#include "config.h"#include "system.h"#include "coretypes.h"#include "backend.h"#include "rtl.h"#include "tree.h"#include "gimple.h"#include "cfghooks.h"#include "tree-pass.h"#include "ssa.h"#include "expmed.h"#include "gimple-pretty-print.h"#include "fold-const.h"#include "gimple-iterator.h"#include "gimplify-me.h"#include "stor-layout.h"#include "cfgloop.h"#include "tree-cfg.h"#include "domwalk.h"#include "tree-ssa-address.h"#include "tree-affine.h"#include "tree-eh.h"#include "builtins.h"
Data Structures | |
| class | slsr_cand_d |
| struct | cand_chain_d |
| class | incr_info_d |
| struct | cand_chain_hasher |
| class | find_candidates_dom_walker |
Enumerations | |
| enum | cand_kind { CAND_MULT , CAND_ADD , CAND_REF , CAND_PHI } |
| enum | cost_consts { COST_NEUTRAL = 0 , COST_INFINITE = 1000 } |
| enum | stride_status { UNKNOWN_STRIDE = 0 , KNOWN_STRIDE = 1 } |
| enum | phi_adjust_status { NOT_PHI_ADJUST = 0 , PHI_ADJUST = 1 } |
| enum | count_phis_status { DONT_COUNT_PHIS = 0 , COUNT_PHIS = 1 } |
Variables | |
| static vec< slsr_cand_t > | cand_vec |
| const int | MAX_SPREAD = 16 |
| static hash_map< gimple *, slsr_cand_t > * | stmt_cand_map |
| static struct obstack | cand_obstack |
| static struct obstack | chain_obstack |
| static incr_info_t | incr_vec |
| static unsigned | incr_vec_len |
| const int | MAX_INCR_VEC_LEN = 16 |
| static bool | address_arithmetic_p |
| static hash_table< cand_chain_hasher > * | base_cand_map |
| static hash_map< tree, name_expansion * > * | name_expansions |
| static hash_map< tree, tree > * | alt_base_map |
Typedef Documentation
◆ cand_chain
◆ cand_chain_t
◆ cand_idx
Straight-line strength reduction. Copyright (C) 2012-2024 Free Software Foundation, Inc. Contributed by Bill Schmidt, IBM <wschmidt@linux.ibm.com> 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/>.
There are many algorithms for performing strength reduction on loops. This is not one of them. IVOPTS handles strength reduction of induction variables just fine. This pass is intended to pick up the crumbs it leaves behind, by considering opportunities for strength reduction along dominator paths. Strength reduction addresses explicit multiplies, and certain multiplies implicit in addressing expressions. It would also be possible to apply strength reduction to divisions and modulos, but such opportunities are relatively uncommon. Strength reduction is also currently restricted to integer operations. If desired, it could be extended to floating-point operations under control of something like -funsafe-math-optimizations.
Information about a strength reduction candidate. Each statement
in the candidate table represents an expression of one of the
following forms (the special case of CAND_REF will be described
later):
(CAND_MULT) S1: X = (B + i) * S
(CAND_ADD) S1: X = B + (i * S)
Here X and B are SSA names, i is an integer constant, and S is
either an SSA name or a constant. We call B the "base," i the
"index", and S the "stride."
Any statement S0 that dominates S1 and is of the form:
(CAND_MULT) S0: Y = (B + i') * S
(CAND_ADD) S0: Y = B + (i' * S)
is called a "basis" for S1. In both cases, S1 may be replaced by
S1': X = Y + (i - i') * S,
where (i - i') * S is folded to the extent possible.
All gimple statements are visited in dominator order, and each
statement that may contribute to one of the forms of S1 above is
given at least one entry in the candidate table. Such statements
include addition, pointer addition, subtraction, multiplication,
negation, copies, and nontrivial type casts. If a statement may
represent more than one expression of the forms of S1 above,
multiple "interpretations" are stored in the table and chained
together. Examples:
* An add of two SSA names may treat either operand as the base.
* A multiply of two SSA names, likewise.
* A copy or cast may be thought of as either a CAND_MULT with
i = 0 and S = 1, or as a CAND_ADD with i = 0 or S = 0.
Candidate records are allocated from an obstack. They are addressed
both from a hash table keyed on S1, and from a vector of candidate
pointers arranged in predominator order.
Opportunity note
----------------
Currently we don't recognize:
S0: Y = (S * i') - B
S1: X = (S * i) - B
as a strength reduction opportunity, even though this S1 would
also be replaceable by the S1' above. This can be added if it
comes up in practice.
Strength reduction in addressing
--------------------------------
There is another kind of candidate known as CAND_REF. A CAND_REF
describes a statement containing a memory reference having
complex addressing that might benefit from strength reduction.
Specifically, we are interested in references for which
get_inner_reference returns a base address, offset, and bitpos as
follows:
base: MEM_REF (T1, C1)
offset: MULT_EXPR (PLUS_EXPR (T2, C2), C3)
bitpos: C4 * BITS_PER_UNIT
Here T1 and T2 are arbitrary trees, and C1, C2, C3, C4 are
arbitrary integer constants. Note that C2 may be zero, in which
case the offset will be MULT_EXPR (T2, C3).
When this pattern is recognized, the original memory reference
can be replaced with:
MEM_REF (POINTER_PLUS_EXPR (T1, MULT_EXPR (T2, C3)),
C1 + (C2 * C3) + C4)
which distributes the multiply to allow constant folding. When
two or more addressing expressions can be represented by MEM_REFs
of this form, differing only in the constants C1, C2, and C4,
making this substitution produces more efficient addressing during
the RTL phases. When there are not at least two expressions with
the same values of T1, T2, and C3, there is nothing to be gained
by the replacement.
Strength reduction of CAND_REFs uses the same infrastructure as
that used by CAND_MULTs and CAND_ADDs. We record T1 in the base (B)
field, MULT_EXPR (T2, C3) in the stride (S) field, and
C1 + (C2 * C3) + C4 in the index (i) field. A basis for a CAND_REF
is thus another CAND_REF with the same B and S values. When at
least two CAND_REFs are chained together using the basis relation,
each of them is replaced as above, resulting in improved code
generation for addressing.
Conditional candidates
======================
Conditional candidates are best illustrated with an example.
Consider the code sequence:
(1) x_0 = ...;
(2) a_0 = x_0 * 5; MULT (B: x_0; i: 0; S: 5)
if (...)
(3) x_1 = x_0 + 1; ADD (B: x_0, i: 1; S: 1)
(4) x_2 = PHI <x_0, x_1>; PHI (B: x_0, i: 0, S: 1)
(5) x_3 = x_2 + 1; ADD (B: x_2, i: 1, S: 1)
(6) a_1 = x_3 * 5; MULT (B: x_2, i: 1; S: 5)
Here strength reduction is complicated by the uncertain value of x_2.
A legitimate transformation is:
(1) x_0 = ...;
(2) a_0 = x_0 * 5;
if (...)
{
(3) [x_1 = x_0 + 1;]
(3a) t_1 = a_0 + 5;
}
(4) [x_2 = PHI <x_0, x_1>;]
(4a) t_2 = PHI <a_0, t_1>;
(5) [x_3 = x_2 + 1;]
(6r) a_1 = t_2 + 5;
where the bracketed instructions may go dead.
To recognize this opportunity, we have to observe that statement (6)
has a "hidden basis" (2). The hidden basis is unlike a normal basis
in that the statement and the hidden basis have different base SSA
names (x_2 and x_0, respectively). The relationship is established
when a statement's base name (x_2) is defined by a phi statement (4),
each argument of which (x_0, x_1) has an identical "derived base name."
If the argument is defined by a candidate (as x_1 is by (3)) that is a
CAND_ADD having a stride of 1, the derived base name of the argument is
the base name of the candidate (x_0). Otherwise, the argument itself
is its derived base name (as is the case with argument x_0).
The hidden basis for statement (6) is the nearest dominating candidate
whose base name is the derived base name (x_0) of the feeding phi (4),
and whose stride is identical to that of the statement. We can then
create the new "phi basis" (4a) and feeding adds along incoming arcs (3a),
allowing the final replacement of (6) by the strength-reduced (6r).
To facilitate this, a new kind of candidate (CAND_PHI) is introduced.
A CAND_PHI is not a candidate for replacement, but is maintained in the
candidate table to ease discovery of hidden bases. Any phi statement
whose arguments share a common derived base name is entered into the
table with the derived base name, an (arbitrary) index of zero, and a
stride of 1. A statement with a hidden basis can then be detected by
simply looking up its feeding phi definition in the candidate table,
extracting the derived base name, and searching for a basis in the
usual manner after substituting the derived base name.
Note that the transformation is only valid when the original phi and
the statements that define the phi's arguments are all at the same
position in the loop hierarchy. Index into the candidate vector, offset by 1. VECs are zero-based, while cand_idx's are one-based, with zero indicating null.
◆ const_cand_chain_t
◆ const_slsr_cand_t
◆ incr_info
◆ incr_info_t
◆ slsr_cand
◆ slsr_cand_t
Enumeration Type Documentation
◆ cand_kind
◆ cost_consts
◆ count_phis_status
◆ phi_adjust_status
◆ stride_status
Function Documentation
◆ add_cand_for_stmt()
|
static |
Add an entry to the statement-to-candidate mapping.
References gcc_assert, ggc_alloc(), and stmt_cand_map.
Referenced by slsr_process_add(), slsr_process_cast(), slsr_process_copy(), slsr_process_mul(), slsr_process_neg(), slsr_process_phi(), and slsr_process_ref().
◆ all_phi_incrs_profitable()
|
static |
Return TRUE iff all required increments for candidates feeding PHI are profitable (and legal!) to replace on behalf of candidate C.
References all_phi_incrs_profitable_1(), clear_visited(), and ggc_alloc().
Referenced by replace_profitable_candidates().
◆ all_phi_incrs_profitable_1()
|
static |
Recursive helper function for all_phi_incrs_profitable.
References address_arithmetic_p, all_phi_incrs_profitable_1(), base_cand_from_table(), CDI_DOMINATORS, dominated_by_p(), dump_file, dump_flags, ggc_alloc(), gimple_bb(), gimple_phi_arg_def(), gimple_phi_arg_edge(), gimple_phi_num_args(), i, incr_vec, incr_vec_index(), lookup_cand(), MAX_SPREAD, wi::neg_p(), operand_equal_p(), print_decs(), print_gimple_stmt(), profitable_increment_p(), SSA_NAME_DEF_STMT, stmt_cand_map, and TDF_DETAILS.
Referenced by all_phi_incrs_profitable(), and all_phi_incrs_profitable_1().
◆ alloc_cand_and_find_basis()
|
static |
Allocate storage for a new candidate and initialize its fields. Attempt to find a basis for the candidate. For CAND_REF, an alternative base may also be recorded and used to find a basis. This helps cases where the expression hidden behind BASE (which is usually an SSA_NAME) has immediate offset, e.g. a2[i][j] = 1; a2[i + 20][j] = 2;
References CAND_MULT, cand_obstack, CAND_PHI, CAND_REF, cand_vec, find_basis_for_candidate(), find_phi_def(), get_alternative_base(), ggc_alloc(), NULL_TREE, and record_potential_basis().
Referenced by create_add_imm_cand(), create_add_ssa_cand(), create_mul_imm_cand(), create_mul_ssa_cand(), slsr_process_cast(), slsr_process_copy(), slsr_process_phi(), and slsr_process_ref().
◆ analyze_candidates_and_replace()
Analyze costs of related candidates in the candidate vector, and make beneficial replacements.
References address_arithmetic_p, analyze_increments(), CAND_ADD, CAND_REF, cand_vec, count_candidates(), dump_file, dump_flags, dump_incr_vec(), FOR_EACH_VEC_ELT_FROM, free(), ggc_alloc(), gimple_assign_lhs(), gsi_commit_edge_inserts(), i, incr_vec, incr_vec_len, insert_initializers(), lookup_cand(), MAX_INCR_VEC_LEN, optimize_cands_for_speed_p(), POINTER_TYPE_P, record_increments(), replace_profitable_candidates(), replace_refs(), replace_uncond_cands_and_profitable_phis(), TDF_DETAILS, TREE_CODE, TREE_TYPE, and TYPE_MODE.
◆ analyze_increments()
|
static |
Use target-specific costs to determine and record which increments in the current candidate tree are profitable to replace, assuming MODE and SPEED. FIRST_DEP is the first dependent of the root of the candidate tree. One slight limitation here is that we don't account for the possible introduction of casts in some cases. See replace_one_candidate for the cases where these are introduced. This should probably be cleaned up sometime.
References add_cost(), CAND_MULT, COST_INFINITE, COST_NEUTRAL, count, COUNT_PHIS, DONT_COUNT_PHIS, wi::fits_shwi_p(), ggc_alloc(), gimple_assign_lhs(), i, incr_vec, incr_vec_len, legal_cast_p_1(), lowest_cost_path(), mul_cost(), mult_by_coeff_cost(), POINTER_TYPE_P, total_savings(), TREE_CODE, tree_fits_shwi_p(), tree_to_shwi(), and TREE_TYPE.
Referenced by analyze_candidates_and_replace().
◆ backtrace_base_for_ref()
|
static |
Given PBASE which is a pointer to tree, look up the defining statement for it and check whether the candidate is in the form of: X = B + (1 * S), S is integer constant X = B + (i * S), S is integer one If so, set PBASE to the candidate's base_expr and return double int (i * S). Otherwise, just return double int zero.
References base_cand_from_table(), CAND_ADD, CAND_PHI, CONVERT_EXPR_P, get_unwidened(), ggc_alloc(), integer_onep(), legal_cast_p_1(), lookup_cand(), NULL_TREE, STRIP_NOPS, wi::to_offset(), TREE_CODE, TREE_OPERAND, and TREE_TYPE.
Referenced by restructure_reference().
◆ base_cand_from_table()
|
static |
Forward function declarations.
Look up the defining statement for BASE_IN and return a pointer to its candidate in the candidate table, if any; otherwise NULL. Only CAND_ADD and CAND_MULT candidates are returned.
References CAND_REF, ggc_alloc(), NULL, SSA_NAME_DEF_STMT, and stmt_cand_map.
Referenced by all_phi_incrs_profitable_1(), backtrace_base_for_ref(), create_add_imm_cand(), create_add_ssa_cand(), create_mul_imm_cand(), create_mul_ssa_cand(), create_phi_basis_1(), find_phi_def(), ncd_with_phi(), phi_add_costs_1(), phi_incr_cost_1(), record_phi_increments_1(), slsr_process_cast(), slsr_process_copy(), and slsr_process_phi().
◆ cand_abs_increment()
|
inlinestatic |
Calculate the increment required for candidate C relative to its basis. If we aren't going to generate pointer arithmetic for this candidate, return the absolute value of that increment instead.
References address_arithmetic_p, cand_increment(), ggc_alloc(), and wi::neg_p().
Referenced by lowest_cost_path(), ncd_of_cand_and_phis(), replace_profitable_candidates(), and total_savings().
◆ cand_already_replaced()
|
inlinestatic |
Return TRUE iff candidate C has already been replaced under another interpretation.
References gimple_bb().
Referenced by count_candidates(), lowest_cost_path(), nearest_common_dominator_for_cands(), record_increments(), replace_profitable_candidates(), replace_unconditional_candidate(), total_savings(), and unreplaced_cand_in_tree().
◆ cand_increment()
|
static |
Calculate the increment required for candidate C relative to its basis.
References gcc_assert, lookup_cand(), operand_equal_p(), and phi_dependent_cand_p().
Referenced by cand_abs_increment(), record_increments(), replace_one_candidate(), and replace_unconditional_candidate().
◆ clear_visited()
Clear the visited field for a tree of PHI candidates.
References clear_visited(), ggc_alloc(), gimple_phi_arg_def(), gimple_phi_num_args(), i, SSA_NAME_DEF_STMT, and stmt_cand_map.
Referenced by all_phi_incrs_profitable(), clear_visited(), create_phi_basis(), phi_add_costs(), phi_incr_cost(), and record_phi_increments().
◆ count_candidates()
|
static |
Count the number of candidates in the tree rooted at C that have not already been replaced under other interpretations.
References cand_already_replaced(), count, count_candidates(), and lookup_cand().
Referenced by analyze_candidates_and_replace(), and count_candidates().
◆ create_add_imm_cand()
|
static |
Create a candidate entry for a statement GS, where GS adds SSA name BASE_IN to constant INDEX_IN. Propagate any known information about BASE_IN into the new candidate. Return the new candidate.
References alloc_cand_and_find_basis(), base_cand_from_table(), CAND_ADD, CAND_PHI, ggc_alloc(), has_single_use(), integer_one_node, lookup_cand(), wi::multiple_of_p(), NULL_TREE, sizetype, stmt_cost(), wi::to_offset(), TREE_CODE, TREE_TYPE, and TYPE_SIGN.
Referenced by slsr_process_add().
◆ create_add_on_incoming_edge()
|
static |
Create a new statement along edge E to add BASIS_NAME to the product of INCREMENT and the stride of candidate C. Create and return a new SSA name from *VAR to be used as the LHS of the new statement. KNOWN_STRIDE is true iff C's stride is a constant.
References dump_file, dump_flags, gcc_assert, gcc_unreachable, ggc_alloc(), gimple_build_assign(), gimple_set_location(), gsi_insert_on_edge(), i, incr_vec, incr_vec_index(), make_temp_ssa_name(), wi::neg_p(), NULL, POINTER_TYPE_P, print_gimple_stmt(), sizetype, TDF_DETAILS, wi::to_offset(), TREE_TYPE, types_compatible_p(), and wide_int_to_tree().
Referenced by create_phi_basis_1().
◆ create_add_ssa_cand()
|
static |
Create a candidate entry for a statement GS, where GS adds two SSA names BASE_IN and ADDEND_IN if SUBTRACT_P is false, and subtracts ADDEND_IN from BASE_IN otherwise. Propagate any known information about the two SSA names into the new candidate. Return the new candidate.
References alloc_cand_and_find_basis(), base_cand_from_table(), CAND_ADD, CAND_MULT, CAND_PHI, ggc_alloc(), has_single_use(), integer_zero_node, lookup_cand(), NULL_TREE, operand_equal_p(), sizetype, stmt_cost(), wi::to_offset(), TREE_CODE, and TREE_TYPE.
Referenced by slsr_process_add().
◆ create_mul_imm_cand()
|
static |
Create a candidate entry for a statement GS, where GS multiplies SSA name BASE_IN by constant STRIDE_IN. Propagate any known information about BASE_IN into the new candidate. Return the new candidate.
References alloc_cand_and_find_basis(), base_cand_from_table(), CAND_ADD, CAND_MULT, CAND_PHI, wi::fits_to_tree_p(), ggc_alloc(), has_single_use(), integer_onep(), lookup_cand(), NULL_TREE, sizetype, stmt_cost(), wi::to_offset(), TREE_CODE, TREE_TYPE, and wide_int_to_tree().
Referenced by slsr_process_mul(), and slsr_process_neg().
◆ create_mul_ssa_cand()
|
static |
Create a candidate entry for a statement GS, where GS multiplies two SSA names BASE_IN and STRIDE_IN. Propagate any known information about the two SSA names into the new candidate. Return the new candidate.
References alloc_cand_and_find_basis(), base_cand_from_table(), CAND_ADD, CAND_MULT, CAND_PHI, ggc_alloc(), has_single_use(), integer_onep(), lookup_cand(), NULL_TREE, stmt_cost(), wi::to_offset(), TREE_CODE, and TREE_TYPE.
Referenced by slsr_process_mul().
◆ create_phi_basis()
|
static |
Given a candidate C with BASIS_NAME being the LHS of C's basis which is hidden by the phi node FROM_PHI, create a new phi node in the same block as FROM_PHI. The new phi is suitable for use as a basis by C, with its phi arguments representing conditional adjustments to the hidden basis along conditional incoming paths. Those adjustments are made by creating add statements (and sometimes recursively creating phis) along those incoming paths. LOC is the location to attach to the introduced statements. KNOWN_STRIDE is true iff C's stride is a constant.
References clear_visited(), create_phi_basis_1(), gcc_assert, and ggc_alloc().
Referenced by replace_conditional_candidate(), and replace_profitable_candidates().
◆ create_phi_basis_1()
|
static |
Recursive helper function for create_phi_basis.
References add_phi_arg(), base_cand_from_table(), create_add_on_incoming_edge(), create_phi_basis_1(), create_phi_node(), dump_file, dump_flags, FOR_EACH_VEC_ELT, ggc_alloc(), gimple_assign_lhs(), gimple_bb(), gimple_phi_arg_def(), gimple_phi_num_args(), i, lookup_cand(), make_temp_ssa_name(), NULL, operand_equal_p(), print_gimple_stmt(), SSA_NAME_DEF_STMT, stmt_cand_map, TDF_DETAILS, TREE_TYPE, and update_stmt().
Referenced by create_phi_basis(), and create_phi_basis_1().
◆ dump_cand_chains()
Dump the candidate chains.
References base_cand_map, dump_file, ggc_alloc(), NULL, and ssa_base_cand_dump_callback().
◆ dump_cand_vec()
Dump the candidate vector for debug.
References cand_vec, dump_candidate(), dump_file, FOR_EACH_VEC_ELT, ggc_alloc(), i, and NULL.
◆ dump_candidate()
|
static |
Dump a candidate for debug.
References CAND_ADD, CAND_MULT, CAND_PHI, CAND_REF, dump_file, gcc_unreachable, ggc_alloc(), gimple_bb(), basic_block_def::index, print_decs(), print_generic_expr(), print_gimple_stmt(), TREE_CODE, and TREE_TYPE.
Referenced by dump_cand_vec().
◆ dump_incr_vec()
Dump the increment vector for debug.
References count, dump_file, dump_flags, ggc_alloc(), i, incr_vec, incr_vec_len, print_decs(), print_generic_expr(), and TDF_DETAILS.
Referenced by analyze_candidates_and_replace().
◆ find_basis_for_base_expr()
|
static |
Helper routine for find_basis_for_candidate. May be called twice: once for the candidate's base expr, and optionally again either for the candidate's phi definition or for a CAND_REF's alternative base expression.
References base_cand_map, CDI_DOMINATORS, dominated_by_p(), ggc_alloc(), gimple_assign_lhs(), gimple_bb(), NULL, operand_equal_p(), SSA_NAME_OCCURS_IN_ABNORMAL_PHI, TREE_CODE, and types_compatible_p().
Referenced by find_basis_for_candidate().
◆ find_basis_for_candidate()
|
static |
Use the base expr from candidate C to look for possible candidates that can serve as a basis for C. Each potential basis must also appear in a block that dominates the candidate statement and have the same stride and type. If more than one possible basis exists, the one with highest index in the vector is chosen; this will be the most immediately dominating basis.
References CAND_REF, CDI_DOMINATORS, dominated_by_p(), find_basis_for_base_expr(), get_alternative_base(), ggc_alloc(), gimple_bb(), gimple_phi_result(), lookup_cand(), NULL, and uses_consumed_by_stmt().
Referenced by alloc_cand_and_find_basis().
◆ find_phi_def()
Look in the candidate table for a CAND_PHI that defines BASE and return it if found; otherwise return NULL.
References base_cand_from_table(), CAND_PHI, gimple_phi_result(), SSA_NAME_OCCURS_IN_ABNORMAL_PHI, and TREE_CODE.
Referenced by alloc_cand_and_find_basis().
◆ get_alternative_base()
Given BASE, use the tree affine combiniation facilities to find the underlying tree expression for BASE, with any immediate offset excluded. N.B. we should eliminate this backtracking with better forward analysis in a future release.
References aff_combination_to_tree(), alt_base_map, expr, gcc_assert, hash_map< KeyId, Value, Traits >::get(), ggc_alloc(), name_expansions, NULL, hash_map< KeyId, Value, Traits >::put(), tree_to_aff_combination_expand(), and TREE_TYPE.
Referenced by alloc_cand_and_find_basis(), and find_basis_for_candidate().
◆ incr_vec_index()
|
inlinestatic |
Return the index in the increment vector of the given INCREMENT, or -1 if not found. The latter can occur if more than MAX_INCR_VEC_LEN increments have been found.
References ggc_alloc(), i, incr_vec, and incr_vec_len.
Referenced by all_phi_incrs_profitable_1(), create_add_on_incoming_edge(), and replace_profitable_candidates().
◆ insert_initializers()
|
static |
For each profitable increment in the increment vector not equal to 0 or 1 (or -1, for non-pointer arithmetic), find the nearest common dominator of all statements in the candidate chain rooted at C that require that increment, and insert an initializer T_0 = stride * increment at that location. Record T_0 with the increment record.
References CDI_DOMINATORS, COST_INFINITE, dominated_by_p(), dump_file, dump_flags, ggc_alloc(), gimple_bb(), gimple_build_assign(), gimple_location(), gimple_set_location(), gsi_end_p(), gsi_for_stmt(), gsi_insert_after(), gsi_insert_before(), gsi_last_bb(), GSI_NEW_STMT, GSI_SAME_STMT, gsi_stmt(), i, incr_vec, incr_vec_len, lookup_cand(), make_temp_ssa_name(), nearest_common_dominator_for_cands(), NULL, POINTER_TYPE_P, print_gimple_stmt(), profitable_increment_p(), SSA_NAME_DEF_STMT, stmt_ends_bb_p(), TDF_DETAILS, TDF_NONE, TREE_TYPE, types_compatible_p(), and wide_int_to_tree().
Referenced by analyze_candidates_and_replace().
◆ introduce_cast_before_cand()
|
static |
Create a NOP_EXPR that copies FROM_EXPR into a new SSA name of type TO_TYPE, and insert it in front of the statement represented by candidate C. Use *NEW_VAR to create the new SSA name. Return the new SSA name.
References dump_file, dump_flags, ggc_alloc(), gimple_build_assign(), gimple_location(), gimple_set_location(), gsi_for_stmt(), gsi_insert_before(), GSI_SAME_STMT, make_temp_ssa_name(), NULL, print_gimple_stmt(), and TDF_DETAILS.
Referenced by replace_mult_candidate(), and replace_one_candidate().
◆ legal_cast_p()
Return TRUE if GS is a statement that defines an SSA name from a conversion and is legal for us to combine with an add and multiply in the candidate table. For example, suppose we have: A = B + i; C = (type) A; D = C * S; Without the type-cast, we would create a CAND_MULT for D with base B, index i, and stride S. We want to record this candidate only if it is equivalent to apply the type cast following the multiply: A = B + i; E = A * S; D = (type) E; We will record the type with the candidate for D. This allows us to use a similar previous candidate as a basis. If we have earlier seen A' = B + i'; C' = (type) A'; D' = C' * S; we can replace D with D = D' + (i - i') * S; But if moving the type-cast would change semantics, we mustn't do this. This is legitimate for casts from a non-wrapping integral type to any integral type of the same or larger size. It is not legitimate to convert a wrapping type to a non-wrapping type, or to a wrapping type of a different size. I.e., with a wrapping type, we must assume that the addition B + i could wrap, in which case performing the multiply before or after one of the "illegal" type casts will have different semantics.
References CONVERT_EXPR_CODE_P, ggc_alloc(), gimple_assign_lhs(), gimple_assign_rhs_code(), is_gimple_assign(), legal_cast_p_1(), and TREE_TYPE.
Referenced by slsr_process_cast().
◆ legal_cast_p_1()
Help function for legal_cast_p, operating on two trees. Checks whether it's allowable to cast from RHS to LHS. See legal_cast_p for more details.
References ANY_INTEGRAL_TYPE_P, ggc_alloc(), TYPE_OVERFLOW_WRAPS, and TYPE_PRECISION.
Referenced by analyze_increments(), backtrace_base_for_ref(), and legal_cast_p().
◆ lookup_cand()
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static |
Produce a pointer to the IDX'th candidate in the candidate vector.
References cand_vec.
Referenced by all_phi_incrs_profitable_1(), analyze_candidates_and_replace(), backtrace_base_for_ref(), cand_increment(), count_candidates(), create_add_imm_cand(), create_add_ssa_cand(), create_mul_imm_cand(), create_mul_ssa_cand(), create_phi_basis_1(), find_basis_for_candidate(), insert_initializers(), lowest_cost_path(), ncd_of_cand_and_phis(), ncd_with_phi(), nearest_common_dominator_for_cands(), phi_add_costs_1(), phi_dependent_cand_p(), phi_incr_cost_1(), record_increments(), replace_conditional_candidate(), replace_mult_candidate(), replace_one_candidate(), replace_profitable_candidates(), replace_refs(), replace_rhs_if_not_dup(), replace_uncond_cands_and_profitable_phis(), replace_unconditional_candidate(), slsr_process_cast(), slsr_process_copy(), slsr_process_phi(), total_savings(), and unreplaced_cand_in_tree().
◆ lowest_cost_path()
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static |
Add COST_IN to the lowest cost of any dependent path starting at candidate C or any of its siblings, counting only candidates along such paths with increment INCR. Assume that replacing a candidate reduces cost by REPL_SAVINGS. Also account for savings from any statements that would go dead. If COUNT_PHIS is true, include costs of introducing feeding statements for conditional candidates.
References cand_abs_increment(), cand_already_replaced(), ggc_alloc(), gimple_phi_result(), lookup_cand(), lowest_cost_path(), MIN, phi_dependent_cand_p(), phi_incr_cost(), and uses_consumed_by_stmt().
Referenced by analyze_increments(), and lowest_cost_path().
◆ make_pass_strength_reduction()
| gimple_opt_pass * make_pass_strength_reduction | ( | gcc::context * | ctxt | ) |
References ggc_alloc().
◆ ncd_for_two_cands()
|
static |
Return the nearest common dominator of BB1 and BB2. If the blocks are identical, return the earlier of C1 and C2 in *WHERE. Otherwise, if the NCD matches BB1, return C1 in *WHERE; if the NCD matches BB2, return C2 in *WHERE; and if the NCD matches neither, return NULL in *WHERE. Note: It is possible for one of C1 and C2 to be NULL.
References CDI_DOMINATORS, ggc_alloc(), nearest_common_dominator(), and NULL.
Referenced by ncd_with_phi(), and nearest_common_dominator_for_cands().
◆ ncd_of_cand_and_phis()
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static |
Consider the candidate C together with any candidates that feed C's phi dependence (if any). Find and return the nearest common dominator of those candidates requiring the given increment INCR. If the returned block contains one or more of the candidates, return the earliest candidate in the block in *WHERE.
References cand_abs_increment(), ggc_alloc(), gimple_bb(), lookup_cand(), ncd_with_phi(), NULL, and phi_dependent_cand_p().
Referenced by nearest_common_dominator_for_cands().
◆ ncd_with_phi()
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static |
Consider all candidates that feed PHI. Find the nearest common dominator of those candidates requiring the given increment INCR. Further find and return the nearest common dominator of this result with block NCD. If the returned block contains one or more of the candidates, return the earliest candidate in the block in *WHERE.
References address_arithmetic_p, base_cand_from_table(), ggc_alloc(), gimple_phi_arg_def(), gimple_phi_arg_edge(), gimple_phi_num_args(), i, lookup_cand(), ncd_for_two_cands(), ncd_with_phi(), NULL, operand_equal_p(), SSA_NAME_DEF_STMT, and stmt_cand_map.
Referenced by ncd_of_cand_and_phis(), and ncd_with_phi().
◆ nearest_common_dominator_for_cands()
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static |
Consider all candidates in the tree rooted at C for which INCR represents the required increment of C relative to its basis. Find and return the basic block that most nearly dominates all such candidates. If the returned block contains one or more of the candidates, return the earliest candidate in the block in *WHERE.
References cand_already_replaced(), ggc_alloc(), lookup_cand(), ncd_for_two_cands(), ncd_of_cand_and_phis(), nearest_common_dominator_for_cands(), and NULL.
Referenced by insert_initializers(), and nearest_common_dominator_for_cands().
◆ optimize_cands_for_speed_p()
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static |
Return TRUE if the candidates in the tree rooted at C should be optimized for speed, else FALSE. We estimate this based on the block containing the most dominant candidate in the tree that has not yet been replaced.
References gcc_assert, ggc_alloc(), gimple_bb(), optimize_bb_for_speed_p(), and unreplaced_cand_in_tree().
Referenced by analyze_candidates_and_replace().
◆ phi_add_costs()
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static |
Compute the expected costs of inserting basis adjustments for candidate C with phi-definition PHI. The cost of inserting one adjustment is given by ONE_ADD_COST. If PHI has arguments which are themselves phi results, recursively calculate costs for those phis as well.
References clear_visited(), ggc_alloc(), and phi_add_costs_1().
Referenced by replace_uncond_cands_and_profitable_phis().
◆ phi_add_costs_1()
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static |
Recursive helper function for phi_add_costs. SPREAD is a measure of how many PHI nodes we have visited at this point in the tree walk.
References base_cand_from_table(), CDI_DOMINATORS, COST_INFINITE, dominated_by_p(), ggc_alloc(), gimple_bb(), gimple_phi_arg_def(), gimple_phi_num_args(), i, lookup_cand(), MAX_SPREAD, phi_add_costs_1(), SSA_NAME_DEF_STMT, and stmt_cand_map.
Referenced by phi_add_costs(), and phi_add_costs_1().
◆ phi_dependent_cand_p()
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static |
Return TRUE if candidate C is dependent upon a PHI.
References lookup_cand().
Referenced by cand_increment(), lowest_cost_path(), ncd_of_cand_and_phis(), record_increments(), replace_profitable_candidates(), replace_uncond_cands_and_profitable_phis(), and total_savings().
◆ phi_incr_cost()
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static |
Add up and return the costs of introducing add statements that require the increment INCR on behalf of candidate C and phi statement PHI. Accumulate into *SAVINGS the potential savings from removing existing statements that feed PHI and have no other uses.
References clear_visited(), ggc_alloc(), and phi_incr_cost_1().
Referenced by lowest_cost_path(), and total_savings().
◆ phi_incr_cost_1()
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static |
Recursive helper function for phi_incr_cost.
References add_cost(), base_cand_from_table(), ggc_alloc(), gimple_assign_lhs(), gimple_phi_arg_def(), gimple_phi_num_args(), gimple_phi_result(), i, lookup_cand(), NULL, operand_equal_p(), phi_incr_cost_1(), SSA_NAME_DEF_STMT, stmt_cand_map, stmt_cost(), TREE_TYPE, TYPE_MODE, and uses_consumed_by_stmt().
Referenced by phi_incr_cost(), and phi_incr_cost_1().
◆ profitable_increment_p()
Return TRUE if the increment indexed by INDEX is profitable to replace.
References COST_NEUTRAL, incr_vec, and mem_address::index.
Referenced by all_phi_incrs_profitable_1(), insert_initializers(), and replace_profitable_candidates().
◆ record_increment()
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static |
Increase the count of INCREMENT by one in the increment vector. INCREMENT is associated with candidate C. If INCREMENT is to be conditionally executed as part of a conditional candidate replacement, IS_PHI_ADJUST is true, otherwise false. If an initializer T_0 = stride * I is provided by a candidate that dominates all candidates with the same increment, also record T_0 for subsequent use.
References address_arithmetic_p, CAND_ADD, CDI_DOMINATORS, COST_INFINITE, dominated_by_p(), ggc_alloc(), gimple_assign_rhs1(), gimple_assign_rhs2(), gimple_assign_rhs_code(), gimple_bb(), i, incr_vec, incr_vec_len, MAX_INCR_VEC_LEN, wi::neg_p(), NULL, NULL_TREE, operand_equal_p(), and SSA_NAME_DEF_STMT.
Referenced by record_increments(), and record_phi_increments_1().
◆ record_increments()
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static |
Determine how many times each unique increment occurs in the set of candidates rooted at C's parent, recording the data in the increment vector. For each unique increment I, if an initializer T_0 = stride * I is provided by a candidate that dominates all candidates with the same increment, also record T_0 for subsequent use.
References cand_already_replaced(), cand_increment(), lookup_cand(), NOT_PHI_ADJUST, phi_dependent_cand_p(), record_increment(), record_increments(), and record_phi_increments().
Referenced by analyze_candidates_and_replace(), and record_increments().
◆ record_phi_increments()
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static |
Given phi statement PHI that hides a candidate from its BASIS, find the increments along each incoming arc (recursively handling additional phis that may be present) and record them. These increments are the difference in index between the index-adjusting statements and the index of the basis.
References clear_visited(), ggc_alloc(), and record_phi_increments_1().
Referenced by record_increments().
◆ record_phi_increments_1()
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static |
Recursive helper function for record_phi_increments.
References base_cand_from_table(), ggc_alloc(), gimple_phi_arg_def(), gimple_phi_num_args(), i, operand_equal_p(), PHI_ADJUST, record_increment(), record_phi_increments_1(), SSA_NAME_DEF_STMT, and stmt_cand_map.
Referenced by record_phi_increments(), and record_phi_increments_1().
◆ record_potential_basis()
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static |
Record a mapping from BASE to C, indicating that C may potentially serve as a basis using that base expression. BASE may be the same as C->BASE_EXPR; alternatively BASE can be a different tree that share the underlining expression of C->BASE_EXPR.
References base_cand_map, cand_chain_d::base_expr, cand_chain_d::cand, chain_obstack, gcc_assert, ggc_alloc(), cand_chain_d::next, and NULL.
Referenced by alloc_cand_and_find_basis().
◆ replace_conditional_candidate()
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static |
Given a candidate C whose basis is hidden by at least one intervening phi, introduce a matching number of new phis to represent its basis adjusted by conditional increments along possible incoming paths. Then replace C as though it were an unconditional candidate, using the new basis.
References create_phi_basis(), ggc_alloc(), gimple_assign_lhs(), gimple_location(), KNOWN_STRIDE, lookup_cand(), replace_mult_candidate(), and wi::to_offset().
Referenced by replace_uncond_cands_and_profitable_phis().
◆ replace_mult_candidate()
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static |
Common logic used by replace_unconditional_candidate and replace_conditional_candidate.
References CONVERT_EXPR_CODE_P, dump_file, dump_flags, wi::ext(), ggc_alloc(), gimple_assign_lhs(), gimple_assign_rhs1(), gimple_assign_rhs2(), gimple_assign_rhs_code(), gimple_assign_set_rhs_with_ops(), gimple_build_assign(), gimple_location(), gimple_set_location(), gsi_for_stmt(), gsi_replace(), gsi_stmt(), introduce_cast_before_cand(), lookup_cand(), wi::neg_p(), NULL, operand_equal_p(), print_gimple_stmt(), TDF_DETAILS, TREE_TYPE, TYPE_PRECISION, TYPE_SIGN, update_stmt(), useless_type_conversion_p(), and wide_int_to_tree().
Referenced by replace_conditional_candidate(), and replace_unconditional_candidate().
◆ replace_one_candidate()
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static |
Strength-reduce the statement represented by candidate C by replacing it with an equivalent addition or subtraction. I is the index into the increment vector identifying C's increment. NEW_VAR is used to create a new SSA name if a cast needs to be introduced. BASIS_NAME is the rhs1 to use in creating the add/subtract.
References address_arithmetic_p, cand_increment(), dump_file, dump_flags, gcc_assert, gcc_unreachable, ggc_alloc(), gimple_assign_lhs(), gimple_assign_rhs1(), gimple_assign_rhs2(), gimple_assign_rhs_code(), gimple_assign_set_rhs_with_ops(), gimple_build_assign(), gimple_location(), gimple_set_location(), gsi_for_stmt(), gsi_replace(), gsi_stmt(), i, incr_vec, introduce_cast_before_cand(), lookup_cand(), NULL, operand_equal_p(), print_gimple_stmt(), replace_rhs_if_not_dup(), TDF_DETAILS, TREE_TYPE, types_compatible_p(), and update_stmt().
Referenced by replace_profitable_candidates().
◆ replace_profitable_candidates()
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static |
For each candidate in the tree rooted at C, replace it with an increment if such has been shown to be profitable.
References all_phi_incrs_profitable(), cand_abs_increment(), cand_already_replaced(), CONVERT_EXPR_CODE_P, create_phi_basis(), ggc_alloc(), gimple_assign_lhs(), gimple_assign_rhs_code(), gimple_location(), i, incr_vec_index(), lookup_cand(), phi_dependent_cand_p(), profitable_increment_p(), replace_one_candidate(), replace_profitable_candidates(), and UNKNOWN_STRIDE.
Referenced by analyze_candidates_and_replace(), and replace_profitable_candidates().
◆ replace_ref()
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static |
Replace *EXPR in candidate C with an equivalent strength-reduced data reference.
References build_aligned_type(), copy_ref_info(), fold_build2, force_gimple_operand_gsi(), get_object_alignment_1(), ggc_alloc(), gsi_for_stmt(), GSI_SAME_STMT, least_bit_hwi(), NULL, TREE_OPERAND, TREE_TYPE, TYPE_ALIGN, update_stmt(), and wide_int_to_tree().
Referenced by replace_refs().
◆ replace_refs()
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static |
Replace CAND_REF candidate C, each sibling of candidate C, and each dependent of candidate C with an equivalent strength-reduced data reference.
References dump_file, dump_flags, ggc_alloc(), gimple_assign_lhs_ptr(), gimple_assign_rhs1_ptr(), gimple_vdef(), lookup_cand(), print_gimple_stmt(), replace_ref(), replace_refs(), TDF_DETAILS, and valid_mem_ref_cand_p().
Referenced by analyze_candidates_and_replace(), and replace_refs().
◆ replace_rhs_if_not_dup()
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static |
Replace the RHS of the statement represented by candidate C with NEW_CODE, NEW_RHS1, and NEW_RHS2, provided that to do so doesn't leave C unchanged or just interchange its operands. The original operation and operands are in OLD_CODE, OLD_RHS1, and OLD_RHS2. If the replacement was made and we are doing a details dump, return the revised statement, else NULL.
References dump_file, dump_flags, ggc_alloc(), gimple_assign_set_rhs_with_ops(), gsi_for_stmt(), gsi_stmt(), lookup_cand(), NULL, operand_equal_p(), TDF_DETAILS, and update_stmt().
Referenced by replace_one_candidate().
◆ replace_uncond_cands_and_profitable_phis()
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static |
For candidate C, each sibling of candidate C, and each dependent of candidate C, determine whether the candidate is dependent upon a phi that hides its basis. If not, replace the candidate unconditionally. Otherwise, determine whether the cost of introducing compensation code for the candidate is offset by the gains from strength reduction. If so, replace the candidate and introduce the compensation code.
References add_cost(), CAND_MULT, COST_NEUTRAL, dump_file, dump_flags, ggc_alloc(), gimple_bb(), gimple_phi_result(), lookup_cand(), optimize_bb_for_speed_p(), phi_add_costs(), phi_dependent_cand_p(), replace_conditional_candidate(), replace_uncond_cands_and_profitable_phis(), replace_unconditional_candidate(), stmt_cost(), TDF_DETAILS, wi::to_offset(), TREE_TYPE, and TYPE_MODE.
Referenced by analyze_candidates_and_replace(), and replace_uncond_cands_and_profitable_phis().
◆ replace_unconditional_candidate()
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static |
Replace candidate C with an add or subtract. Note that we only operate on CAND_MULTs with known strides, so we will never generate a POINTER_PLUS_EXPR. Each candidate X = (B + i) * S is replaced by X = Y + ((i - i') * S), as described in the module commentary. The folded value ((i - i') * S) is referred to here as the "bump."
References cand_already_replaced(), cand_increment(), ggc_alloc(), gimple_assign_lhs(), lookup_cand(), replace_mult_candidate(), and wi::to_offset().
Referenced by replace_uncond_cands_and_profitable_phis().
◆ restructure_reference()
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static |
Look for the following pattern:
*PBASE: MEM_REF (T1, C1)
*POFFSET: MULT_EXPR (T2, C3) [C2 is zero]
or
MULT_EXPR (PLUS_EXPR (T2, C2), C3)
or
MULT_EXPR (MINUS_EXPR (T2, -C2), C3)
*PINDEX: C4 * BITS_PER_UNIT
If not present, leave the input values unchanged and return FALSE.
Otherwise, modify the input values as follows and return TRUE:
*PBASE: T1
*POFFSET: MULT_EXPR (T2, C3)
*PINDEX: C1 + (C2 * C3) + C4
When T2 is recorded by a CAND_ADD in the form of (T2' + C5), it
will be further restructured to:
*PBASE: T1
*POFFSET: MULT_EXPR (T2', C3)
*PINDEX: C1 + (C2 * C3) + C4 + (C5 * C3)
References backtrace_base_for_ref(), fold_build2, fold_convert, ggc_alloc(), mem_ref_offset(), offset, SIGNED, sizetype, wi::to_offset(), TREE_CODE, TREE_OPERAND, TREE_TYPE, type(), wi::umod_floor(), and wide_int_to_tree().
Referenced by slsr_process_ref().
◆ slsr_process_add()
Given GS which is an add or subtract of scalar integers or pointers, make at least one appropriate entry in the candidate table.
References add_cand_for_stmt(), create_add_imm_cand(), create_add_ssa_cand(), ggc_alloc(), gimple_assign_rhs_code(), NULL, operand_equal_p(), POINTER_TYPE_P, wi::to_offset(), TREE_CODE, and TREE_TYPE.
Referenced by find_candidates_dom_walker::before_dom_children().
◆ slsr_process_cast()
Given GS which is a cast to a scalar integer type, determine whether the cast is legal for strength reduction. If so, make at least one appropriate entry in the candidate table.
References add_cand_for_stmt(), alloc_cand_and_find_basis(), base_cand_from_table(), CAND_ADD, CAND_MULT, CAND_PHI, ggc_alloc(), gimple_assign_lhs(), has_single_use(), integer_one_node, legal_cast_p(), lookup_cand(), NULL, sizetype, stmt_cost(), and TREE_TYPE.
Referenced by find_candidates_dom_walker::before_dom_children().
◆ slsr_process_copy()
Given GS which is a copy of a scalar integer type, make at least one appropriate entry in the candidate table. This interface is included for completeness, but is unnecessary if this pass immediately follows a pass that performs copy propagation, such as DOM.
References add_cand_for_stmt(), alloc_cand_and_find_basis(), base_cand_from_table(), CAND_ADD, CAND_MULT, CAND_PHI, ggc_alloc(), has_single_use(), integer_one_node, lookup_cand(), NULL, sizetype, stmt_cost(), and TREE_TYPE.
Referenced by find_candidates_dom_walker::before_dom_children().
◆ slsr_process_mul()
Given GS which is a multiply of scalar integers, make an appropriate entry in the candidate table. If this is a multiply of two SSA names, create two CAND_MULT interpretations and attempt to find a basis for each of them. Otherwise, create a single CAND_MULT and attempt to find a basis.
References add_cand_for_stmt(), create_mul_imm_cand(), create_mul_ssa_cand(), ggc_alloc(), integer_zerop(), and TREE_CODE.
Referenced by find_candidates_dom_walker::before_dom_children().
◆ slsr_process_neg()
Given GS which is a negate of a scalar integer, make an appropriate entry in the candidate table. A negate is equivalent to a multiply by -1.
References add_cand_for_stmt(), create_mul_imm_cand(), ggc_alloc(), and integer_minus_one_node.
Referenced by find_candidates_dom_walker::before_dom_children().
◆ slsr_process_phi()
Given PHI which contains a phi statement, determine whether it satisfies all the requirements of a phi candidate. If so, create a candidate. Note that a CAND_PHI never has a basis itself, but is used to help find a basis for subsequent candidates.
References add_cand_for_stmt(), alloc_cand_and_find_basis(), base_cand_from_table(), CAND_ADD, CAND_PHI, cfun, ENTRY_BLOCK_PTR_FOR_FN, ggc_alloc(), gimple_bb(), gimple_phi_arg_def(), gimple_phi_num_args(), i, integer_one_node, integer_onep(), lookup_cand(), basic_block_def::loop_father, NULL, NULL_TREE, operand_equal_p(), single_succ(), sizetype, SSA_NAME_IS_DEFAULT_DEF, stmt_cost(), TREE_CODE, TREE_TYPE, and uses_consumed_by_stmt().
Referenced by find_candidates_dom_walker::before_dom_children().
◆ slsr_process_ref()
Given GS which contains a data reference, create a CAND_REF entry in the candidate table and attempt to find a basis.
References add_cand_for_stmt(), alloc_cand_and_find_basis(), CAND_REF, DECL_BIT_FIELD, get_inner_reference(), ggc_alloc(), gimple_assign_lhs(), gimple_assign_rhs1(), gimple_vdef(), handled_component_p(), poly_int< N, C >::is_constant(), offset, restructure_reference(), sizetype, TREE_CODE, TREE_OPERAND, and type().
Referenced by find_candidates_dom_walker::before_dom_children().
◆ ssa_base_cand_dump_callback()
| int ssa_base_cand_dump_callback | ( | cand_chain ** | slot, |
| void * | ignored ) |
Callback used to dump the candidate chains hash table.
References cand_chain_d::cand, dump_file, ggc_alloc(), cand_chain_d::next, and print_generic_expr().
Referenced by dump_cand_chains().
◆ stmt_cost()
Determine the target cost of statement GS when compiling according to SPEED.
References add_cost(), CASE_CONVERT, convert_cost(), gcc_assert, gcc_unreachable, ggc_alloc(), gimple_assign_lhs(), gimple_assign_rhs1(), gimple_assign_rhs2(), gimple_assign_rhs_code(), is_gimple_assign(), mul_cost(), mult_by_coeff_cost(), neg_cost(), TREE_CODE, tree_fits_shwi_p(), tree_to_shwi(), TREE_TYPE, and TYPE_MODE.
Referenced by create_add_imm_cand(), create_add_ssa_cand(), create_mul_imm_cand(), create_mul_ssa_cand(), tree_loop_interchange::interchange(), phi_incr_cost_1(), replace_uncond_cands_and_profitable_phis(), slsr_process_cast(), slsr_process_copy(), and slsr_process_phi().
◆ total_savings()
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static |
Compute the total savings that would accrue from all replacements in the candidate tree rooted at C, counting only candidates with increment INCR. Assume that replacing a candidate reduces cost by REPL_SAVINGS. Also account for savings from statements that would go dead.
References cand_abs_increment(), cand_already_replaced(), ggc_alloc(), gimple_phi_result(), lookup_cand(), phi_dependent_cand_p(), phi_incr_cost(), total_savings(), and uses_consumed_by_stmt().
Referenced by analyze_increments(), and total_savings().
◆ unreplaced_cand_in_tree()
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static |
Return the first candidate in the tree rooted at C that has not already been replaced, favoring siblings over dependents.
References cand_already_replaced(), ggc_alloc(), lookup_cand(), NULL, and unreplaced_cand_in_tree().
Referenced by optimize_cands_for_speed_p(), and unreplaced_cand_in_tree().
◆ uses_consumed_by_stmt()
Determine whether all uses of NAME are directly or indirectly used by STMT. That is, we want to know whether if STMT goes dead, the definition of NAME also goes dead.
References FOR_EACH_IMM_USE_STMT, ggc_alloc(), gimple_get_lhs(), is_gimple_assign(), is_gimple_debug(), is_gimple_reg(), and uses_consumed_by_stmt().
Referenced by find_basis_for_candidate(), lowest_cost_path(), phi_incr_cost_1(), slsr_process_phi(), total_savings(), and uses_consumed_by_stmt().
◆ valid_mem_ref_cand_p()
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static |
Return true if CAND_REF candidate C is a valid memory reference.
References ggc_alloc(), NULL_TREE, sizetype, TREE_CODE, TREE_OPERAND, TYPE_ADDR_SPACE, TYPE_MODE, valid_mem_ref_p(), and wide_int_to_tree().
Referenced by replace_refs().
Variable Documentation
◆ address_arithmetic_p
|
static |
For a chain of candidates with unknown stride, indicates whether or not we must generate pointer arithmetic when replacing statements.
Referenced by all_phi_incrs_profitable_1(), analyze_candidates_and_replace(), cand_abs_increment(), ncd_with_phi(), record_increment(), and replace_one_candidate().
◆ alt_base_map
Pointer map embodying a mapping from bases to alternative bases.
Referenced by get_alternative_base().
◆ base_cand_map
|
static |
Hash table embodying a mapping from base exprs to chains of candidates.
Referenced by dump_cand_chains(), find_basis_for_base_expr(), and record_potential_basis().
◆ cand_obstack
Obstack for candidates.
Referenced by alloc_cand_and_find_basis().
◆ cand_vec
|
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Candidates are maintained in a vector. If candidate X dominates candidate Y, then X appears before Y in the vector; but the converse does not necessarily hold.
Referenced by alloc_cand_and_find_basis(), analyze_candidates_and_replace(), dump_cand_vec(), lookup_cand(), and undistribute_bitref_for_vector().
◆ chain_obstack
Obstack for candidate chains.
Referenced by record_potential_basis().
◆ incr_vec
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An array INCR_VEC of incr_infos is used during analysis of related candidates having an SSA name for a stride. INCR_VEC_LEN describes its current length. MAX_INCR_VEC_LEN is used to avoid costly pathological cases.
Referenced by all_phi_incrs_profitable_1(), analyze_candidates_and_replace(), analyze_increments(), create_add_on_incoming_edge(), dump_incr_vec(), incr_vec_index(), insert_initializers(), profitable_increment_p(), record_increment(), and replace_one_candidate().
◆ incr_vec_len
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◆ MAX_INCR_VEC_LEN
| const int MAX_INCR_VEC_LEN = 16 |
Referenced by analyze_candidates_and_replace(), and record_increment().
◆ MAX_SPREAD
| const int MAX_SPREAD = 16 |
Constrain how many PHI nodes we will visit for a conditional candidate (depth and breadth).
Referenced by all_phi_incrs_profitable_1(), and phi_add_costs_1().
◆ name_expansions
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Pointer map used by tree_to_aff_combination_expand.
Referenced by get_alternative_base().
◆ stmt_cand_map
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Pointer map embodying a mapping from statements to candidates.
Referenced by add_cand_for_stmt(), all_phi_incrs_profitable_1(), base_cand_from_table(), clear_visited(), create_phi_basis_1(), ncd_with_phi(), phi_add_costs_1(), phi_incr_cost_1(), and record_phi_increments_1().
