| /* Code to analyze doloop loops in order for targets to perform late |
| optimizations converting doloops to other forms of hardware loops. |
| Copyright (C) 2011-2018 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 |
| <http://www.gnu.org/licenses/>. */ |
| |
| #ifndef GCC_HW_DOLOOP_H |
| #define GCC_HW_DOLOOP_H |
| |
| /* We need to keep a vector of loops */ |
| typedef struct hwloop_info_d *hwloop_info; |
| |
| /* Information about a loop we have found (or are in the process of |
| finding). */ |
| struct GTY (()) hwloop_info_d |
| { |
| /* loop number, for dumps */ |
| int loop_no; |
| |
| /* Next loop in the graph. */ |
| hwloop_info next; |
| |
| /* Vector of blocks only within the loop, including those within |
| inner loops. */ |
| vec<basic_block> blocks; |
| |
| /* Same information in a bitmap. */ |
| bitmap block_bitmap; |
| |
| /* Vector of inner loops within this loop. Includes loops of every |
| nesting level. */ |
| vec<hwloop_info> loops; |
| |
| /* All edges that jump into the loop. */ |
| vec<edge, va_gc> *incoming; |
| |
| /* The ports currently using this infrastructure can typically |
| handle two cases: all incoming edges have the same destination |
| block, or all incoming edges have the same source block. These |
| two members are set to the common source or destination we found, |
| or NULL if different blocks were found. If both are NULL the |
| loop can't be optimized. */ |
| basic_block incoming_src; |
| basic_block incoming_dest; |
| |
| /* First block in the loop. This is the one branched to by the loop_end |
| insn. */ |
| basic_block head; |
| |
| /* Last block in the loop (the one with the loop_end insn). */ |
| basic_block tail; |
| |
| /* The successor block of the loop. This is the one the loop_end insn |
| falls into. */ |
| basic_block successor; |
| |
| /* The last instruction in the tail. */ |
| rtx_insn *last_insn; |
| |
| /* The loop_end insn. */ |
| rtx_insn *loop_end; |
| |
| /* The iteration register. */ |
| rtx iter_reg; |
| |
| /* The new label placed at the beginning of the loop. */ |
| rtx_insn *start_label; |
| |
| /* The new label placed at the end of the loop. */ |
| rtx end_label; |
| |
| /* The length of the loop. */ |
| int length; |
| |
| /* The nesting depth of the loop. Innermost loops are given a depth |
| of 1. Only successfully optimized doloops are counted; if an inner |
| loop was marked as bad, it does not increase the depth of its parent |
| loop. |
| This value is valid when the target's optimize function is called. */ |
| int depth; |
| |
| /* True if we can't optimize this loop. */ |
| bool bad; |
| |
| /* True if we have visited this loop during the optimization phase. */ |
| bool visited; |
| |
| /* The following values are collected before calling the target's optimize |
| function and are not valid earlier. */ |
| |
| /* Record information about control flow: whether the loop has calls |
| or asm statements, whether it has edges that jump out of the loop, |
| or edges that jump within the loop. */ |
| bool has_call; |
| bool has_asm; |
| bool jumps_within; |
| bool jumps_outof; |
| |
| /* True if there is an instruction other than the doloop_end which uses the |
| iteration register. */ |
| bool iter_reg_used; |
| /* True if the iteration register lives past the doloop instruction. */ |
| bool iter_reg_used_outside; |
| |
| /* Hard registers set at any point in the loop, except for the loop counter |
| register's set in the doloop_end instruction. */ |
| HARD_REG_SET regs_set_in_loop; |
| }; |
| |
| /* A set of hooks to be defined by a target that wants to use the reorg_loops |
| functionality. |
| |
| reorg_loops is intended to handle cases where special hardware loop |
| setup instructions are required before the loop, for example to set |
| up loop counter registers that are not exposed to the register |
| allocator, or to inform the hardware about loop bounds. |
| |
| reorg_loops performs analysis to discover loop_end patterns created |
| by the earlier loop-doloop pass, and sets up a hwloop_info |
| structure for each such insn it finds. It then tries to discover |
| the basic blocks containing the loop by tracking the lifetime of |
| the iteration register. |
| |
| If a valid loop can't be found, the FAIL function is called; |
| otherwise the OPT function is called for each loop, visiting |
| innermost loops first and ascending. */ |
| struct hw_doloop_hooks |
| { |
| /* Examine INSN. If it is a suitable doloop_end pattern, return the |
| iteration register, which should be a single hard register. |
| Otherwise, return NULL_RTX. */ |
| rtx (*end_pattern_reg) (rtx_insn *insn); |
| /* Optimize LOOP. The target should perform any additional analysis |
| (e.g. checking that the loop isn't too long), and then perform |
| its transformations. Return true if successful, false if the |
| loop should be marked bad. If it returns false, the FAIL |
| function is called. */ |
| bool (*opt) (hwloop_info loop); |
| /* Handle a loop that was marked bad for any reason. This could be |
| used to split the doloop_end pattern. */ |
| void (*fail) (hwloop_info loop); |
| }; |
| |
| extern void reorg_loops (bool, struct hw_doloop_hooks *); |
| |
| #endif /* GCC_HW_DOLOOP_H */ |