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/* A representation of vector permutation indices.
Copyright (C) 2017-2019 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 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 "vec-perm-indices.h"
#include "tree.h"
#include "fold-const.h"
#include "tree-vector-builder.h"
#include "backend.h"
#include "rtl.h"
#include "memmodel.h"
#include "emit-rtl.h"
#include "selftest.h"
#include "rtx-vector-builder.h"
/* Switch to a new permutation vector that selects between NINPUTS vector
inputs that have NELTS_PER_INPUT elements each. Take the elements of the
new permutation vector from ELEMENTS, clamping each one to be in range. */
void
vec_perm_indices::new_vector (const vec_perm_builder &elements,
unsigned int ninputs,
poly_uint64 nelts_per_input)
{
m_ninputs = ninputs;
m_nelts_per_input = nelts_per_input;
/* If the vector has a constant number of elements, expand the
encoding and clamp each element. E.g. { 0, 2, 4, ... } might
wrap halfway if there is only one vector input, and we want
the wrapped form to be the canonical one.
If the vector has a variable number of elements, just copy
the encoding. In that case the unwrapped form is canonical
and there is no way of representing the wrapped form. */
poly_uint64 full_nelts = elements.full_nelts ();
unsigned HOST_WIDE_INT copy_nelts;
if (full_nelts.is_constant (&copy_nelts))
m_encoding.new_vector (full_nelts, copy_nelts, 1);
else
{
copy_nelts = elements.encoded_nelts ();
m_encoding.new_vector (full_nelts, elements.npatterns (),
elements.nelts_per_pattern ());
}
unsigned int npatterns = m_encoding.npatterns ();
for (unsigned int i = 0; i < npatterns; ++i)
m_encoding.quick_push (clamp (elements.elt (i)));
/* Use the fact that:
(a + b) % c == ((a % c) + (b % c)) % c
to simplify the clamping of variable-length vectors. */
for (unsigned int i = npatterns; i < copy_nelts; ++i)
{
element_type step = clamp (elements.elt (i)
- elements.elt (i - npatterns));
m_encoding.quick_push (clamp (m_encoding[i - npatterns] + step));
}
m_encoding.finalize ();
}
/* Switch to a new permutation vector that selects the same input elements
as ORIG, but with each element split into FACTOR pieces. For example,
if ORIG is { 1, 2, 0, 3 } and FACTOR is 2, the new permutation is
{ 2, 3, 4, 5, 0, 1, 6, 7 }. */
void
vec_perm_indices::new_expanded_vector (const vec_perm_indices &orig,
unsigned int factor)
{
m_ninputs = orig.m_ninputs;
m_nelts_per_input = orig.m_nelts_per_input * factor;
m_encoding.new_vector (orig.m_encoding.full_nelts () * factor,
orig.m_encoding.npatterns () * factor,
orig.m_encoding.nelts_per_pattern ());
unsigned int encoded_nelts = orig.m_encoding.encoded_nelts ();
for (unsigned int i = 0; i < encoded_nelts; ++i)
{
element_type base = orig.m_encoding[i] * factor;
for (unsigned int j = 0; j < factor; ++j)
m_encoding.quick_push (base + j);
}
m_encoding.finalize ();
}
/* Rotate the inputs of the permutation right by DELTA inputs. This changes
the values of the permutation vector but it doesn't change the way that
the elements are encoded. */
void
vec_perm_indices::rotate_inputs (int delta)
{
element_type element_delta = delta * m_nelts_per_input;
for (unsigned int i = 0; i < m_encoding.length (); ++i)
m_encoding[i] = clamp (m_encoding[i] + element_delta);
}
/* Return true if index OUT_BASE + I * OUT_STEP selects input
element IN_BASE + I * IN_STEP. For example, the call to test
whether a permute reverses a vector of N elements would be:
series_p (0, 1, N - 1, -1)
which would return true for { N - 1, N - 2, N - 3, ... }.
The calls to test for an interleaving of elements starting
at N1 and N2 would be:
series_p (0, 2, N1, 1) && series_p (1, 2, N2, 1).
which would return true for { N1, N2, N1 + 1, N2 + 1, ... }. */
bool
vec_perm_indices::series_p (unsigned int out_base, unsigned int out_step,
element_type in_base, element_type in_step) const
{
/* Check the base value. */
if (maybe_ne (clamp (m_encoding.elt (out_base)), clamp (in_base)))
return false;
element_type full_nelts = m_encoding.full_nelts ();
unsigned int npatterns = m_encoding.npatterns ();
/* Calculate which multiple of OUT_STEP elements we need to get
back to the same pattern. */
unsigned int cycle_length = least_common_multiple (out_step, npatterns);
/* Check the steps. */
in_step = clamp (in_step);
out_base += out_step;
unsigned int limit = 0;
for (;;)
{
/* Succeed if we've checked all the elements in the vector. */
if (known_ge (out_base, full_nelts))
return true;
if (out_base >= npatterns)
{
/* We've got to the end of the "foreground" values. Check
2 elements from each pattern in the "background" values. */
if (limit == 0)
limit = out_base + cycle_length * 2;
else if (out_base >= limit)
return true;
}
element_type v0 = m_encoding.elt (out_base - out_step);
element_type v1 = m_encoding.elt (out_base);
if (maybe_ne (clamp (v1 - v0), in_step))
return false;
out_base += out_step;
}
return true;
}
/* Return true if all elements of the permutation vector are in the range
[START, START + SIZE). */
bool
vec_perm_indices::all_in_range_p (element_type start, element_type size) const
{
/* Check the first two elements of each pattern. */
unsigned int npatterns = m_encoding.npatterns ();
unsigned int nelts_per_pattern = m_encoding.nelts_per_pattern ();
unsigned int base_nelts = npatterns * MIN (nelts_per_pattern, 2);
for (unsigned int i = 0; i < base_nelts; ++i)
if (!known_in_range_p (m_encoding[i], start, size))
return false;
/* For stepped encodings, check the full range of the series. */
if (nelts_per_pattern == 3)
{
element_type limit = input_nelts ();
/* The number of elements in each pattern beyond the first two
that we checked above. */
poly_int64 step_nelts = exact_div (m_encoding.full_nelts (),
npatterns) - 2;
for (unsigned int i = 0; i < npatterns; ++i)
{
/* BASE1 has been checked but BASE2 hasn't. */
element_type base1 = m_encoding[i + npatterns];
element_type base2 = m_encoding[i + base_nelts];
/* The step to add to get from BASE1 to each subsequent value. */
element_type step = clamp (base2 - base1);
/* STEP has no inherent sign, so a value near LIMIT can
act as a negative step. The series is in range if it
is in range according to one of the two interpretations.
Since we're dealing with clamped values, ELEMENT_TYPE is
wide enough for overflow not to be a problem. */
element_type headroom_down = base1 - start;
element_type headroom_up = size - headroom_down - 1;
HOST_WIDE_INT diff;
if ((!step.is_constant (&diff)
|| maybe_lt (headroom_up, diff * step_nelts))
&& (!(limit - step).is_constant (&diff)
|| maybe_lt (headroom_down, diff * step_nelts)))
return false;
}
}
return true;
}
/* Try to read the contents of VECTOR_CST CST as a constant permutation
vector. Return true and add the elements to BUILDER on success,
otherwise return false without modifying BUILDER. */
bool
tree_to_vec_perm_builder (vec_perm_builder *builder, tree cst)
{
unsigned int encoded_nelts = vector_cst_encoded_nelts (cst);
for (unsigned int i = 0; i < encoded_nelts; ++i)
if (!tree_fits_poly_int64_p (VECTOR_CST_ENCODED_ELT (cst, i)))
return false;
builder->new_vector (TYPE_VECTOR_SUBPARTS (TREE_TYPE (cst)),
VECTOR_CST_NPATTERNS (cst),
VECTOR_CST_NELTS_PER_PATTERN (cst));
for (unsigned int i = 0; i < encoded_nelts; ++i)
builder->quick_push (tree_to_poly_int64 (VECTOR_CST_ENCODED_ELT (cst, i)));
return true;
}
/* Return a VECTOR_CST of type TYPE for the permutation vector in INDICES. */
tree
vec_perm_indices_to_tree (tree type, const vec_perm_indices &indices)
{
gcc_assert (known_eq (TYPE_VECTOR_SUBPARTS (type), indices.length ()));
tree_vector_builder sel (type, indices.encoding ().npatterns (),
indices.encoding ().nelts_per_pattern ());
unsigned int encoded_nelts = sel.encoded_nelts ();
for (unsigned int i = 0; i < encoded_nelts; i++)
sel.quick_push (build_int_cst (TREE_TYPE (type), indices[i]));
return sel.build ();
}
/* Return a CONST_VECTOR of mode MODE that contains the elements of
INDICES. */
rtx
vec_perm_indices_to_rtx (machine_mode mode, const vec_perm_indices &indices)
{
gcc_assert (GET_MODE_CLASS (mode) == MODE_VECTOR_INT
&& known_eq (GET_MODE_NUNITS (mode), indices.length ()));
rtx_vector_builder sel (mode, indices.encoding ().npatterns (),
indices.encoding ().nelts_per_pattern ());
unsigned int encoded_nelts = sel.encoded_nelts ();
for (unsigned int i = 0; i < encoded_nelts; i++)
sel.quick_push (gen_int_mode (indices[i], GET_MODE_INNER (mode)));
return sel.build ();
}
#if CHECKING_P
namespace selftest {
/* Test a 12-element vector. */
static void
test_vec_perm_12 (void)
{
vec_perm_builder builder (12, 12, 1);
for (unsigned int i = 0; i < 4; ++i)
{
builder.quick_push (i * 5);
builder.quick_push (3 + i);
builder.quick_push (2 + 3 * i);
}
vec_perm_indices indices (builder, 1, 12);
ASSERT_TRUE (indices.series_p (0, 3, 0, 5));
ASSERT_FALSE (indices.series_p (0, 3, 3, 5));
ASSERT_FALSE (indices.series_p (0, 3, 0, 8));
ASSERT_TRUE (indices.series_p (1, 3, 3, 1));
ASSERT_TRUE (indices.series_p (2, 3, 2, 3));
ASSERT_TRUE (indices.series_p (0, 4, 0, 4));
ASSERT_FALSE (indices.series_p (1, 4, 3, 4));
ASSERT_TRUE (indices.series_p (0, 6, 0, 10));
ASSERT_FALSE (indices.series_p (0, 6, 0, 100));
ASSERT_FALSE (indices.series_p (1, 10, 3, 7));
ASSERT_TRUE (indices.series_p (1, 10, 3, 8));
ASSERT_TRUE (indices.series_p (0, 12, 0, 10));
ASSERT_TRUE (indices.series_p (0, 12, 0, 11));
ASSERT_TRUE (indices.series_p (0, 12, 0, 100));
}
/* Run selftests for this file. */
void
vec_perm_indices_c_tests ()
{
test_vec_perm_12 ();
}
} // namespace selftest
#endif