0 = gimple_assign_rhs1 (stmt);
arg1 = gimple_assign_rhs2 (stmt);
exp_type = TREE_TYPE (exp);
}
else
{
code = gimple_cond_code (stmt);
arg0 = gimple_cond_lhs (stmt);
arg1 = gimple_cond_rhs (stmt);
exp_type = boolean_type_node;
}
if (TREE_CODE (arg0) != SSA_NAME)
break;
loc = gimple_location (stmt);
switch (code)
{
case BIT_NOT_EXPR:
if (TREE_CODE (TREE_TYPE (exp)) == BOOLEAN_TYPE
/* Ensure the range is either +[-,0], +[0,0],
-[-,0], -[0,0] or +[1,-], +[1,1], -[1,-] or
-[1,1]. If it is e.g. +[-,-] or -[-,-]
or similar expression of unconditional true or
false, it should not be negated. */
&& ((high && integer_zerop (high))
|| (low && integer_onep (low))))
{
in_p = !in_p;
exp = arg0;
continue;
}
break;
case SSA_NAME:
exp = arg0;
continue;
CASE_CONVERT:
if (is_bool)
goto do_default;
if (TYPE_PRECISION (TREE_TYPE (arg0)) == 1)
{
if (TYPE_UNSIGNED (TREE_TYPE (arg0)))
is_bool = true;
else
return;
}
else if (TREE_CODE (TREE_TYPE (arg0)) == BOOLEAN_TYPE)
is_bool = true;
goto do_default;
case EQ_EXPR:
case NE_EXPR:
case LT_EXPR:
case LE_EXPR:
case GE_EXPR:
case GT_EXPR:
is_bool = true;
/* FALLTHRU */
default:
if (!is_bool)
return;
do_default:
nexp = make_range_step (loc, code, arg0, arg1, exp_type,
&low, &high, &in_p,
&strict_overflow_p);
if (nexp != NULL_TREE)
{
exp = nexp;
gcc_assert (TREE_CODE (exp) == SSA_NAME);
continue;
}
break;
}
break;
}
if (is_bool)
{
r->exp = exp;
r->in_p = in_p;
r->low = low;
r->high = high;
r->strict_overflow_p = strict_overflow_p;
}
}
/* Comparison function for qsort. Sort entries
without SSA_NAME exp first, then with SSA_NAMEs sorted
by increasing SSA_NAME_VERSION, and for the same SSA_NAMEs
by increasing ->low and if ->low is the same, by increasing
->high. ->low == NULL_TREE means minimum, ->high == NULL_TREE
maximum. */
static int
range_entry_cmp (const void *a, const void *b)
{
const struct range_entry *p = (const struct range_entry *) a;
const struct range_entry *q = (const struct range_entry *) b;
if (p->exp != NULL_TREE && TREE_CODE (p->exp) == SSA_NAME)
{
if (q->exp != NULL_TREE && TREE_CODE (q->exp) == SSA_NAME)
{
/* Group range_entries for the same SSA_NAME together. */
if (SSA_NAME_VERSION (p->exp) < SSA_NAME_VERSION (q->exp))
return -1;
else if (SSA_NAME_VERSION (p->exp) > SSA_NAME_VERSION (q->exp))
return 1;
/* If ->low is different, NULL low goes first, then by
ascending low. */
if (p->low != NULL_TREE)
{
if (q->low != NULL_TREE)
{
tree tem = fold_binary (LT_EXPR, boolean_type_node,
p->low, q->low);
if (tem && integer_onep (tem))
return -1;
tem = fold_binary (GT_EXPR, boolean_type_node,
p->low, q->low);
if (tem && integer_onep (tem))
return 1;
}
else
return 1;
}
else if (q->low != NULL_TREE)
return -1;
/* If ->high is different, NULL high goes last, before that by
ascending high. */
if (p->high != NULL_TREE)
{
if (q->high != NULL_TREE)
{
tree tem = fold_binary (LT_EXPR, boolean_type_node,
p->high, q->high);
if (tem && integer_onep (tem))
return -1;
tem = fold_binary (GT_EXPR, boolean_type_node,
p->high, q->high);
if (tem && integer_onep (tem))
return 1;
}
else
return -1;
}
else if (q->high != NULL_TREE)
return 1;
/* If both ranges are the same, sort below by ascending idx. */
}
else
return 1;
}
else if (q->exp != NULL_TREE && TREE_CODE (q->exp) == SSA_NAME)
return -1;
if (p->idx < q->idx)
return -1;
else
{
gcc_checking_assert (p->idx > q->idx);
return 1;
}
}
/* Helper routine of optimize_range_test.
[EXP, IN_P, LOW, HIGH, STRICT_OVERFLOW_P] is a merged range for
RANGE and OTHERRANGE through OTHERRANGE + COUNT - 1 ranges,
OPCODE and OPS are arguments of optimize_range_tests. Return
true if the range merge has been successful.
If OPCODE is ERROR_MARK, this is called from within
maybe_optimize_range_tests and is performing inter-bb range optimization.
Changes should be then performed right away, and whether an op is
BIT_AND_EXPR or BIT_IOR_EXPR is found in oe->rank. */
static bool
update_range_test (struct range_entry *range, struct range_entry *otherrange,
unsigned int count, enum tree_code opcode,
vec<operand_entry_t> *ops, tree exp, bool in_p,
tree low, tree high, bool strict_overflow_p)
{
operand_entry_t oe = (*ops)[range->idx];
tree op = oe->op;
gimple stmt = op ? SSA_NAME_DEF_STMT (op) : last_stmt (BASIC_BLOCK (oe->id));
location_t loc = gimple_location (stmt);
tree optype = op ? TREE_TYPE (op) : boolean_type_node;
tree tem = build_range_check (loc, optype, exp, in_p, low, high);
enum warn_strict_overflow_code wc = WARN_STRICT_OVERFLOW_COMPARISON;
gimple_stmt_iterator gsi;
if (tem == NULL_TREE)
return false;
if (strict_overflow_p && issue_strict_overflow_warning (wc))
warning_at (loc, OPT_Wstrict_overflow,
"assuming signed overflow does not occur "
"when simplifying range test");
if (dump_file && (dump_flags & TDF_DETAILS))
{
struct range_entry *r;
fprintf (dump_file, "Optimizing range tests ");
print_generic_expr (dump_file, range->exp, 0);
fprintf (dump_file, " %c[", range->in_p ? '+' : '-');
print_generic_expr (dump_file, range->low, 0);
fprintf (dump_file, ", ");
print_generic_expr (dump_file, range->high, 0);
fprintf (dump_file, "]");
for (r = otherrange; r < otherrange + count; r++)
{
fprintf (dump_file, " and %c[", r->in_p ? '+' : '-');
print_generic_expr (dump_file, r->low, 0);
fprintf (dump_file, ", ");
print_generic_expr (dump_file, r->high, 0);
fprintf (dump_file, "]");
}
fprintf (dump_file, "\n into ");
print_generic_expr (dump_file, tem, 0);
fprintf (dump_file, "\n");
}
if (opcode == BIT_IOR_EXPR
|| (opcode == ERROR_MARK && oe->rank == BIT_IOR_EXPR))
tem = invert_truthvalue_loc (loc, tem);
tem = fold_convert_loc (loc, optype, tem);
gsi = gsi_for_stmt (stmt);
/* In rare cases range->exp can be equal to lhs of stmt.
In that case we have to insert after the stmt rather then before
it. */
if (op == range->exp)
tem = force_gimple_operand_gsi (&gsi, tem, true, NULL_TREE, false,
GSI_SAME_STMT);
else
tem = force_gimple_operand_gsi (&gsi, tem, true, NULL_TREE, true,
GSI_SAME_STMT);
/* If doing inter-bb range test optimization, update the
stmts immediately. Start with changing the first range test
immediate use to the new value (TEM), or, if the first range
test is a GIMPLE_COND stmt, change that condition. */
if (opcode == ERROR_MARK)
{
if (op)
{
imm_use_iterator iter;
use_operand_p use_p;
gimple use_stmt;
FOR_EACH_IMM_USE_STMT (use_stmt, iter, op)
{
if (is_gimple_debug (use_stmt))
continue;
FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
SET_USE (use_p, tem);
update_stmt (use_stmt);
}
}
else
{
gimple_cond_set_code (stmt, NE_EXPR);
gimple_cond_set_lhs (stmt, tem);
gimple_cond_set_rhs (stmt, boolean_false_node);
update_stmt (stmt);
}
}
oe->op = tem;
range->exp = exp;
range->low = low;
range->high = high;
range->in_p = in_p;
range->strict_overflow_p = false;
for (range = otherrange; range < otherrange + count; range++)
{
oe = (*ops)[range->idx];
/* Now change all the other range test immediate uses, so that
those tests will be optimized away. */
if (opcode == ERROR_MARK)
{
if (oe->op)
{
imm_use_iterator iter;
use_operand_p use_p;
gimple use_stmt;
FOR_EACH_IMM_USE_STMT (use_stmt, iter, oe->op)
{
if (is_gimple_debug (use_stmt))
continue;
/* If imm use of _8 is a statement like _7 = _8 | _9;,
adjust it into _7 = _9;. */
if (is_gimple_assign (use_stmt)
&& gimple_assign_rhs_code (use_stmt) == oe->rank)
{
tree expr = NULL_TREE;
if (oe->op == gimple_assign_rhs1 (use_stmt))
expr = gimple_assign_rhs2 (use_stmt);
else if (oe->op == gimple_assign_rhs2 (use_stmt))
expr = gimple_assign_rhs1 (use_stmt);
if (expr
&& expr != oe->op
&& TREE_CODE (expr) == SSA_NAME)
{
gimple_stmt_iterator gsi2 = gsi_for_stmt (use_stmt);
gimple_assign_set_rhs_with_ops (&gsi2, SSA_NAME,
expr, NULL_TREE);
update_stmt (use_stmt);
continue;
}
}
/* If imm use of _8 is a statement like _7 = (int) _8;,
adjust it into _7 = 0; or _7 = 1;. */
if (gimple_assign_cast_p (use_stmt)
&& oe->op == gimple_assign_rhs1 (use_stmt))
{
tree lhs = gimple_assign_lhs (use_stmt);
if (INTEGRAL_TYPE_P (TREE_TYPE (lhs)))
{
gimple_stmt_iterator gsi2
= gsi_for_stmt (use_stmt);
tree expr = build_int_cst (TREE_TYPE (lhs),
oe->rank == BIT_IOR_EXPR
? 0 : 1);
gimple_assign_set_rhs_with_ops (&gsi2,
INTEGER_CST,
expr, NULL_TREE);
update_stmt (use_stmt);
continue;
}
}
/* Otherwise replace the use with 0 or 1. */
FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
SET_USE (use_p,
build_int_cst (TREE_TYPE (oe->op),
oe->rank == BIT_IOR_EXPR
? 0 : 1));
update_stmt (use_stmt);
}
}
else
{
/* If range test was a GIMPLE_COND, simply change it
into an always false or always true condition. */
stmt = last_stmt (BASIC_BLOCK (oe->id));
if (oe->rank == BIT_IOR_EXPR)
gimple_cond_make_false (stmt);
else
gimple_cond_make_true (stmt);
update_stmt (stmt);
}
}
oe->op = error_mark_node;
range->exp = NULL_TREE;
}
return true;
}
/* Optimize range tests, similarly how fold_range_test optimizes
it on trees. The tree code for the binary
operation between all the operands is OPCODE.
If OPCODE is ERROR_MARK, optimize_range_tests is called from within
maybe_optimize_range_tests for inter-bb range optimization.
In that case if oe->op is NULL, oe->id is bb->index whose
GIMPLE_COND is && or ||ed into the test, and oe->rank says
the actual opcode. */
static void
optimize_range_tests (enum tree_code opcode,
vec<operand_entry_t> *ops)
{
unsigned int length = ops->length (), i, j, first;
operand_entry_t oe;
struct range_entry *ranges;
bool any_changes = false;
if (length == 1)
return;
ranges = XNEWVEC (struct range_entry, length);
for (i = 0; i < length; i++)
{
oe = (*ops)[i];
ranges[i].idx = i;
init_range_entry (ranges + i, oe->op,
oe->op ? NULL : last_stmt (BASIC_BLOCK (oe->id)));
/* For | invert it now, we will invert it again before emitting
the optimized expression. */
if (opcode == BIT_IOR_EXPR
|| (opcode == ERROR_MARK && oe->rank == BIT_IOR_EXPR))
ranges[i].in_p = !ranges[i].in_p;
}
qsort (ranges, length, sizeof (*ranges), range_entry_cmp);
for (i = 0; i < length; i++)
if (ranges[i].exp != NULL_TREE && TREE_CODE (ranges[i].exp) == SSA_NAME)
break;
/* Try to merge ranges. */
for (first = i; i < length; i++)
{
tree low = ranges[i].low;
tree high = ranges[i].high;
int in_p = ranges[i].in_p;
bool strict_overflow_p = ranges[i].strict_overflow_p;
int update_fail_count = 0;
for (j = i + 1; j < length; j++)
{
if (ranges[i].exp != ranges[j].exp)
break;
if (!merge_ranges (&in_p, &low, &high, in_p, low, high,
ranges[j].in_p, ranges[j].low, ranges[j].high))
break;
strict_overflow_p |= ranges[j].strict_overflow_p;
}
if (j == i + 1)
continue;
if (update_range_test (ranges + i, ranges + i + 1, j - i - 1, opcode,
ops, ranges[i].exp, in_p, low, high,
strict_overflow_p))
{
i = j - 1;
any_changes = true;
}
/* Avoid quadratic complexity if all merge_ranges calls would succeed,
while update_range_test would fail. */
else if (update_fail_count == 64)
i = j - 1;
else
++update_fail_count;
}
/* Optimize X == CST1 || X == CST2
if popcount (CST1 ^ CST2) == 1 into
(X & ~(CST1 ^ CST2)) == (CST1 & ~(CST1 ^ CST2)).
Similarly for ranges. E.g.
X != 2 && X != 3 && X != 10 && X != 11
will be transformed by the above loop into
(X - 2U) <= 1U && (X - 10U) <= 1U
and this loop can transform that into
((X & ~8) - 2U) <= 1U. */
for (i = first; i < length; i++)
{
tree lowi, highi, lowj, highj, type, lowxor, highxor, tem, exp;
if (ranges[i].exp == NULL_TREE || ranges[i].in_p)
continue;
type = TREE_TYPE (ranges[i].exp);
if (!INTEGRAL_TYPE_P (type))
continue;
lowi = ranges[i].low;
if (lowi == NULL_TREE)
lowi = TYPE_MIN_VALUE (type);
highi = ranges[i].high;
if (highi == NULL_TREE)
continue;
for (j = i + 1; j < length && j < i + 64; j++)
{
if (ranges[j].exp == NULL_TREE)
continue;
if (ranges[i].exp != ranges[j].exp)
break;
if (ranges[j].in_p)
continue;
lowj = ranges[j].low;
if (lowj == NULL_TREE)
continue;
highj = ranges[j].high;
if (highj == NULL_TREE)
highj = TYPE_MAX_VALUE (type);
tem = fold_binary (GT_EXPR, boolean_type_node,
lowj, highi);
if (tem == NULL_TREE || !integer_onep (tem))
continue;
lowxor = fold_binary (BIT_XOR_EXPR, type, lowi, lowj);
if (lowxor == NULL_TREE || TREE_CODE (lowxor) != INTEGER_CST)
continue;
gcc_checking_assert (!integer_zerop (lowxor));
tem = fold_binary (MINUS_EXPR, type, lowxor,
build_int_cst (type, 1));
if (tem == NULL_TREE)
continue;
tem = fold_binary (BIT_AND_EXPR, type, lowxor, tem);
if (tem == NULL_TREE || !integer_zerop (tem))
continue;
highxor = fold_binary (BIT_XOR_EXPR, type, highi, highj);
if (!tree_int_cst_equal (lowxor, highxor))
continue;
tem = fold_build1 (BIT_NOT_EXPR, type, lowxor);
exp = fold_build2 (BIT_AND_EXPR, type, ranges[i].exp, tem);
lowj = fold_build2 (BIT_AND_EXPR, type, lowi, tem);
highj = fold_build2 (BIT_AND_EXPR, type, highi, tem);
if (update_range_test (ranges + i, ranges + j, 1, opcode, ops, exp,
ranges[i].in_p, lowj, highj,
ranges[i].strict_overflow_p
|| ranges[j].strict_overflow_p))
{
any_changes = true;
break;
}
}
}
if (any_changes && opcode != ERROR_MARK)
{
j = 0;
FOR_EACH_VEC_ELT (*ops, i, oe)
{
if (oe->op == error_mark_node)
continue;
else if (i != j)
(*ops)[j] = oe;
j++;
}
ops->truncate (j);
}
XDELETEVEC (ranges);
}
/* Return true if STMT is a cast like:
<bb N>:
...
_123 = (int) _234;
<bb M>:
# _345 = PHI <_123(N), 1(...), 1(...)>
where _234 has bool type, _123 has single use and
bb N has a single successor M. This is commonly used in
the last block of a range test. */
static bool
final_range_test_p (gimple stmt)
{
basic_block bb, rhs_bb;
edge e;
tree lhs, rhs;
use_operand_p use_p;
gimple use_stmt;
if (!gimple_assign_cast_p (stmt))
return false;
bb = gimple_bb (stmt);
if (!single_succ_p (bb))
return false;
e = single_succ_edge (bb);
if (e->flags & EDGE_COMPLEX)
return false;
lhs = gimple_assign_lhs (stmt);
rhs = gimple_assign_rhs1 (stmt);
if (!INTEGRAL_TYPE_P (TREE_TYPE (lhs))
|| TREE_CODE (rhs) != SSA_NAME
|| TREE_CODE (TREE_TYPE (rhs)) != BOOLEAN_TYPE)
return false;
/* Test whether lhs is consumed only by a PHI in the only successor bb. */
if (!single_imm_use (lhs, &use_p, &use_stmt))
return false;
if (gimple_code (use_stmt) != GIMPLE_PHI
|| gimple_bb (use_stmt) != e->dest)
return false;
/* And that the rhs is defined in the same loop. */
rhs_bb = gimple_bb (SSA_NAME_DEF_STMT (rhs));
if (rhs_bb == NULL
|| !flow_bb_inside_loop_p (loop_containing_stmt (stmt), rhs_bb))
return false;
return true;
}
/* Return true if BB is suitable basic block for inter-bb range test
optimization. If BACKWARD is true, BB should be the only predecessor
of TEST_BB, and *OTHER_BB is either NULL and filled by the routine,
or compared with to find a common basic block to which all conditions
branch to if true resp. false. If BACKWARD is false, TEST_BB should
be the only predecessor of BB. */
static bool
suitable_cond_bb (basic_block bb, basic_block test_bb, basic_block *other_bb,
bool backward)
{
edge_iterator ei, ei2;
edge e, e2;
gimple stmt;
gimple_stmt_iterator gsi;
bool other_edge_seen = false;
bool is_cond;
if (test_bb == bb)
return false;
/* Check last stmt first. */
stmt = last_stmt (bb);
if (stmt == NULL
|| (gimple_code (stmt) != GIMPLE_COND
&& (backward || !final_range_test_p (stmt)))
|| gimple_visited_p (stmt)
|| stmt_could_throw_p (stmt)
|| *other_bb == bb)
return false;
is_cond = gimple_code (stmt) == GIMPLE_COND;
if (is_cond)
{
/* If last stmt is GIMPLE_COND, verify that one of the succ edges
goes to the next bb (if BACKWARD, it is TEST_BB), and the other
to *OTHER_BB (if not set yet, try to find it out). */
if (EDGE_COUNT (bb->succs) != 2)
return false;
FOR_EACH_EDGE (e, ei, bb->succs)
{
if (!(e->flags & (EDGE_TRUE_VALUE | EDGE_FALSE_VALUE)))
return false;
if (e->dest == test_bb)
{
if (backward)
continue;
else
return false;
}
if (e->dest == bb)
return false;
if (*other_bb == NULL)
{
FOR_EACH_EDGE (e2, ei2, test_bb->succs)
if (!(e2->flags & (EDGE_TRUE_VALUE | EDGE_FALSE_VALUE)))
return false;
else if (e->dest == e2->dest)
*other_bb = e->dest;
if (*other_bb == NULL)
return false;
}
if (e->dest == *other_bb)
other_edge_seen = true;
else if (backward)
return false;
}
if (*other_bb == NULL || !other_edge_seen)
return false;
}
else if (single_succ (bb) != *other_bb)
return false;
/* Now check all PHIs of *OTHER_BB. */
e = find_edge (bb, *other_bb);
e2 = find_edge (test_bb, *other_bb);
for (gsi = gsi_start_phis (e->dest); !gsi_end_p (gsi); gsi_next (&gsi))
{
gimple phi = gsi_stmt (gsi);
/* If both BB and TEST_BB end with GIMPLE_COND, all PHI arguments
corresponding to BB and TEST_BB predecessor must be the same. */
if (!operand_equal_p (gimple_phi_arg_def (phi, e->dest_idx),
gimple_phi_arg_def (phi, e2->dest_idx), 0))
{
/* Otherwise, if one of the blocks doesn't end with GIMPLE_COND,
one of the PHIs should have the lhs of the last stmt in
that block as PHI arg and that PHI should have 0 or 1
corresponding to it in all other range test basic blocks
considered. */
if (!is_cond)
{
if (gimple_phi_arg_def (phi, e->dest_idx)
== gimple_assign_lhs (stmt)
&& (integer_zerop (gimple_phi_arg_def (phi, e2->dest_idx))
|| integer_onep (gimple_phi_arg_def (phi,
e2->dest_idx))))
continue;
}
else
{
gimple test_last = last_stmt (test_bb);
if (gimple_code (test_last) != GIMPLE_COND
&& gimple_phi_arg_def (phi, e2->dest_idx)
== gimple_assign_lhs (test_last)
&& (integer_zerop (gimple_phi_arg_def (phi, e->dest_idx))
|| integer_onep (gimple_phi_arg_def (phi, e->dest_idx))))
continue;
}
return false;
}
}
return true;
}
/* Return true if BB doesn't have side-effects that would disallow
range test optimization, all SSA_NAMEs set in the bb are consumed
in the bb and there are no PHIs. */
static bool
no_side_effect_bb (basic_block bb)
{
gimple_stmt_iterator gsi;
gimple last;
if (!gimple_seq_empty_p (phi_nodes (bb)))
return false;
last = last_stmt (bb);
for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
{
gimple stmt = gsi_stmt (gsi);
tree lhs;
imm_use_iterator imm_iter;
use_operand_p use_p;
if (is_gimple_debug (stmt))
continue;
if (gimple_has_side_effects (stmt))
return false;
if (stmt == last)
return true;
if (!is_gimple_assign (stmt))
return false;
lhs = gimple_assign_lhs (stmt);
if (TREE_CODE (lhs) != SSA_NAME)
return false;
if (gimple_assign_rhs_could_trap_p (stmt))
return false;
FOR_EACH_IMM_USE_FAST (use_p, imm_iter, lhs)
{
gimple use_stmt = USE_STMT (use_p);
if (is_gimple_debug (use_stmt))
continue;
if (gimple_bb (use_stmt) != bb)
return false;
}
}
return false;
}
/* If VAR is set by CODE (BIT_{AND,IOR}_EXPR) which is reassociable,
return true and fill in *OPS recursively. */
static bool
get_ops (tree var, enum tree_code code, vec<operand_entry_t> *ops,
struct loop *loop)
{
gimple stmt = SSA_NAME_DEF_STMT (var);
tree rhs[2];
int i;
if (!is_reassociable_op (stmt, code, loop))
return false;
rhs[0] = gimple_assign_rhs1 (stmt);
rhs[1] = gimple_assign_rhs2 (stmt);
gimple_set_visited (stmt, true);
for (i = 0; i < 2; i++)
if (TREE_CODE (rhs[i]) == SSA_NAME
&& !get_ops (rhs[i], code, ops, loop)
&& has_single_use (rhs[i]))
{
operand_entry_t oe = (operand_entry_t) pool_alloc (operand_entry_pool);
oe->op = rhs[i];
oe->rank = code;
oe->id = 0;
oe->count = 1;
ops->safe_push (oe);
}
return true;
}
/* Inter-bb range test optimization. */
static void
maybe_optimize_range_tests (gimple stmt)
{
basic_block first_bb = gimple_bb (stmt);
basic_block last_bb = first_bb;
basic_block other_bb = NULL;
basic_block bb;
edge_iterator ei;
edge e;
vec<operand_entry_t> ops = vNULL;
/* Consider only basic blocks that end with GIMPLE_COND or
a cast statement satisfying final_range_test_p. All
but the last bb in the first_bb .. last_bb range
should end with GIMPLE_COND. */
if (gimple_code (stmt) == GIMPLE_COND)
{
if (EDGE_COUNT (first_bb->succs) != 2)
return;
}
else if (final_range_test_p (stmt))
other_bb = single_succ (first_bb);
else
return;
if (stmt_could_throw_p (stmt))
return;
/* As relative ordering of post-dominator sons isn't fixed,
maybe_optimize_range_tests can be called first on any
bb in the range we want to optimize. So, start searching
backwards, if first_bb can be set to a predecessor. */
while (single_pred_p (first_bb))
{
basic_block pred_bb = single_pred (first_bb);
if (!suitable_cond_bb (pred_bb, first_bb, &other_bb, true))
break;
if (!no_side_effect_bb (first_bb))
break;
first_bb = pred_bb;
}
/* If first_bb is last_bb, other_bb hasn't been computed yet.
Before starting forward search in last_bb successors, find
out the other_bb. */
if (first_bb == last_bb)
{
other_bb = NULL;
/* As non-GIMPLE_COND last stmt always terminates the range,
if forward search didn't discover anything, just give up. */
if (gimple_code (stmt) != GIMPLE_COND)
return;
/* Look at both successors. Either it ends with a GIMPLE_COND
and satisfies suitable_cond_bb, or ends with a cast and
other_bb is that cast's successor. */
FOR_EACH_EDGE (e, ei, first_bb->succs)
if (!(e->flags & (EDGE_TRUE_VALUE | EDGE_FALSE_VALUE))
|| e->dest == first_bb)
return;
else if (single_pred_p (e->dest))
{
stmt = last_stmt (e->dest);
if (stmt
&& gimple_code (stmt) == GIMPLE_COND
&& EDGE_COUNT (e->dest->succs) == 2)
{
if (suitable_cond_bb (first_bb, e->dest, &other_bb, true))
break;
else
other_bb = NULL;
}
else if (stmt
&& final_range_test_p (stmt)
&& find_edge (first_bb, single_succ (e->dest)))
{
other_bb = single_succ (e->dest);
if (other_bb == first_bb)
other_bb = NULL;
}
}
if (other_bb == NULL)
return;
}
/* Now do the forward search, moving last_bb to successor bbs
that aren't other_bb. */
while (EDGE_COUNT (last_bb->succs) == 2)
{
FOR_EACH_EDGE (e, ei, last_bb->succs)
if (e->dest != other_bb)
break;
if (e == NULL)
break;
if (!single_pred_p (e->dest))
break;
if (!suitable_cond_bb (e->dest, last_bb, &other_bb, false))
break;
if (!no_side_effect_bb (e->dest))
break;
last_bb = e->dest;
}
if (first_bb == last_bb)
return;
/* Here basic blocks first_bb through last_bb's predecessor
end with GIMPLE_COND, all of them have one of the edges to
other_bb and another to another block in the range,
all blocks except first_bb don't have side-effects and
last_bb ends with either GIMPLE_COND, or cast satisfying
final_range_test_p. */
for (bb = last_bb; ; bb = single_pred (bb))
{
enum tree_code code;
tree lhs, rhs;
e = find_edge (bb, other_bb);
stmt = last_stmt (bb);
gimple_set_visited (stmt, true);
if (gimple_code (stmt) != GIMPLE_COND)
{
use_operand_p use_p;
gimple phi;
edge e2;
unsigned int d;
lhs = gimple_assign_lhs (stmt);
rhs = gimple_assign_rhs1 (stmt);
gcc_assert (bb == last_bb);
/* stmt is
_123 = (int) _234;
followed by:
<bb M>:
# _345 = PHI <_123(N), 1(...), 1(...)>
or 0 instead of 1. If it is 0, the _234
range test is anded together with all the
other range tests, if it is 1, it is ored with
them. */
single_imm_use (lhs, &use_p, &phi);
gcc_assert (gimple_code (phi) == GIMPLE_PHI);
e2 = find_edge (first_bb, other_bb);
d = e2->dest_idx;
gcc_assert (gimple_phi_arg_def (phi, e->dest_idx) == lhs);
if (integer_zerop (gimple_phi_arg_def (phi, d)))
code = BIT_AND_EXPR;
else
{
gcc_checking_assert (integer_onep (gimple_phi_arg_def (phi, d)));
code = BIT_IOR_EXPR;
}
/* If _234 SSA_NAME_DEF_STMT is
_234 = _567 | _789;
(or &, corresponding to 1/0 in the phi arguments,
push into ops the individual range test arguments
of the bitwise or resp. and, recursively. */
if (!get_ops (rhs, code, &ops,
loop_containing_stmt (stmt))
&& has_single_use (rhs))
{
/* Otherwise, push the _234 range test itself. */
operand_entry_t oe
= (operand_entry_t) pool_alloc (operand_entry_pool);
oe->op = rhs;
oe->rank = code;
oe->id = 0;
oe->count = 1;
ops.safe_push (oe);
}
continue;
}
/* Otherwise stmt is GIMPLE_COND. */
code = gimple_cond_code (stmt);
lhs = gimple_cond_lhs (stmt);
rhs = gimple_cond_rhs (stmt);
if (TREE_CODE (lhs) == SSA_NAME
&& INTEGRAL_TYPE_P (TREE_TYPE (lhs))
&& ((code != EQ_EXPR && code != NE_EXPR)
|| rhs != boolean_false_node
/* Either push into ops the individual bitwise
or resp. and operands, depending on which
edge is other_bb. */
|| !get_ops (lhs, (((e->flags & EDGE_TRUE_VALUE) == 0)
^ (code == EQ_EXPR))
? BIT_AND_EXPR : BIT_IOR_EXPR, &ops,
loop_containing_stmt (stmt))))
{
/* Or push the GIMPLE_COND stmt itself. */
operand_entry_t oe
= (operand_entry_t) pool_alloc (operand_entry_pool);
oe->op = NULL;
oe->rank = (e->flags & EDGE_TRUE_VALUE)
? BIT_IOR_EXPR : BIT_AND_EXPR;
/* oe->op = NULL signs that there is no SSA_NAME
for the range test, and oe->id instead is the
basic block number, at which's end the GIMPLE_COND
is. */
oe->id = bb->index;
oe->count = 1;
ops.safe_push (oe);
}
if (bb == first_bb)
break;
}
if (ops.length () > 1)
optimize_range_tests (ERROR_MARK, &ops);
ops.release ();
}
/* Return true if OPERAND is defined by a PHI node which uses the LHS
of STMT in it's operands. This is also known as a "destructive
update" operation. */
static bool
is_phi_for_stmt (gimple stmt, tree operand)
{
gimple def_stmt;
tree lhs;
use_operand_p arg_p;
ssa_op_iter i;
if (TREE_CODE (operand) != SSA_NAME)
return false;
lhs = gimple_assign_lhs (stmt);
def_stmt = SSA_NAME_DEF_STMT (operand);
if (gimple_code (def_stmt) != GIMPLE_PHI)
return false;
FOR_EACH_PHI_ARG (arg_p, def_stmt, i, SSA_OP_USE)
if (lhs == USE_FROM_PTR (arg_p))
return true;
return false;
}
/* Remove def stmt of VAR if VAR has zero uses and recurse
on rhs1 operand if so. */
static void
remove_visited_stmt_chain (tree var)
{
gimple stmt;
gimple_stmt_iterator gsi;
while (1)
{
if (TREE_CODE (var) != SSA_NAME || !has_zero_uses (var))
return;
stmt = SSA_NAME_DEF_STMT (var);
if (is_gimple_assign (stmt) && gimple_visited_p (stmt))
{
var = gimple_assign_rhs1 (stmt);
gsi = gsi_for_stmt (stmt);
gsi_remove (&gsi, true);
release_defs (stmt);
}
else
return;
}
}
/* This function checks three consequtive operands in
passed operands vector OPS starting from OPINDEX and
swaps two operands if it is profitable for binary operation
consuming OPINDEX + 1 abnd OPINDEX + 2 operands.
We pair ops with the same rank if possible.
The alternative we try is to see if STMT is a destructive
update style statement, which is like:
b = phi (a, ...)
a = c + b;
In that case, we want to use the destructive update form to
expose the possible vectorizer sum reduction opportunity.
In that case, the third operand will be the phi node. This
check is not performed if STMT is null.
We could, of course, try to be better as noted above, and do a
lot of work to try to find these opportunities in >3 operand
cases, but it is unlikely to be worth it. */
static void
swap_ops_for_binary_stmt (vec<operand_entry_t> ops,
unsigned int opindex, gimple stmt)
{
operand_entry_t oe1, oe2, oe3;
oe1 = ops[opindex];
oe2 = ops[opindex + 1];
oe3 = ops[opindex + 2];
if ((oe1->rank == oe2->rank
&& oe2->rank != oe3->rank)
|| (stmt && is_phi_for_stmt (stmt, oe3->op)
&& !is_phi_for_stmt (stmt, oe1->op)
&& !is_phi_for_stmt (stmt, oe2->op)))
{
struct operand_entry temp = *oe3;
oe3->op = oe1->op;
oe3->rank = oe1->rank;
oe1->op = temp.op;
oe1->rank= temp.rank;
}
else if ((oe1->rank == oe3->rank
&& oe2->rank != oe3->rank)
|| (stmt && is_phi_for_stmt (stmt, oe2->op)
&& !is_phi_for_stmt (stmt, oe1->op)
&& !is_phi_for_stmt (stmt, oe3->op)))
{
struct operand_entry temp = *oe2;
oe2->op = oe1->op;
oe2->rank = oe1->rank;
oe1->op = temp.op;
oe1->rank= temp.rank;
}
}
/* Recursively rewrite our linearized statements so that the operators
match those in OPS[OPINDEX], putting the computation in rank
order. */
static void
rewrite_expr_tree (gimple stmt, unsigned int opindex,
vec<operand_entry_t> ops, bool moved)
{
tree rhs1 = gimple_assign_rhs1 (stmt);
tree rhs2 = gimple_assign_rhs2 (stmt);
operand_entry_t oe;
/* If we have three operands left, then we want to make sure the ones
that get the double binary op are chosen wisely. */
if (opindex + 3 == ops.length ())
swap_ops_for_binary_stmt (ops, opindex, stmt);
/* The final recursion case for this function is that you have
exactly two operations left.
If we had one exactly one op in the entire list to start with, we
would have never called this function, and the tail recursion
rewrites them one at a time. */
if (opindex + 2 == ops.length ())
{
operand_entry_t oe1, oe2;
oe1 = ops[opindex];
oe2 = ops[opindex + 1];
if (rhs1 != oe1->op || rhs2 != oe2->op)
{
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "Transforming ");
print_gimple_stmt (dump_file, stmt, 0, 0);
}
gimple_assign_set_rhs1 (stmt, oe1->op);
gimple_assign_set_rhs2 (stmt, oe2->op);
update_stmt (stmt);
if (rhs1 != oe1->op && rhs1 != oe2->op)
remove_visited_stmt_chain (rhs1);
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, " into ");
print_gimple_stmt (dump_file, stmt, 0, 0);
}
}
return;
}
/* If we hit here, we should have 3 or more ops left. */
gcc_assert (opindex + 2 < ops.length ());
/* Rewrite the next operator. */
oe = ops[opindex];
if (oe->op != rhs2)
{
if (!moved)
{
gimple_stmt_iterator gsinow, gsirhs1;
gimple stmt1 = stmt, stmt2;
unsigned int count;
gsinow = gsi_for_stmt (stmt);
count = ops.length () - opindex - 2;
while (count-- != 0)
{
stmt2 = SSA_NAME_DEF_STMT (gimple_assign_rhs1 (stmt1));
gsirhs1 = gsi_for_stmt (stmt2);
gsi_move_before (&gsirhs1, &gsinow);
gsi_prev (&gsinow);
stmt1 = stmt2;
}
moved = true;
}
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "Transforming ");
print_gimple_stmt (dump_file, stmt, 0, 0);
}
gimple_assign_set_rhs2 (stmt, oe->op);
update_stmt (stmt);
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, " into ");
print_gimple_stmt (dump_file, stmt, 0, 0);
}
}
/* Recurse on the LHS of the binary operator, which is guaranteed to
be the non-leaf side. */
rewrite_expr_tree (SSA_NAME_DEF_STMT (rhs1), opindex + 1, ops, moved);
}
/* Find out how many cycles we need to compute statements chain.
OPS_NUM holds number os statements in a chain. CPU_WIDTH is a
maximum number of independent statements we may execute per cycle. */
static int
get_required_cycles (int ops_num, int cpu_width)
{
int res;
int elog;
unsigned int rest;
/* While we have more than 2 * cpu_width operands
we may reduce number of operands by cpu_width
per cycle. */
res = ops_num / (2 * cpu_width);
/* Remained operands count may be reduced twice per cycle
until we have only one operand. */
rest = (unsigned)(ops_num - res * cpu_width);
elog = exact_log2 (rest);
if (elog >= 0)
res += elog;
else
res += floor_log2 (rest) + 1;
return res;
}
/* Returns an optimal number of registers to use for computation of
given statements. */
static int
get_reassociation_width (int ops_num, enum tree_code opc,
enum machine_mode mode)
{
int param_width = PARAM_VALUE (PARAM_TREE_REASSOC_WIDTH);
int width;
int width_min;
int cycles_best;
if (param_width > 0)
width = param_width;
else
width = targetm.sched.reassociation_width (opc, mode);
if (width == 1)
return width;
/* Get the minimal time required for sequence computation. */
cycles_best = get_required_cycles (ops_num, width);
/* Check if we may use less width and still compute sequence for
the same time. It will allow us to reduce registers usage.
get_required_cycles is monotonically increasing with lower width
so we can perform a binary search for the minimal width that still
results in the optimal cycle count. */
width_min = 1;
while (width > width_min)
{
int width_mid = (width + width_min) / 2;
if (get_required_cycles (ops_num, width_mid) == cycles_best)
width = width_mid;
else if (width_min < width_mid)
width_min = width_mid;
else
break;
}
return width;
}
/* Recursively rewrite our linearized statements so that the operators
match those in OPS[OPINDEX], putting the computation in rank
order and trying to allow operations to be executed in
parallel. */
static void
rewrite_expr_tree_parallel (gimple stmt, int width,
vec<operand_entry_t> ops)
{
enum tree_code opcode = gimple_assign_rhs_code (stmt);
int op_num = ops.length ();
int stmt_num = op_num - 1;
gimple *stmts = XALLOCAVEC (gimple, stmt_num);
int op_index = op_num - 1;
int stmt_index = 0;
int ready_stmts_end = 0;
int i = 0;
tree last_rhs1 = gimple_assign_rhs1 (stmt);
/* We start expression rewriting from the top statements.
So, in this loop we create a full list of statements
we will work with. */
stmts[stmt_num - 1] = stmt;
for (i = stmt_num - 2; i >= 0; i--)
stmts[i] = SSA_NAME_DEF_STMT (gimple_assign_rhs1 (stmts[i+1]));
for (i = 0; i < stmt_num; i++)
{
tree op1, op2;
/* Determine whether we should use results of
already handled statements or not. */
if (ready_stmts_end == 0
&& (i - stmt_index >= width || op_index < 1))
ready_stmts_end = i;
/* Now we choose operands for the next statement. Non zero
value in ready_stmts_end means here that we should use
the result of already generated statements as new operand. */
if (ready_stmts_end > 0)
{
op1 = gimple_assign_lhs (stmts[stmt_index++]);
if (ready_stmts_end > stmt_index)
op2 = gimple_assign_lhs (stmts[stmt_index++]);
else if (op_index >= 0)
op2 = ops[op_index--]->op;
else
{
gcc_assert (stmt_index < i);
op2 = gimple_assign_lhs (stmts[stmt_index++]);
}
if (stmt_index >= ready_stmts_end)
ready_stmts_end = 0;
}
else
{
if (op_index > 1)
swap_ops_for_binary_stmt (ops, op_index - 2, NULL);
op2 = ops[op_index--]->op;
op1 = ops[op_index--]->op;
}
/* If we emit the last statement then we should put
operands into the last statement. It will also
break the loop. */
if (op_index < 0 && stmt_index == i)
i = stmt_num - 1;
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "Transforming ");
print_gimple_stmt (dump_file, stmts[i], 0, 0);
}
/* We keep original statement only for the last one. All
others are recreated. */
if (i == stmt_num - 1)
{
gimple_assign_set_rhs1 (stmts[i], op1);
gimple_assign_set_rhs2 (stmts[i], op2);
update_stmt (stmts[i]);
}
else
stmts[i] = build_and_add_sum (TREE_TYPE (last_rhs1), op1, op2, opcode);
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, " into ");
print_gimple_stmt (dump_file, stmts[i], 0, 0);
}
}
remove_visited_stmt_chain (last_rhs1);
}
/* Transform STMT, which is really (A +B) + (C + D) into the left
linear form, ((A+B)+C)+D.
Recurse on D if necessary. */
static void
linearize_expr (gimple stmt)
{
gimple_stmt_iterator gsinow, gsirhs;
gimple binlhs = SSA_NAME_DEF_STMT (gimple_assign_rhs1 (stmt));
gimple binrhs = SSA_NAME_DEF_STMT (gimple_assign_rhs2 (stmt));
enum tree_code rhscode = gimple_assign_rhs_code (stmt);
gimple newbinrhs = NULL;
struct loop *loop = loop_containing_stmt (stmt);
gcc_assert (is_reassociable_op (binlhs, rhscode, loop)
&& is_reassociable_op (binrhs, rhscode, loop));
gsinow = gsi_for_stmt (stmt);
gsirhs = gsi_for_stmt (binrhs);
gsi_move_before (&gsirhs, &gsinow);
gimple_assign_set_rhs2 (stmt, gimple_assign_rhs1 (binrhs));
gimple_assign_set_rhs1 (binrhs, gimple_assign_lhs (binlhs));
gimple_assign_set_rhs1 (stmt, gimple_assign_lhs (binrhs));
if (TREE_CODE (gimple_assign_rhs2 (stmt)) == SSA_NAME)
newbinrhs = SSA_NAME_DEF_STMT (gimple_assign_rhs2 (stmt));
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "Linearized: ");
print_gimple_stmt (dump_file, stmt, 0, 0);
}
reassociate_stats.linearized++;
update_stmt (binrhs);
update_stmt (binlhs);
update_stmt (stmt);
gimple_set_visited (stmt, true);
gimple_set_visited (binlhs, true);
gimple_set_visited (binrhs, true);
/* Tail recurse on the new rhs if it still needs reassociation. */
if (newbinrhs && is_reassociable_op (newbinrhs, rhscode, loop))
/* ??? This should probably be linearize_expr (newbinrhs) but I don't
want to change the algorithm while converting to tuples. */
linearize_expr (stmt);
}
/* If LHS has a single immediate use that is a GIMPLE_ASSIGN statement, return
it. Otherwise, return NULL. */
static gimple
get_single_immediate_use (tree lhs)
{
use_operand_p immuse;