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1.8.1.1
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GCC Middle and Back End API Reference
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Data Structures | |
| struct | move |
Typedefs | |
| typedef void * | void_p |
| typedef struct move * | move_t |
Variables | |
| ira_emit_data_t | ira_allocno_emit_data |
| static vec< void_p > | new_allocno_emit_data_vec |
| static move_t * | at_bb_start |
| static move_t * | at_bb_end |
| static int | max_regno_before_changing |
| static bitmap | local_allocno_bitmap |
| static bitmap | used_regno_bitmap |
| static bitmap | renamed_regno_bitmap |
| static move_t | hard_regno_last_set [FIRST_PSEUDO_REGISTER] |
| static int | hard_regno_last_set_check [FIRST_PSEUDO_REGISTER] |
| static move_t * | allocno_last_set |
| static int * | allocno_last_set_check |
| static vec< move_t > | move_vec |
| static int | curr_tick |
| typedef void* void_p |
Definitions for vectors of pointers.
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Process moves from LIST with execution FREQ to add ranges, copies, and modify costs for allocnos involved in the moves. All regnos living through the list is in LIVE_THROUGH, and the loop tree node used to find corresponding allocnos is NODE.
This is a trick to guarantee that new ranges is not merged with
the old ones.
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Process all move list to add ranges, conflicts, copies, and modify costs for allocnos involved in the moves.
It does not matter what loop_tree_node (of source or
destination block) to use for searching allocnos by their
regnos because of subsequent IR flattening.
References free_move_list().
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Attach MOVE to the edge E. The move is attached to the head of the list if HEAD_P is TRUE.
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Change (if necessary) pseudo-registers inside loop given by loop tree node NODE.
We generate the same hard register move because the
reload pass can put an allocno into memory in this case
we will have live range splitting. If it does not happen
such the same hard register moves will be removed. The
worst case when the both allocnos are put into memory by
the reload is very rare. don't create copies because reload can spill an
allocno set by copy although the allocno will not
get memory slot. Rename locals: Local allocnos with same regno in different loops
might get the different hard register. So we need to change
ALLOCNO_REG.
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This recursive function changes pseudo-registers in *LOC if it is necessary. The function returns TRUE if a change was done.
It is a shared register which was changed already.
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Return new move of allocnos TO and FROM.
Referenced by modify_move_list().
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Create and return a new allocno with given REGNO and LOOP_TREE_NODE. Allocate emit data for it.
Referenced by modify_move_list().
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Generate RTX move insns from the move list LIST. This updates allocation cost using move execution frequency FREQ.
The reload needs to have set up insn codes. If the
reload sets up insn codes by itself, it may fail because
insns will have hard registers instead of pseudos and
there may be no machine insn with given hard
registers. Add insn to equiv init insn list if it is necessary.
Otherwise reload will not remove this insn if it decides
to use the equivalence.
References ira_load_cost.
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Generate RTX move insns from move lists attached to basic blocks and edges.
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Return true if there is an entry to given loop not from its parent (or grandparent) block. For example, it is possible for two adjacent loops inside another loop.
That is an exit from a nested loop -- skip it.
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Return TRUE if move lists on all edges given in vector VEC are equal.
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Return TRUE if the move list LIST1 and LIST2 are equal (two moves are equal if they involve the same allocnos).
References print_move_list().
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Free memory for MOVE and its dependencies.
References move::from, move::next, and move::to.
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Free memory for list of the moves given by its HEAD.
Referenced by add_ranges_and_copies(), and set_allocno_somewhere_renamed_p().
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Generate and attach moves to the edge E. This looks at the final regnos of allocnos living on the edge with the same original regno to figure out when moves should be generated.
Remove unnecessary stores at the region exit. We should do
this for readonly memory for sure and this is guaranteed by
that we never generate moves on region borders (see
checking in function change_loop).
| rtx ira_create_new_reg | ( | ) |
Create and return new pseudo-register with the same attributes as ORIGINAL_REG.
References ira_regno_allocno_map, and subloop_tree_node_p().
Referenced by modify_move_list().
| void ira_debug_move_list | ( | move_t | list | ) |
| void ira_debug_move_list | ( | ) |
Print move list LIST into stderr.
| void ira_emit | ( | ) |
The entry function changes code and generates shuffling allocnos on region borders for the regional (LOOPS_P is TRUE in this case) register allocation.
Clean up:
Fix insn codes. It is necessary to do it before reload because
reload assumes initial insn codes defined. The insn codes can be
invalidated by CFG infrastructure for example in jump
redirection.
Referenced by split_live_ranges_for_shrink_wrap().
| void ira_finish_emit_data | ( | void | ) |
Free the emit data.
References ira_free().
| void ira_initiate_emit_data | ( | void | ) |
Allocate and initiate the emit data.
Referenced by split_live_ranges_for_shrink_wrap().
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Remove unnecessary moves in the LIST, makes topological sorting, and removes cycles on hard reg dependencies by introducing new allocnos assigned to memory and additional moves. It returns the result move list.
Creat move deps.
Toplogical sorting:
Removing cycles:
It does not matter what loop_tree_node (of TO or
FROM) to use for the new allocno because of
subsequent IRA internal representation
flattening. Make it possibly conflicting with all earlier
created allocnos. Cases where temporary allocnos
created to remove the cycles are quite rare.
References allocno_emit_reg(), create_move(), create_new_allocno(), curr_tick, move::from, internal_flag_ira_verbose, ira_create_allocno_objects(), ira_create_new_reg(), ira_dump_file, ira_move_loops_num, ira_objects_num, ira_set_allocno_class(), and move::to.
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Print move list LIST into file F.
Referenced by eq_move_lists_p().
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Set up member `reg' to REG for allocnos which has the same regno as ALLOCNO and which are inside the loop corresponding to ALLOCNO.
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Process to set up flag somewhere_renamed_p.
References edge_def::aux, and free_move_list().
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Set up ENTERED_FROM_NON_PARENT_P for each loop region.
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Return TRUE if move of SRC_ALLOCNO (assigned to hard register) to DEST_ALLOCNO (assigned to memory) can be removed because it does not change value of the destination. One possible reason for this is the situation when SRC_ALLOCNO is not modified in the corresponding loop.
We achieved the destination and everything is ok.
If there is a path from a destination loop block to the
source loop header containing basic blocks of non-parents
(grandparents) of the source loop, we should have checked
modifications of the pseudo on this path too to decide
about possibility to remove the store. It could be done by
solving a data-flow problem. Unfortunately such global
solution would complicate IR flattening. Therefore we just
prohibit removal of the store in such complicated case. It is actually a loop entry -- do not remove the store.
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Return TRUE if loop given by SUBNODE inside the loop given by NODE.
References ira_loop_tree_node::parent, and ira_loop_tree_node::regno_allocno_map.
Referenced by ira_create_new_reg().
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This recursive function traverses dependencies of MOVE and produces topological sorting (in depth-first order).
Referenced by unify_moves().
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Look at all entry edges (if START_P) or exit edges of basic block BB and put move lists at the BB start or end if it is possible. In other words, this decreases code duplication of allocno moves.
References move::deps, move::deps_num, traverse_moves(), and move::visited_p.
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Update costs of A and corresponding allocnos on upper levels on the loop tree from reading (if READ_P) or writing A on an execution path with FREQ.
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Last move (in move sequence being processed) setting up the corresponding allocno.
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If the element value is equal to CURR_TICK then the corresponding element in . `allocno_last_set' is defined and correct.
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Array of moves (indexed by BB index) which should be put at the start/end of the corresponding basic blocks.
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The variable value is used to check correctness of values of elements of arrays `hard_regno_last_set' and `allocno_last_set_check'.
Referenced by modify_move_list().
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Last move (in move sequence being processed) setting up the corresponding hard register.
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If the element value is equal to CURR_TICK then the corresponding element in `hard_regno_last_set' is defined and correct.
| ira_emit_data_t ira_allocno_emit_data |
@verbatim
Integrated Register Allocator. Changing code and generating moves. Copyright (C) 2006-2013 Free Software Foundation, Inc. Contributed by Vladimir Makarov vmakarov@redhat.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/.
When we have more one region, we need to change the original RTL code after coloring. Let us consider two allocnos representing the same pseudo-register outside and inside a region respectively. They can get different hard-registers. The reload pass works on pseudo registers basis and there is no way to say the reload that pseudo could be in different registers and it is even more difficult to say in what places of the code the pseudo should have particular hard-registers. So in this case IRA has to create and use a new pseudo-register inside the region and adds code to move allocno values on the region's borders. This is done by the code in this file. The code makes top-down traversal of the regions and generate new pseudos and the move code on the region borders. In some complicated cases IRA can create a new pseudo used temporarily to move allocno values when a swap of values stored in two hard-registers is needed (e.g. two allocnos representing different pseudos outside region got respectively hard registers 1 and 2 and the corresponding allocnos inside the region got respectively hard registers 2 and 1). At this stage, the new pseudo is marked as spilled. IRA still creates the pseudo-register and the moves on the region borders even when the both corresponding allocnos were assigned to the same hard-register. It is done because, if the reload pass for some reason spills a pseudo-register representing the original pseudo outside or inside the region, the effect will be smaller because another pseudo will still be in the hard-register. In most cases, this is better then spilling the original pseudo in its whole live-range. If reload does not change the allocation for the two pseudo-registers, the trivial move will be removed by post-reload optimizations. IRA does not generate a new pseudo and moves for the allocno values if the both allocnos representing an original pseudo inside and outside region assigned to the same hard register when the register pressure in the region for the corresponding pressure class is less than number of available hard registers for given pressure class. IRA also does some optimizations to remove redundant moves which is transformed into stores by the reload pass on CFG edges representing exits from the region. IRA tries to reduce duplication of code generated on CFG edges which are enters and exits to/from regions by moving some code to the edge sources or destinations when it is possible.
Data used to emit live range split insns and to flattening IR.
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Bitmap of allocnos local for the current loop.
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Max regno before renaming some pseudo-registers. For example, the same pseudo-register can be renamed in a loop if its allocation is different outside the loop.
Definition of vector of moves.
This vec contains moves sorted topologically (depth-first) on their dependency graph.
Pointers to data allocated for allocnos being created during emitting. Usually there are quite few such allocnos because they are created only for resolving loop in register shuffling.
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This bitmap contains regnos of allocnos which were renamed locally because the allocnos correspond to disjoint live ranges in loops with a common parent.
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This bitmap is used to find that we need to generate and to use a new pseudo-register when processing allocnos with the same original regno.
1.8.1.1