6772a17acc
This pass detects induction variables and calculates the trip count of loops to be used for loop unrolling. V2: Rebase, adapt to removal of function overloads V3: (Timothy Arceri) - don't try to find trip count if loop terminator conditional is a phi - fix trip count for do-while loops - replace conditional type != alu assert with return - disable unrolling of loops with continues - multiple fixes to memory allocation, stop leaking and don't destroy structs we want to use for unrolling. - fix iteration count bugs when induction var not on RHS of condition - add FIXME for && conditions - calculate trip count for unsigned induction/limit vars V4: (Timothy Arceri) - count instructions in a loop - set the limiting_terminator even if we can't find the trip count for all terminators. This is needed for complex unrolling where we handle 2 terminators and the trip count is unknown for one of them. - restruct structs so we don't keep information not required after analysis and remove dead fields. - force unrolling in some cases as per the rules in the GLSL IR pass V5: (Timothy Arceri) - fix metadata mask value 0x10 vs 0x16 V6: (Timothy Arceri) - merge loop_variable and nir_loop_variable structs and lists suggested by Jason - remove induction var hash table and store pointer to induction information in the loop_variable suggested by Jason. - use lowercase list_addtail() suggested by Jason. - tidy up init_loop_block() as per Jasons suggestions. - replace switch with nir_op_infos[alu->op].num_inputs == 2 in is_var_basic_induction_var() as suggested by Jason. - use nir_block_last_instr() in and rename foreach_cf_node_ex_loop() as suggested by Jason. - fix else check for is_trivial_loop_terminator() as per Connors suggetions. - simplify offset for induction valiables incremented before the exit conditions is checked. - replace nir_op_isub check with assert() as it should have been lowered away. V7: (Timothy Arceri) - use rzalloc() on nir_loop struct creation. Worked previously because ralloc() was broken and always zeroed the struct. - fix cf_node_find_loop_jumps() to find jumps when loops contain nested if statements. Code is tidier as a result. V8: (Timothy Arceri) - move is_trivial_loop_terminator() to nir.h so we can use it to assert is the loop unroll pass - fix analysis to not bail when looking for terminator when the break is in the else rather then the if - added new loop terminator fields: break_block, continue_from_block and continue_from_then so we don't have to gather these when doing unrolling. - get correct array length when forcing unrolling of variables indexed arrays that are the same size as the iteration count - add support for induction variables of type float - update trival loop terminator check to allow an if containing instructions as long as both branches contain only a single block. V9: (Timothy) - bunch of tidy ups and simplifications suggested by Jason. - rewrote trivial terminator detection, now the only restriction is there must be no nested jumps, anything else goes. - rewrote the iteration test to use nir_eval_const_opcode(). - count instruction properly even when forcing an unroll. - bunch of other tidy ups and simplifications. V10: (Timothy) - some trivial tidy ups suggested by Jason. - conditional fix for break inside continue branch by Jason. Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
93 lines
3.1 KiB
C
93 lines
3.1 KiB
C
/*
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* Copyright © 2016 Intel Corporation
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice (including the next
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* paragraph) shall be included in all copies or substantial portions of the
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* Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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* IN THE SOFTWARE.
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*/
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#pragma once
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#include "nir.h"
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/* Returns true if nir_cf_node contains a jump other than the expected_jump
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* parameter.
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*/
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static inline bool
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contains_other_jump(nir_cf_node *node, nir_instr *expected_jump)
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{
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switch (node->type) {
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case nir_cf_node_block: {
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nir_instr *lst_instr = nir_block_last_instr(nir_cf_node_as_block(node));
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/* dead_cf should have eliminated any instruction after the first break
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*/
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nir_foreach_instr(instr, nir_cf_node_as_block(node))
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assert(instr->type != nir_instr_type_jump || instr == lst_instr);
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if (lst_instr && lst_instr->type == nir_instr_type_jump &&
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lst_instr != expected_jump)
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return true;
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else
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return false;
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}
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case nir_cf_node_if: {
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nir_if *if_stmt = nir_cf_node_as_if(node);
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foreach_list_typed_safe(nir_cf_node, node, node, &if_stmt->then_list) {
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if (contains_other_jump(node, expected_jump))
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return true;
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}
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foreach_list_typed_safe(nir_cf_node, node, node, &if_stmt->else_list) {
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if (contains_other_jump(node, expected_jump))
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return true;
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}
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return false;
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}
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case nir_cf_node_loop:
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return true;
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default:
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unreachable("Unhandled cf node type");
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}
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}
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/* Here we define a trivial if as containing only a single break that must be
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* located at the end of either the then or else branch of the top level if,
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* there must be no other breaks or any other type of jump. Or we pass NULL
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* to break_block the if must contains no jumps at all.
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*/
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static inline bool
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nir_is_trivial_loop_if(nir_if *nif, nir_block *break_block)
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{
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nir_instr *last_instr = NULL;
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if (break_block) {
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last_instr = nir_block_last_instr(break_block);
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assert(last_instr && last_instr->type == nir_instr_type_jump &&
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nir_instr_as_jump(last_instr)->type == nir_jump_break);
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}
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if (contains_other_jump(&nif->cf_node, last_instr))
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return false;
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return true;
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}
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