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| Current File : //usr/src/contrib/gcc/tree-vect-generic.c |
/* Lower vector operations to scalar operations.
Copyright (C) 2004, 2005, 2006, 2007 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
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 COPYING. If not, write to the Free
Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301, USA. */
#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tree.h"
#include "tm.h"
#include "rtl.h"
#include "expr.h"
#include "insn-codes.h"
#include "diagnostic.h"
#include "optabs.h"
#include "machmode.h"
#include "langhooks.h"
#include "tree-flow.h"
#include "tree-gimple.h"
#include "tree-iterator.h"
#include "tree-pass.h"
#include "flags.h"
#include "ggc.h"
/* Build a constant of type TYPE, made of VALUE's bits replicated
every TYPE_SIZE (INNER_TYPE) bits to fit TYPE's precision. */
static tree
build_replicated_const (tree type, tree inner_type, HOST_WIDE_INT value)
{
int width = tree_low_cst (TYPE_SIZE (inner_type), 1);
int n = HOST_BITS_PER_WIDE_INT / width;
unsigned HOST_WIDE_INT low, high, mask;
tree ret;
gcc_assert (n);
if (width == HOST_BITS_PER_WIDE_INT)
low = value;
else
{
mask = ((HOST_WIDE_INT)1 << width) - 1;
low = (unsigned HOST_WIDE_INT) ~0 / mask * (value & mask);
}
if (TYPE_PRECISION (type) < HOST_BITS_PER_WIDE_INT)
low &= ((HOST_WIDE_INT)1 << TYPE_PRECISION (type)) - 1, high = 0;
else if (TYPE_PRECISION (type) == HOST_BITS_PER_WIDE_INT)
high = 0;
else if (TYPE_PRECISION (type) == 2 * HOST_BITS_PER_WIDE_INT)
high = low;
else
gcc_unreachable ();
ret = build_int_cst_wide (type, low, high);
return ret;
}
static GTY(()) tree vector_inner_type;
static GTY(()) tree vector_last_type;
static GTY(()) int vector_last_nunits;
/* Return a suitable vector types made of SUBPARTS units each of mode
"word_mode" (the global variable). */
static tree
build_word_mode_vector_type (int nunits)
{
if (!vector_inner_type)
vector_inner_type = lang_hooks.types.type_for_mode (word_mode, 1);
else if (vector_last_nunits == nunits)
{
gcc_assert (TREE_CODE (vector_last_type) == VECTOR_TYPE);
return vector_last_type;
}
/* We build a new type, but we canonicalize it nevertheless,
because it still saves some memory. */
vector_last_nunits = nunits;
vector_last_type = type_hash_canon (nunits,
build_vector_type (vector_inner_type,
nunits));
return vector_last_type;
}
typedef tree (*elem_op_func) (block_stmt_iterator *,
tree, tree, tree, tree, tree, enum tree_code);
static inline tree
tree_vec_extract (block_stmt_iterator *bsi, tree type,
tree t, tree bitsize, tree bitpos)
{
if (bitpos)
return gimplify_build3 (bsi, BIT_FIELD_REF, type, t, bitsize, bitpos);
else
return gimplify_build1 (bsi, VIEW_CONVERT_EXPR, type, t);
}
static tree
do_unop (block_stmt_iterator *bsi, tree inner_type, tree a,
tree b ATTRIBUTE_UNUSED, tree bitpos, tree bitsize,
enum tree_code code)
{
a = tree_vec_extract (bsi, inner_type, a, bitsize, bitpos);
return gimplify_build1 (bsi, code, inner_type, a);
}
static tree
do_binop (block_stmt_iterator *bsi, tree inner_type, tree a, tree b,
tree bitpos, tree bitsize, enum tree_code code)
{
a = tree_vec_extract (bsi, inner_type, a, bitsize, bitpos);
b = tree_vec_extract (bsi, inner_type, b, bitsize, bitpos);
return gimplify_build2 (bsi, code, inner_type, a, b);
}
/* Expand vector addition to scalars. This does bit twiddling
in order to increase parallelism:
a + b = (((int) a & 0x7f7f7f7f) + ((int) b & 0x7f7f7f7f)) ^
(a ^ b) & 0x80808080
a - b = (((int) a | 0x80808080) - ((int) b & 0x7f7f7f7f)) ^
(a ^ ~b) & 0x80808080
-b = (0x80808080 - ((int) b & 0x7f7f7f7f)) ^ (~b & 0x80808080)
This optimization should be done only if 4 vector items or more
fit into a word. */
static tree
do_plus_minus (block_stmt_iterator *bsi, tree word_type, tree a, tree b,
tree bitpos ATTRIBUTE_UNUSED, tree bitsize ATTRIBUTE_UNUSED,
enum tree_code code)
{
tree inner_type = TREE_TYPE (TREE_TYPE (a));
unsigned HOST_WIDE_INT max;
tree low_bits, high_bits, a_low, b_low, result_low, signs;
max = GET_MODE_MASK (TYPE_MODE (inner_type));
low_bits = build_replicated_const (word_type, inner_type, max >> 1);
high_bits = build_replicated_const (word_type, inner_type, max & ~(max >> 1));
a = tree_vec_extract (bsi, word_type, a, bitsize, bitpos);
b = tree_vec_extract (bsi, word_type, b, bitsize, bitpos);
signs = gimplify_build2 (bsi, BIT_XOR_EXPR, word_type, a, b);
b_low = gimplify_build2 (bsi, BIT_AND_EXPR, word_type, b, low_bits);
if (code == PLUS_EXPR)
a_low = gimplify_build2 (bsi, BIT_AND_EXPR, word_type, a, low_bits);
else
{
a_low = gimplify_build2 (bsi, BIT_IOR_EXPR, word_type, a, high_bits);
signs = gimplify_build1 (bsi, BIT_NOT_EXPR, word_type, signs);
}
signs = gimplify_build2 (bsi, BIT_AND_EXPR, word_type, signs, high_bits);
result_low = gimplify_build2 (bsi, code, word_type, a_low, b_low);
return gimplify_build2 (bsi, BIT_XOR_EXPR, word_type, result_low, signs);
}
static tree
do_negate (block_stmt_iterator *bsi, tree word_type, tree b,
tree unused ATTRIBUTE_UNUSED, tree bitpos ATTRIBUTE_UNUSED,
tree bitsize ATTRIBUTE_UNUSED,
enum tree_code code ATTRIBUTE_UNUSED)
{
tree inner_type = TREE_TYPE (TREE_TYPE (b));
HOST_WIDE_INT max;
tree low_bits, high_bits, b_low, result_low, signs;
max = GET_MODE_MASK (TYPE_MODE (inner_type));
low_bits = build_replicated_const (word_type, inner_type, max >> 1);
high_bits = build_replicated_const (word_type, inner_type, max & ~(max >> 1));
b = tree_vec_extract (bsi, word_type, b, bitsize, bitpos);
b_low = gimplify_build2 (bsi, BIT_AND_EXPR, word_type, b, low_bits);
signs = gimplify_build1 (bsi, BIT_NOT_EXPR, word_type, b);
signs = gimplify_build2 (bsi, BIT_AND_EXPR, word_type, signs, high_bits);
result_low = gimplify_build2 (bsi, MINUS_EXPR, word_type, high_bits, b_low);
return gimplify_build2 (bsi, BIT_XOR_EXPR, word_type, result_low, signs);
}
/* Expand a vector operation to scalars, by using many operations
whose type is the vector type's inner type. */
static tree
expand_vector_piecewise (block_stmt_iterator *bsi, elem_op_func f,
tree type, tree inner_type,
tree a, tree b, enum tree_code code)
{
VEC(constructor_elt,gc) *v;
tree part_width = TYPE_SIZE (inner_type);
tree index = bitsize_int (0);
int nunits = TYPE_VECTOR_SUBPARTS (type);
int delta = tree_low_cst (part_width, 1)
/ tree_low_cst (TYPE_SIZE (TREE_TYPE (type)), 1);
int i;
v = VEC_alloc(constructor_elt, gc, (nunits + delta - 1) / delta);
for (i = 0; i < nunits;
i += delta, index = int_const_binop (PLUS_EXPR, index, part_width, 0))
{
tree result = f (bsi, inner_type, a, b, index, part_width, code);
constructor_elt *ce = VEC_quick_push (constructor_elt, v, NULL);
ce->index = NULL_TREE;
ce->value = result;
}
return build_constructor (type, v);
}
/* Expand a vector operation to scalars with the freedom to use
a scalar integer type, or to use a different size for the items
in the vector type. */
static tree
expand_vector_parallel (block_stmt_iterator *bsi, elem_op_func f, tree type,
tree a, tree b,
enum tree_code code)
{
tree result, compute_type;
enum machine_mode mode;
int n_words = tree_low_cst (TYPE_SIZE_UNIT (type), 1) / UNITS_PER_WORD;
/* We have three strategies. If the type is already correct, just do
the operation an element at a time. Else, if the vector is wider than
one word, do it a word at a time; finally, if the vector is smaller
than one word, do it as a scalar. */
if (TYPE_MODE (TREE_TYPE (type)) == word_mode)
return expand_vector_piecewise (bsi, f,
type, TREE_TYPE (type),
a, b, code);
else if (n_words > 1)
{
tree word_type = build_word_mode_vector_type (n_words);
result = expand_vector_piecewise (bsi, f,
word_type, TREE_TYPE (word_type),
a, b, code);
result = gimplify_val (bsi, word_type, result);
}
else
{
/* Use a single scalar operation with a mode no wider than word_mode. */
mode = mode_for_size (tree_low_cst (TYPE_SIZE (type), 1), MODE_INT, 0);
compute_type = lang_hooks.types.type_for_mode (mode, 1);
result = f (bsi, compute_type, a, b, NULL_TREE, NULL_TREE, code);
}
return result;
}
/* Expand a vector operation to scalars; for integer types we can use
special bit twiddling tricks to do the sums a word at a time, using
function F_PARALLEL instead of F. These tricks are done only if
they can process at least four items, that is, only if the vector
holds at least four items and if a word can hold four items. */
static tree
expand_vector_addition (block_stmt_iterator *bsi,
elem_op_func f, elem_op_func f_parallel,
tree type, tree a, tree b, enum tree_code code)
{
int parts_per_word = UNITS_PER_WORD
/ tree_low_cst (TYPE_SIZE_UNIT (TREE_TYPE (type)), 1);
if (INTEGRAL_TYPE_P (TREE_TYPE (type))
&& parts_per_word >= 4
&& TYPE_VECTOR_SUBPARTS (type) >= 4)
return expand_vector_parallel (bsi, f_parallel,
type, a, b, code);
else
return expand_vector_piecewise (bsi, f,
type, TREE_TYPE (type),
a, b, code);
}
static tree
expand_vector_operation (block_stmt_iterator *bsi, tree type, tree compute_type,
tree rhs, enum tree_code code)
{
enum machine_mode compute_mode = TYPE_MODE (compute_type);
/* If the compute mode is not a vector mode (hence we are not decomposing
a BLKmode vector to smaller, hardware-supported vectors), we may want
to expand the operations in parallel. */
if (GET_MODE_CLASS (compute_mode) != MODE_VECTOR_INT
&& GET_MODE_CLASS (compute_mode) != MODE_VECTOR_FLOAT)
switch (code)
{
case PLUS_EXPR:
case MINUS_EXPR:
if (!TYPE_OVERFLOW_TRAPS (type))
return expand_vector_addition (bsi, do_binop, do_plus_minus, type,
TREE_OPERAND (rhs, 0),
TREE_OPERAND (rhs, 1), code);
break;
case NEGATE_EXPR:
if (!TYPE_OVERFLOW_TRAPS (type))
return expand_vector_addition (bsi, do_unop, do_negate, type,
TREE_OPERAND (rhs, 0),
NULL_TREE, code);
break;
case BIT_AND_EXPR:
case BIT_IOR_EXPR:
case BIT_XOR_EXPR:
return expand_vector_parallel (bsi, do_binop, type,
TREE_OPERAND (rhs, 0),
TREE_OPERAND (rhs, 1), code);
case BIT_NOT_EXPR:
return expand_vector_parallel (bsi, do_unop, type,
TREE_OPERAND (rhs, 0),
NULL_TREE, code);
default:
break;
}
if (TREE_CODE_CLASS (code) == tcc_unary)
return expand_vector_piecewise (bsi, do_unop, type, compute_type,
TREE_OPERAND (rhs, 0),
NULL_TREE, code);
else
return expand_vector_piecewise (bsi, do_binop, type, compute_type,
TREE_OPERAND (rhs, 0),
TREE_OPERAND (rhs, 1), code);
}
/* Return a type for the widest vector mode whose components are of mode
INNER_MODE, or NULL_TREE if none is found. */
static tree
type_for_widest_vector_mode (enum machine_mode inner_mode, optab op)
{
enum machine_mode best_mode = VOIDmode, mode;
int best_nunits = 0;
if (SCALAR_FLOAT_MODE_P (inner_mode))
mode = MIN_MODE_VECTOR_FLOAT;
else
mode = MIN_MODE_VECTOR_INT;
for (; mode != VOIDmode; mode = GET_MODE_WIDER_MODE (mode))
if (GET_MODE_INNER (mode) == inner_mode
&& GET_MODE_NUNITS (mode) > best_nunits
&& op->handlers[mode].insn_code != CODE_FOR_nothing)
best_mode = mode, best_nunits = GET_MODE_NUNITS (mode);
if (best_mode == VOIDmode)
return NULL_TREE;
else
return lang_hooks.types.type_for_mode (best_mode, 1);
}
/* Process one statement. If we identify a vector operation, expand it. */
static void
expand_vector_operations_1 (block_stmt_iterator *bsi)
{
tree stmt = bsi_stmt (*bsi);
tree *p_lhs, *p_rhs, lhs, rhs, type, compute_type;
enum tree_code code;
enum machine_mode compute_mode;
optab op;
switch (TREE_CODE (stmt))
{
case RETURN_EXPR:
stmt = TREE_OPERAND (stmt, 0);
if (!stmt || TREE_CODE (stmt) != MODIFY_EXPR)
return;
/* FALLTHRU */
case MODIFY_EXPR:
p_lhs = &TREE_OPERAND (stmt, 0);
p_rhs = &TREE_OPERAND (stmt, 1);
lhs = *p_lhs;
rhs = *p_rhs;
break;
default:
return;
}
type = TREE_TYPE (rhs);
if (TREE_CODE (type) != VECTOR_TYPE)
return;
code = TREE_CODE (rhs);
if (TREE_CODE_CLASS (code) != tcc_unary
&& TREE_CODE_CLASS (code) != tcc_binary)
return;
if (code == NOP_EXPR || code == VIEW_CONVERT_EXPR)
return;
gcc_assert (code != CONVERT_EXPR);
op = optab_for_tree_code (code, type);
/* For widening vector operations, the relevant type is of the arguments,
not the widened result. */
if (code == WIDEN_SUM_EXPR)
type = TREE_TYPE (TREE_OPERAND (rhs, 0));
/* Optabs will try converting a negation into a subtraction, so
look for it as well. TODO: negation of floating-point vectors
might be turned into an exclusive OR toggling the sign bit. */
if (op == NULL
&& code == NEGATE_EXPR
&& INTEGRAL_TYPE_P (TREE_TYPE (type)))
op = optab_for_tree_code (MINUS_EXPR, type);
/* For very wide vectors, try using a smaller vector mode. */
compute_type = type;
if (TYPE_MODE (type) == BLKmode && op)
{
tree vector_compute_type
= type_for_widest_vector_mode (TYPE_MODE (TREE_TYPE (type)), op);
if (vector_compute_type != NULL_TREE)
compute_type = vector_compute_type;
}
/* If we are breaking a BLKmode vector into smaller pieces,
type_for_widest_vector_mode has already looked into the optab,
so skip these checks. */
if (compute_type == type)
{
compute_mode = TYPE_MODE (compute_type);
if ((GET_MODE_CLASS (compute_mode) == MODE_VECTOR_INT
|| GET_MODE_CLASS (compute_mode) == MODE_VECTOR_FLOAT)
&& op != NULL
&& op->handlers[compute_mode].insn_code != CODE_FOR_nothing)
return;
else
/* There is no operation in hardware, so fall back to scalars. */
compute_type = TREE_TYPE (type);
}
gcc_assert (code != VEC_LSHIFT_EXPR && code != VEC_RSHIFT_EXPR);
rhs = expand_vector_operation (bsi, type, compute_type, rhs, code);
if (lang_hooks.types_compatible_p (TREE_TYPE (lhs), TREE_TYPE (rhs)))
*p_rhs = rhs;
else
*p_rhs = gimplify_build1 (bsi, VIEW_CONVERT_EXPR, TREE_TYPE (lhs), rhs);
mark_stmt_modified (bsi_stmt (*bsi));
}
/* Use this to lower vector operations introduced by the vectorizer,
if it may need the bit-twiddling tricks implemented in this file. */
static bool
gate_expand_vector_operations (void)
{
return flag_tree_vectorize != 0;
}
static unsigned int
expand_vector_operations (void)
{
block_stmt_iterator bsi;
basic_block bb;
FOR_EACH_BB (bb)
{
for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
{
expand_vector_operations_1 (&bsi);
update_stmt_if_modified (bsi_stmt (bsi));
}
}
return 0;
}
struct tree_opt_pass pass_lower_vector =
{
"veclower", /* name */
0, /* gate */
expand_vector_operations, /* execute */
NULL, /* sub */
NULL, /* next */
0, /* static_pass_number */
0, /* tv_id */
PROP_cfg, /* properties_required */
0, /* properties_provided */
0, /* properties_destroyed */
0, /* todo_flags_start */
TODO_dump_func | TODO_ggc_collect
| TODO_verify_stmts, /* todo_flags_finish */
0 /* letter */
};
struct tree_opt_pass pass_lower_vector_ssa =
{
"veclower2", /* name */
gate_expand_vector_operations, /* gate */
expand_vector_operations, /* execute */
NULL, /* sub */
NULL, /* next */
0, /* static_pass_number */
0, /* tv_id */
PROP_cfg, /* properties_required */
0, /* properties_provided */
0, /* properties_destroyed */
0, /* todo_flags_start */
TODO_dump_func | TODO_update_ssa /* todo_flags_finish */
| TODO_verify_ssa
| TODO_verify_stmts | TODO_verify_flow,
0 /* letter */
};
#include "gt-tree-vect-generic.h"