/* A representation of vector permutation indices. Copyright (C) 2017-2018 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 . */ #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 (©_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