+++ /dev/null
-/* Detection of Static Control Parts (SCoP) for Graphite.
- Copyright (C) 2009-2015 Free Software Foundation, Inc.
- Contributed by Sebastian Pop <sebastian.pop@amd.com> and
- Tobias Grosser <grosser@fim.uni-passau.de>.
-
-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/>. */
-
-#include "config.h"
-
-#ifdef HAVE_isl
-/* Workaround for GMP 5.1.3 bug, see PR56019. */
-#include <stddef.h>
-
-#include <isl/constraint.h>
-#include <isl/set.h>
-#include <isl/map.h>
-#include <isl/union_map.h>
-
-#include "system.h"
-#include "coretypes.h"
-#include "backend.h"
-#include "cfghooks.h"
-#include "tree.h"
-#include "gimple.h"
-#include "ssa.h"
-#include "fold-const.h"
-#include "gimple-iterator.h"
-#include "tree-ssa-loop-manip.h"
-#include "tree-ssa-loop-niter.h"
-#include "tree-ssa-loop.h"
-#include "tree-into-ssa.h"
-#include "tree-ssa.h"
-#include "cfgloop.h"
-#include "tree-data-ref.h"
-#include "tree-scalar-evolution.h"
-#include "tree-pass.h"
-#include "graphite-poly.h"
-#include "tree-ssa-propagate.h"
-#include "graphite-scop-detection.h"
-#include "gimple-pretty-print.h"
-
-/* Forward declarations. */
-static void make_close_phi_nodes_unique (basic_block);
-
-/* The type of the analyzed basic block. */
-
-enum gbb_type {
- GBB_UNKNOWN,
- GBB_LOOP_SING_EXIT_HEADER,
- GBB_LOOP_MULT_EXIT_HEADER,
- GBB_LOOP_EXIT,
- GBB_COND_HEADER,
- GBB_SIMPLE,
- GBB_LAST
-};
-
-/* Detect the type of BB. Loop headers are only marked, if they are
- new. This means their loop_father is different to LAST_LOOP.
- Otherwise they are treated like any other bb and their type can be
- any other type. */
-
-static gbb_type
-get_bb_type (basic_block bb, struct loop *last_loop)
-{
- vec<basic_block> dom;
- int nb_dom;
- struct loop *loop = bb->loop_father;
-
- /* Check, if we entry into a new loop. */
- if (loop != last_loop)
- {
- if (single_exit (loop) != NULL)
- return GBB_LOOP_SING_EXIT_HEADER;
- else if (loop->num != 0)
- return GBB_LOOP_MULT_EXIT_HEADER;
- else
- return GBB_COND_HEADER;
- }
-
- dom = get_dominated_by (CDI_DOMINATORS, bb);
- nb_dom = dom.length ();
- dom.release ();
-
- if (nb_dom == 0)
- return GBB_LAST;
-
- if (nb_dom == 1 && single_succ_p (bb))
- return GBB_SIMPLE;
-
- return GBB_COND_HEADER;
-}
-
-/* A SCoP detection region, defined using bbs as borders.
-
- All control flow touching this region, comes in passing basic_block
- ENTRY and leaves passing basic_block EXIT. By using bbs instead of
- edges for the borders we are able to represent also regions that do
- not have a single entry or exit edge.
-
- But as they have a single entry basic_block and a single exit
- basic_block, we are able to generate for every sd_region a single
- entry and exit edge.
-
- 1 2
- \ /
- 3 <- entry
- |
- 4
- / \ This region contains: {3, 4, 5, 6, 7, 8}
- 5 6
- | |
- 7 8
- \ /
- 9 <- exit */
-
-
-struct sd_region
-{
- /* The entry bb dominates all bbs in the sd_region. It is part of
- the region. */
- basic_block entry;
-
- /* The exit bb postdominates all bbs in the sd_region, but is not
- part of the region. */
- basic_block exit;
-};
-
-
-
-/* Moves the scops from SOURCE to TARGET and clean up SOURCE. */
-
-static void
-move_sd_regions (vec<sd_region> *source, vec<sd_region> *target)
-{
- sd_region *s;
- int i;
-
- FOR_EACH_VEC_ELT (*source, i, s)
- target->safe_push (*s);
-
- source->release ();
-}
-
-/* Something like "n * m" is not allowed. */
-
-static bool
-graphite_can_represent_init (tree e)
-{
- switch (TREE_CODE (e))
- {
- case POLYNOMIAL_CHREC:
- return graphite_can_represent_init (CHREC_LEFT (e))
- && graphite_can_represent_init (CHREC_RIGHT (e));
-
- case MULT_EXPR:
- if (chrec_contains_symbols (TREE_OPERAND (e, 0)))
- return graphite_can_represent_init (TREE_OPERAND (e, 0))
- && tree_fits_shwi_p (TREE_OPERAND (e, 1));
- else
- return graphite_can_represent_init (TREE_OPERAND (e, 1))
- && tree_fits_shwi_p (TREE_OPERAND (e, 0));
-
- case PLUS_EXPR:
- case POINTER_PLUS_EXPR:
- case MINUS_EXPR:
- return graphite_can_represent_init (TREE_OPERAND (e, 0))
- && graphite_can_represent_init (TREE_OPERAND (e, 1));
-
- case NEGATE_EXPR:
- case BIT_NOT_EXPR:
- CASE_CONVERT:
- case NON_LVALUE_EXPR:
- return graphite_can_represent_init (TREE_OPERAND (e, 0));
-
- default:
- break;
- }
-
- return true;
-}
-
-/* Return true when SCEV can be represented in the polyhedral model.
-
- An expression can be represented, if it can be expressed as an
- affine expression. For loops (i, j) and parameters (m, n) all
- affine expressions are of the form:
-
- x1 * i + x2 * j + x3 * m + x4 * n + x5 * 1 where x1..x5 element of Z
-
- 1 i + 20 j + (-2) m + 25
-
- Something like "i * n" or "n * m" is not allowed. */
-
-static bool
-graphite_can_represent_scev (tree scev)
-{
- if (chrec_contains_undetermined (scev))
- return false;
-
- /* We disable the handling of pointer types, because it’s currently not
- supported by Graphite with the ISL AST generator. SSA_NAME nodes are
- the only nodes, which are disabled in case they are pointers to object
- types, but this can be changed. */
-
- if (POINTER_TYPE_P (TREE_TYPE (scev)) && TREE_CODE (scev) == SSA_NAME)
- return false;
-
- switch (TREE_CODE (scev))
- {
- case NEGATE_EXPR:
- case BIT_NOT_EXPR:
- CASE_CONVERT:
- case NON_LVALUE_EXPR:
- return graphite_can_represent_scev (TREE_OPERAND (scev, 0));
-
- case PLUS_EXPR:
- case POINTER_PLUS_EXPR:
- case MINUS_EXPR:
- return graphite_can_represent_scev (TREE_OPERAND (scev, 0))
- && graphite_can_represent_scev (TREE_OPERAND (scev, 1));
-
- case MULT_EXPR:
- return !CONVERT_EXPR_CODE_P (TREE_CODE (TREE_OPERAND (scev, 0)))
- && !CONVERT_EXPR_CODE_P (TREE_CODE (TREE_OPERAND (scev, 1)))
- && !(chrec_contains_symbols (TREE_OPERAND (scev, 0))
- && chrec_contains_symbols (TREE_OPERAND (scev, 1)))
- && graphite_can_represent_init (scev)
- && graphite_can_represent_scev (TREE_OPERAND (scev, 0))
- && graphite_can_represent_scev (TREE_OPERAND (scev, 1));
-
- case POLYNOMIAL_CHREC:
- /* Check for constant strides. With a non constant stride of
- 'n' we would have a value of 'iv * n'. Also check that the
- initial value can represented: for example 'n * m' cannot be
- represented. */
- if (!evolution_function_right_is_integer_cst (scev)
- || !graphite_can_represent_init (scev))
- return false;
- return graphite_can_represent_scev (CHREC_LEFT (scev));
-
- default:
- break;
- }
-
- /* Only affine functions can be represented. */
- if (tree_contains_chrecs (scev, NULL)
- || !scev_is_linear_expression (scev))
- return false;
-
- return true;
-}
-
-
-/* Return true when EXPR can be represented in the polyhedral model.
-
- This means an expression can be represented, if it is linear with
- respect to the loops and the strides are non parametric.
- LOOP is the place where the expr will be evaluated. SCOP_ENTRY defines the
- entry of the region we analyse. */
-
-static bool
-graphite_can_represent_expr (basic_block scop_entry, loop_p loop,
- tree expr)
-{
- tree scev = analyze_scalar_evolution (loop, expr);
-
- scev = instantiate_scev (scop_entry, loop, scev);
-
- return graphite_can_represent_scev (scev);
-}
-
-/* Return true if the data references of STMT can be represented by
- Graphite. */
-
-static bool
-stmt_has_simple_data_refs_p (loop_p outermost_loop ATTRIBUTE_UNUSED,
- gimple *stmt)
-{
- data_reference_p dr;
- int j;
- bool res = true;
- vec<data_reference_p> drs = vNULL;
- loop_p outer;
-
- for (outer = loop_containing_stmt (stmt); outer; outer = loop_outer (outer))
- {
- graphite_find_data_references_in_stmt (outer,
- loop_containing_stmt (stmt),
- stmt, &drs);
-
- FOR_EACH_VEC_ELT (drs, j, dr)
- {
- int nb_subscripts = DR_NUM_DIMENSIONS (dr);
- tree ref = DR_REF (dr);
-
- for (int i = nb_subscripts - 1; i >= 0; i--)
- {
- if (!graphite_can_represent_scev (DR_ACCESS_FN (dr, i))
- || (TREE_CODE (ref) != ARRAY_REF
- && TREE_CODE (ref) != MEM_REF
- && TREE_CODE (ref) != COMPONENT_REF))
- {
- free_data_refs (drs);
- return false;
- }
-
- ref = TREE_OPERAND (ref, 0);
- }
- }
-
- free_data_refs (drs);
- drs.create (0);
- }
-
- free_data_refs (drs);
- return res;
-}
-
-/* Return true only when STMT is simple enough for being handled by
- Graphite. This depends on SCOP_ENTRY, as the parameters are
- initialized relatively to this basic block, the linear functions
- are initialized to OUTERMOST_LOOP and BB is the place where we try
- to evaluate the STMT. */
-
-static bool
-stmt_simple_for_scop_p (basic_block scop_entry, loop_p outermost_loop,
- gimple *stmt, basic_block bb)
-{
- loop_p loop = bb->loop_father;
-
- gcc_assert (scop_entry);
-
- /* GIMPLE_ASM and GIMPLE_CALL may embed arbitrary side effects.
- Calls have side-effects, except those to const or pure
- functions. */
- if (gimple_has_volatile_ops (stmt)
- || (gimple_code (stmt) == GIMPLE_CALL
- && !(gimple_call_flags (stmt) & (ECF_CONST | ECF_PURE)))
- || (gimple_code (stmt) == GIMPLE_ASM))
- {
- if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file, "[scop-detection-fail] ");
- fprintf (dump_file, "Graphite cannot handle this stmt:\n");
- print_gimple_stmt (dump_file, stmt, 0, TDF_VOPS|TDF_MEMSYMS);
- }
-
- return false;
- }
-
- if (is_gimple_debug (stmt))
- return true;
-
- if (!stmt_has_simple_data_refs_p (outermost_loop, stmt))
- {
- if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file, "[scop-detection-fail] ");
- fprintf (dump_file, "Graphite cannot handle data-refs in stmt:\n");
- print_gimple_stmt (dump_file, stmt, 0, TDF_VOPS|TDF_MEMSYMS);
- }
-
- return false;
- }
-
- switch (gimple_code (stmt))
- {
- case GIMPLE_LABEL:
- return true;
-
- case GIMPLE_COND:
- {
- /* We can handle all binary comparisons. Inequalities are
- also supported as they can be represented with union of
- polyhedra. */
- enum tree_code code = gimple_cond_code (stmt);
- if (!(code == LT_EXPR
- || code == GT_EXPR
- || code == LE_EXPR
- || code == GE_EXPR
- || code == EQ_EXPR
- || code == NE_EXPR))
- {
- if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file, "[scop-detection-fail] ");
- fprintf (dump_file, "Graphite cannot handle cond stmt:\n");
- print_gimple_stmt (dump_file, stmt, 0, TDF_VOPS|TDF_MEMSYMS);
- }
-
- return false;
- }
-
- for (unsigned i = 0; i < 2; ++i)
- {
- tree op = gimple_op (stmt, i);
- if (!graphite_can_represent_expr (scop_entry, loop, op)
- /* We can only constrain on integer type. */
- || (TREE_CODE (TREE_TYPE (op)) != INTEGER_TYPE))
- {
- if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file, "[scop-detection-fail] ");
- fprintf (dump_file, "Graphite cannot represent stmt:\n");
- print_gimple_stmt (dump_file, stmt, 0, TDF_VOPS|TDF_MEMSYMS);
- }
-
- return false;
- }
- }
-
- return true;
- }
-
- case GIMPLE_ASSIGN:
- case GIMPLE_CALL:
- return true;
-
- default:
- /* These nodes cut a new scope. */
- if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file, "[scop-detection-fail] ");
- fprintf (dump_file, "Gimple stmt not handled in Graphite:\n");
- print_gimple_stmt (dump_file, stmt, 0, TDF_VOPS|TDF_MEMSYMS);
- }
- return false;
- }
-
- return false;
-}
-
-/* Returns the statement of BB that contains a harmful operation: that
- can be a function call with side effects, the induction variables
- are not linear with respect to SCOP_ENTRY, etc. The current open
- scop should end before this statement. The evaluation is limited using
- OUTERMOST_LOOP as outermost loop that may change. */
-
-static gimple *
-harmful_stmt_in_bb (basic_block scop_entry, loop_p outer_loop, basic_block bb)
-{
- gimple_stmt_iterator gsi;
-
- for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
- if (!stmt_simple_for_scop_p (scop_entry, outer_loop, gsi_stmt (gsi), bb))
- return gsi_stmt (gsi);
-
- return NULL;
-}
-
-/* Return true if LOOP can be represented in the polyhedral
- representation. This is evaluated taking SCOP_ENTRY and
- OUTERMOST_LOOP in mind. */
-
-static bool
-graphite_can_represent_loop (basic_block scop_entry, loop_p loop)
-{
- tree niter;
- struct tree_niter_desc niter_desc;
-
- if (!loop_nest_has_data_refs (loop))
- {
- if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file, "[scop-detection-fail] ");
- fprintf (dump_file, "Loop %d does not have any data reference.\n",
- loop->num);
- }
- return false;
- }
-
- /* FIXME: For the moment, graphite cannot be used on loops that
- iterate using induction variables that wrap. */
-
- return number_of_iterations_exit (loop, single_exit (loop), &niter_desc, false)
- && niter_desc.control.no_overflow
- && (niter = number_of_latch_executions (loop))
- && !chrec_contains_undetermined (niter)
- && graphite_can_represent_expr (scop_entry, loop, niter);
-}
-
-/* Store information needed by scopdet_* functions. */
-
-struct scopdet_info
-{
- /* Exit of the open scop would stop if the current BB is harmful. */
- basic_block exit;
-
- /* Where the next scop would start if the current BB is harmful. */
- basic_block next;
-
- /* The bb or one of its children contains open loop exits. That means
- loop exit nodes that are not surrounded by a loop dominated by bb. */
- bool exits;
-
- /* The bb or one of its children contains only structures we can handle. */
- bool difficult;
-};
-
-static struct scopdet_info build_scops_1 (basic_block, loop_p,
- vec<sd_region> *, loop_p);
-
-/* Calculates BB infos. If bb is difficult we add valid SCoPs dominated by BB
- to SCOPS. TYPE is the gbb_type of BB. */
-
-static struct scopdet_info
-scopdet_basic_block_info (basic_block bb, loop_p outermost_loop,
- vec<sd_region> *scops, gbb_type type)
-{
- loop_p loop = bb->loop_father;
- struct scopdet_info result;
- gimple *stmt;
-
- /* XXX: ENTRY_BLOCK_PTR could be optimized in later steps. */
- basic_block entry_block = ENTRY_BLOCK_PTR_FOR_FN (cfun);
- stmt = harmful_stmt_in_bb (entry_block, outermost_loop, bb);
- result.difficult = (stmt != NULL);
- result.exit = NULL;
-
- switch (type)
- {
- case GBB_LAST:
- result.next = NULL;
- result.exits = false;
-
- /* Mark bbs terminating a SESE region difficult, if they start
- a condition or if the block it exits to cannot be split
- with make_forwarder_block. */
- if (!single_succ_p (bb)
- || bb_has_abnormal_pred (single_succ (bb)))
- {
- if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file, "[scop-detection-fail] ");
- fprintf (dump_file, "BB %d cannot be part of a scop.\n",
- bb->index);
- }
-
- result.difficult = true;
- }
- else
- result.exit = single_succ (bb);
-
- break;
-
- case GBB_SIMPLE:
- result.next = single_succ (bb);
- result.exits = false;
- result.exit = single_succ (bb);
- break;
-
- case GBB_LOOP_SING_EXIT_HEADER:
- {
- auto_vec<sd_region, 3> regions;
- struct scopdet_info sinfo;
- edge exit_e = single_exit (loop);
-
- sinfo = build_scops_1 (bb, outermost_loop, ®ions, loop);
-
- if (!graphite_can_represent_loop (entry_block, loop))
- {
- if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file, "[scop-detection-fail] ");
- fprintf (dump_file, "Graphite cannot represent loop %d.\n",
- loop->num);
- }
- result.difficult = true;
- }
-
- result.difficult |= sinfo.difficult;
-
- /* Try again with another loop level. */
- if (result.difficult
- && loop_depth (outermost_loop) + 1 == loop_depth (loop))
- {
- outermost_loop = loop;
-
- regions.release ();
- regions.create (3);
-
- sinfo = scopdet_basic_block_info (bb, outermost_loop, scops, type);
-
- result = sinfo;
- result.difficult = true;
-
- if (sinfo.difficult)
- move_sd_regions (®ions, scops);
- else
- {
- sd_region open_scop;
- open_scop.entry = bb;
- open_scop.exit = exit_e->dest;
- scops->safe_push (open_scop);
- regions.release ();
- }
- }
- else
- {
- result.exit = exit_e->dest;
- result.next = exit_e->dest;
-
- /* If we do not dominate result.next, remove it. It's either
- the exit block, or another bb dominates it and will
- call the scop detection for this bb. */
- if (!dominated_by_p (CDI_DOMINATORS, result.next, bb))
- result.next = NULL;
-
- if (exit_e->src->loop_father != loop)
- result.next = NULL;
-
- result.exits = false;
-
- if (result.difficult)
- move_sd_regions (®ions, scops);
- else
- regions.release ();
- }
-
- break;
- }
-
- case GBB_LOOP_MULT_EXIT_HEADER:
- {
- /* XXX: For now we just do not join loops with multiple exits. If the
- exits lead to the same bb it may be possible to join the loop. */
- auto_vec<sd_region, 3> regions;
- vec<edge> exits = get_loop_exit_edges (loop);
- edge e;
- int i;
- build_scops_1 (bb, loop, ®ions, loop);
-
- /* Scan the code dominated by this loop. This means all bbs, that are
- are dominated by a bb in this loop, but are not part of this loop.
-
- The easiest case:
- - The loop exit destination is dominated by the exit sources.
-
- TODO: We miss here the more complex cases:
- - The exit destinations are dominated by another bb inside
- the loop.
- - The loop dominates bbs, that are not exit destinations. */
- FOR_EACH_VEC_ELT (exits, i, e)
- if (e->src->loop_father == loop
- && dominated_by_p (CDI_DOMINATORS, e->dest, e->src))
- {
- if (loop_outer (outermost_loop))
- outermost_loop = loop_outer (outermost_loop);
-
- /* Pass loop_outer to recognize e->dest as loop header in
- build_scops_1. */
- if (e->dest->loop_father->header == e->dest)
- build_scops_1 (e->dest, outermost_loop, ®ions,
- loop_outer (e->dest->loop_father));
- else
- build_scops_1 (e->dest, outermost_loop, ®ions,
- e->dest->loop_father);
- }
-
- result.next = NULL;
- result.exit = NULL;
- result.difficult = true;
- result.exits = false;
- move_sd_regions (®ions, scops);
- exits.release ();
- break;
- }
- case GBB_COND_HEADER:
- {
- auto_vec<sd_region, 3> regions;
- struct scopdet_info sinfo;
- vec<basic_block> dominated;
- int i;
- basic_block dom_bb;
- basic_block last_exit = NULL;
- edge e;
- result.exits = false;
-
- /* First check the successors of BB, and check if it is
- possible to join the different branches. */
- FOR_EACH_VEC_SAFE_ELT (bb->succs, i, e)
- {
- /* Ignore loop exits. They will be handled after the loop
- body. */
- if (loop_exits_to_bb_p (loop, e->dest))
- {
- result.exits = true;
- continue;
- }
-
- /* Do not follow edges that lead to the end of the
- conditions block. For example, in
-
- | 0
- | /|\
- | 1 2 |
- | | | |
- | 3 4 |
- | \|/
- | 6
-
- the edge from 0 => 6. Only check if all paths lead to
- the same node 6. */
-
- if (!single_pred_p (e->dest))
- {
- /* Check, if edge leads directly to the end of this
- condition. */
- if (!last_exit)
- last_exit = e->dest;
-
- if (e->dest != last_exit)
- result.difficult = true;
-
- continue;
- }
-
- if (!dominated_by_p (CDI_DOMINATORS, e->dest, bb))
- {
- result.difficult = true;
- continue;
- }
-
- sinfo = build_scops_1 (e->dest, outermost_loop, ®ions, loop);
-
- result.exits |= sinfo.exits;
- result.difficult |= sinfo.difficult;
-
- /* Checks, if all branches end at the same point.
- If that is true, the condition stays joinable.
- Have a look at the example above. */
- if (sinfo.exit)
- {
- if (!last_exit)
- last_exit = sinfo.exit;
-
- if (sinfo.exit != last_exit)
- result.difficult = true;
- }
- else
- result.difficult = true;
- }
-
- if (!last_exit)
- result.difficult = true;
-
- /* Join the branches of the condition if possible. */
- if (!result.exits && !result.difficult)
- {
- /* Only return a next pointer if we dominate this pointer.
- Otherwise it will be handled by the bb dominating it. */
- if (dominated_by_p (CDI_DOMINATORS, last_exit, bb)
- && last_exit != bb)
- result.next = last_exit;
- else
- result.next = NULL;
-
- result.exit = last_exit;
-
- regions.release ();
- break;
- }
-
- /* Scan remaining bbs dominated by BB. */
- dominated = get_dominated_by (CDI_DOMINATORS, bb);
-
- FOR_EACH_VEC_ELT (dominated, i, dom_bb)
- {
- /* Ignore loop exits: they will be handled after the loop body. */
- if (loop_depth (find_common_loop (loop, dom_bb->loop_father))
- < loop_depth (loop))
- {
- result.exits = true;
- continue;
- }
-
- /* Ignore the bbs processed above. */
- if (single_pred_p (dom_bb) && single_pred (dom_bb) == bb)
- continue;
-
- if (loop_depth (loop) > loop_depth (dom_bb->loop_father))
- sinfo = build_scops_1 (dom_bb, outermost_loop, ®ions,
- loop_outer (loop));
- else
- sinfo = build_scops_1 (dom_bb, outermost_loop, ®ions, loop);
-
- result.exits |= sinfo.exits;
- result.difficult = true;
- result.exit = NULL;
- }
-
- dominated.release ();
-
- result.next = NULL;
- move_sd_regions (®ions, scops);
-
- break;
- }
-
- default:
- gcc_unreachable ();
- }
-
- return result;
-}
-
-/* Starting from CURRENT we walk the dominance tree and add new sd_regions to
- SCOPS. The analyse if a sd_region can be handled is based on the value
- of OUTERMOST_LOOP. Only loops inside OUTERMOST loops may change. LOOP
- is the loop in which CURRENT is handled.
-
- TODO: These functions got a little bit big. They definitely should be cleaned
- up. */
-
-static struct scopdet_info
-build_scops_1 (basic_block current, loop_p outermost_loop,
- vec<sd_region> *scops, loop_p loop)
-{
- bool in_scop = false;
- sd_region open_scop;
- struct scopdet_info sinfo;
-
- /* Initialize result. */
- struct scopdet_info result;
- result.exits = false;
- result.difficult = false;
- result.next = NULL;
- result.exit = NULL;
- open_scop.entry = NULL;
- open_scop.exit = NULL;
- sinfo.exit = NULL;
-
- /* Loop over the dominance tree. If we meet a difficult bb, close
- the current SCoP. Loop and condition header start a new layer,
- and can only be added if all bbs in deeper layers are simple. */
- while (current != NULL)
- {
- sinfo = scopdet_basic_block_info (current, outermost_loop, scops,
- get_bb_type (current, loop));
-
- if (!in_scop && !(sinfo.exits || sinfo.difficult))
- {
- open_scop.entry = current;
- open_scop.exit = NULL;
- in_scop = true;
- }
- else if (in_scop && (sinfo.exits || sinfo.difficult))
- {
- open_scop.exit = current;
- scops->safe_push (open_scop);
- in_scop = false;
- }
-
- result.difficult |= sinfo.difficult;
- result.exits |= sinfo.exits;
-
- current = sinfo.next;
- }
-
- /* Try to close open_scop, if we are still in an open SCoP. */
- if (in_scop)
- {
- open_scop.exit = sinfo.exit;
- gcc_assert (open_scop.exit);
- if (open_scop.entry != open_scop.exit)
- scops->safe_push (open_scop);
- else
- {
- sinfo.difficult = true;
- sinfo.exits = false;
- sinfo.exit = NULL;
- }
- }
-
- result.exit = sinfo.exit;
- return result;
-}
-
-/* Checks if a bb is contained in REGION. */
-
-static bool
-bb_in_sd_region (basic_block bb, sd_region *region)
-{
- return bb_in_region (bb, region->entry, region->exit);
-}
-
-/* Returns the single entry edge of REGION, if it does not exits NULL. */
-
-static edge
-find_single_entry_edge (sd_region *region)
-{
- edge e;
- edge_iterator ei;
- edge entry = NULL;
-
- FOR_EACH_EDGE (e, ei, region->entry->preds)
- if (!bb_in_sd_region (e->src, region))
- {
- if (entry)
- {
- entry = NULL;
- break;
- }
-
- else
- entry = e;
- }
-
- return entry;
-}
-
-/* Returns the single exit edge of REGION, if it does not exits NULL. */
-
-static edge
-find_single_exit_edge (sd_region *region)
-{
- edge e;
- edge_iterator ei;
- edge exit = NULL;
-
- FOR_EACH_EDGE (e, ei, region->exit->preds)
- if (bb_in_sd_region (e->src, region))
- {
- if (exit)
- {
- exit = NULL;
- break;
- }
-
- else
- exit = e;
- }
-
- return exit;
-}
-
-/* Create a single entry edge for REGION. */
-
-static void
-create_single_entry_edge (sd_region *region)
-{
- if (find_single_entry_edge (region))
- return;
-
- /* There are multiple predecessors for bb_3
-
- | 1 2
- | | /
- | |/
- | 3 <- entry
- | |\
- | | |
- | 4 ^
- | | |
- | |/
- | 5
-
- There are two edges (1->3, 2->3), that point from outside into the region,
- and another one (5->3), a loop latch, lead to bb_3.
-
- We split bb_3.
-
- | 1 2
- | | /
- | |/
- |3.0
- | |\ (3.0 -> 3.1) = single entry edge
- |3.1 | <- entry
- | | |
- | | |
- | 4 ^
- | | |
- | |/
- | 5
-
- If the loop is part of the SCoP, we have to redirect the loop latches.
-
- | 1 2
- | | /
- | |/
- |3.0
- | | (3.0 -> 3.1) = entry edge
- |3.1 <- entry
- | |\
- | | |
- | 4 ^
- | | |
- | |/
- | 5 */
-
- if (region->entry->loop_father->header != region->entry
- || dominated_by_p (CDI_DOMINATORS,
- loop_latch_edge (region->entry->loop_father)->src,
- region->exit))
- {
- edge forwarder = split_block_after_labels (region->entry);
- region->entry = forwarder->dest;
- }
- else
- /* This case is never executed, as the loop headers seem always to have a
- single edge pointing from outside into the loop. */
- gcc_unreachable ();
-
- gcc_checking_assert (find_single_entry_edge (region));
-}
-
-/* Check if the sd_region, mentioned in EDGE, has no exit bb. */
-
-static bool
-sd_region_without_exit (edge e)
-{
- sd_region *r = (sd_region *) e->aux;
-
- if (r)
- return r->exit == NULL;
- else
- return false;
-}
-
-/* Create a single exit edge for REGION. */
-
-static void
-create_single_exit_edge (sd_region *region)
-{
- edge e;
- edge_iterator ei;
- edge forwarder = NULL;
- basic_block exit;
-
- /* We create a forwarder bb (5) for all edges leaving this region
- (3->5, 4->5). All other edges leading to the same bb, are moved
- to a new bb (6). If these edges where part of another region (2->5)
- we update the region->exit pointer, of this region.
-
- To identify which edge belongs to which region we depend on the e->aux
- pointer in every edge. It points to the region of the edge or to NULL,
- if the edge is not part of any region.
-
- 1 2 3 4 1->5 no region, 2->5 region->exit = 5,
- \| |/ 3->5 region->exit = NULL, 4->5 region->exit = NULL
- 5 <- exit
-
- changes to
-
- 1 2 3 4 1->6 no region, 2->6 region->exit = 6,
- | | \/ 3->5 no region, 4->5 no region,
- | | 5
- \| / 5->6 region->exit = 6
- 6
-
- Now there is only a single exit edge (5->6). */
- exit = region->exit;
- region->exit = NULL;
- forwarder = make_forwarder_block (exit, &sd_region_without_exit, NULL);
-
- /* Unmark the edges, that are no longer exit edges. */
- FOR_EACH_EDGE (e, ei, forwarder->src->preds)
- if (e->aux)
- e->aux = NULL;
-
- /* Mark the new exit edge. */
- single_succ_edge (forwarder->src)->aux = region;
-
- /* Update the exit bb of all regions, where exit edges lead to
- forwarder->dest. */
- FOR_EACH_EDGE (e, ei, forwarder->dest->preds)
- if (e->aux)
- ((sd_region *) e->aux)->exit = forwarder->dest;
-
- gcc_checking_assert (find_single_exit_edge (region));
-}
-
-/* Unmark the exit edges of all REGIONS.
- See comment in "create_single_exit_edge". */
-
-static void
-unmark_exit_edges (vec<sd_region> regions)
-{
- int i;
- sd_region *s;
- edge e;
- edge_iterator ei;
-
- FOR_EACH_VEC_ELT (regions, i, s)
- FOR_EACH_EDGE (e, ei, s->exit->preds)
- e->aux = NULL;
-}
-
-
-/* Mark the exit edges of all REGIONS.
- See comment in "create_single_exit_edge". */
-
-static void
-mark_exit_edges (vec<sd_region> regions)
-{
- int i;
- sd_region *s;
- edge e;
- edge_iterator ei;
-
- FOR_EACH_VEC_ELT (regions, i, s)
- FOR_EACH_EDGE (e, ei, s->exit->preds)
- if (bb_in_sd_region (e->src, s))
- e->aux = s;
-}
-
-/* Create for all scop regions a single entry and a single exit edge. */
-
-static void
-create_sese_edges (vec<sd_region> regions)
-{
- int i;
- sd_region *s;
-
- FOR_EACH_VEC_ELT (regions, i, s)
- create_single_entry_edge (s);
-
- mark_exit_edges (regions);
-
- FOR_EACH_VEC_ELT (regions, i, s)
- /* Don't handle multiple edges exiting the function. */
- if (!find_single_exit_edge (s)
- && s->exit != EXIT_BLOCK_PTR_FOR_FN (cfun))
- create_single_exit_edge (s);
-
- unmark_exit_edges (regions);
-
- calculate_dominance_info (CDI_DOMINATORS);
- fix_loop_structure (NULL);
-
-#ifdef ENABLE_CHECKING
- verify_loop_structure ();
- verify_ssa (false, true);
-#endif
-}
-
-/* Create graphite SCoPs from an array of scop detection REGIONS. */
-
-static void
-build_graphite_scops (vec<sd_region> regions,
- vec<scop_p> *scops)
-{
- int i;
- sd_region *s;
-
- FOR_EACH_VEC_ELT (regions, i, s)
- {
- edge entry = find_single_entry_edge (s);
- edge exit = find_single_exit_edge (s);
- scop_p scop;
-
- if (!exit)
- continue;
-
- sese sese_reg = new_sese (entry, exit);
- scop = new_scop (sese_reg);
-
- build_sese_loop_nests (sese_reg);
-
- /* Scops with one or no loops are not interesting. */
- if (SESE_LOOP_NEST (sese_reg).length () > 1)
- scops->safe_push (scop);
- else if (dump_file && (dump_flags & TDF_DETAILS))
- fprintf (dump_file, "Discarded scop: %d loops\n",
- SESE_LOOP_NEST (sese_reg).length ());
-
- /* Are there overlapping SCoPs? */
-#ifdef ENABLE_CHECKING
- {
- int j;
- sd_region *s2;
-
- FOR_EACH_VEC_ELT (regions, j, s2)
- if (s != s2)
- gcc_assert (!bb_in_sd_region (s->entry, s2));
- }
-#endif
- }
-}
-
-/* Returns true when P1 and P2 are close phis with the same
- argument. */
-
-static inline bool
-same_close_phi_node (gphi *p1, gphi *p2)
-{
- return operand_equal_p (gimple_phi_arg_def (p1, 0),
- gimple_phi_arg_def (p2, 0), 0);
-}
-
-/* Remove the close phi node at GSI and replace its rhs with the rhs
- of PHI. */
-
-static void
-remove_duplicate_close_phi (gphi *phi, gphi_iterator *gsi)
-{
- gimple *use_stmt;
- use_operand_p use_p;
- imm_use_iterator imm_iter;
- tree res = gimple_phi_result (phi);
- tree def = gimple_phi_result (gsi->phi ());
-
- gcc_assert (same_close_phi_node (phi, gsi->phi ()));
-
- FOR_EACH_IMM_USE_STMT (use_stmt, imm_iter, def)
- {
- FOR_EACH_IMM_USE_ON_STMT (use_p, imm_iter)
- SET_USE (use_p, res);
-
- update_stmt (use_stmt);
-
- /* It is possible that we just created a duplicate close-phi
- for an already-processed containing loop. Check for this
- case and clean it up. */
- if (gimple_code (use_stmt) == GIMPLE_PHI
- && gimple_phi_num_args (use_stmt) == 1)
- make_close_phi_nodes_unique (gimple_bb (use_stmt));
- }
-
- remove_phi_node (gsi, true);
-}
-
-/* Removes all the close phi duplicates from BB. */
-
-static void
-make_close_phi_nodes_unique (basic_block bb)
-{
- gphi_iterator psi;
-
- for (psi = gsi_start_phis (bb); !gsi_end_p (psi); gsi_next (&psi))
- {
- gphi_iterator gsi = psi;
- gphi *phi = psi.phi ();
-
- /* At this point, PHI should be a close phi in normal form. */
- gcc_assert (gimple_phi_num_args (phi) == 1);
-
- /* Iterate over the next phis and remove duplicates. */
- gsi_next (&gsi);
- while (!gsi_end_p (gsi))
- if (same_close_phi_node (phi, gsi.phi ()))
- remove_duplicate_close_phi (phi, &gsi);
- else
- gsi_next (&gsi);
- }
-}
-
-/* Transforms LOOP to the canonical loop closed SSA form. */
-
-static void
-canonicalize_loop_closed_ssa (loop_p loop)
-{
- edge e = single_exit (loop);
- basic_block bb;
-
- if (!e || e->flags & EDGE_ABNORMAL)
- return;
-
- bb = e->dest;
-
- if (single_pred_p (bb))
- {
- e = split_block_after_labels (bb);
- make_close_phi_nodes_unique (e->src);
- }
- else
- {
- gphi_iterator psi;
- basic_block close = split_edge (e);
-
- e = single_succ_edge (close);
-
- for (psi = gsi_start_phis (bb); !gsi_end_p (psi); gsi_next (&psi))
- {
- gphi *phi = psi.phi ();
- unsigned i;
-
- for (i = 0; i < gimple_phi_num_args (phi); i++)
- if (gimple_phi_arg_edge (phi, i) == e)
- {
- tree res, arg = gimple_phi_arg_def (phi, i);
- use_operand_p use_p;
- gphi *close_phi;
-
- if (TREE_CODE (arg) != SSA_NAME)
- continue;
-
- close_phi = create_phi_node (NULL_TREE, close);
- res = create_new_def_for (arg, close_phi,
- gimple_phi_result_ptr (close_phi));
- add_phi_arg (close_phi, arg,
- gimple_phi_arg_edge (close_phi, 0),
- UNKNOWN_LOCATION);
- use_p = gimple_phi_arg_imm_use_ptr (phi, i);
- replace_exp (use_p, res);
- update_stmt (phi);
- }
- }
-
- make_close_phi_nodes_unique (close);
- }
-
- /* The code above does not properly handle changes in the post dominance
- information (yet). */
- free_dominance_info (CDI_POST_DOMINATORS);
-}
-
-/* Converts the current loop closed SSA form to a canonical form
- expected by the Graphite code generation.
-
- The loop closed SSA form has the following invariant: a variable
- defined in a loop that is used outside the loop appears only in the
- phi nodes in the destination of the loop exit. These phi nodes are
- called close phi nodes.
-
- The canonical loop closed SSA form contains the extra invariants:
-
- - when the loop contains only one exit, the close phi nodes contain
- only one argument. That implies that the basic block that contains
- the close phi nodes has only one predecessor, that is a basic block
- in the loop.
-
- - the basic block containing the close phi nodes does not contain
- other statements.
-
- - there exist only one phi node per definition in the loop.
-*/
-
-static void
-canonicalize_loop_closed_ssa_form (void)
-{
- loop_p loop;
-
-#ifdef ENABLE_CHECKING
- verify_loop_closed_ssa (true);
-#endif
-
- FOR_EACH_LOOP (loop, 0)
- canonicalize_loop_closed_ssa (loop);
-
- rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa);
- update_ssa (TODO_update_ssa);
-
-#ifdef ENABLE_CHECKING
- verify_loop_closed_ssa (true);
-#endif
-}
-
-/* Find Static Control Parts (SCoP) in the current function and pushes
- them to SCOPS. */
-
-void
-build_scops (vec<scop_p> *scops)
-{
- struct loop *loop = current_loops->tree_root;
- auto_vec<sd_region, 3> regions;
-
- canonicalize_loop_closed_ssa_form ();
- build_scops_1 (single_succ (ENTRY_BLOCK_PTR_FOR_FN (cfun)),
- ENTRY_BLOCK_PTR_FOR_FN (cfun)->loop_father,
- ®ions, loop);
- create_sese_edges (regions);
- build_graphite_scops (regions, scops);
-
- regions.release ();
-
- if (dump_file && (dump_flags & TDF_DETAILS))
- fprintf (dump_file, "\nnumber of SCoPs: %d\n",
- scops ? scops->length () : 0);
-}
-
-/* Pretty print to FILE all the SCoPs in DOT format and mark them with
- different colors. If there are not enough colors, paint the
- remaining SCoPs in gray.
-
- Special nodes:
- - "*" after the node number denotes the entry of a SCoP,
- - "#" after the node number denotes the exit of a SCoP,
- - "()" around the node number denotes the entry or the
- exit nodes of the SCOP. These are not part of SCoP. */
-
-static void
-dot_all_scops_1 (FILE *file, vec<scop_p> scops)
-{
- basic_block bb;
- edge e;
- edge_iterator ei;
- scop_p scop;
- const char* color;
- int i;
-
- /* Disable debugging while printing graph. */
- int tmp_dump_flags = dump_flags;
- dump_flags = 0;
-
- fprintf (file, "digraph all {\n");
-
- FOR_ALL_BB_FN (bb, cfun)
- {
- int part_of_scop = false;
-
- /* Use HTML for every bb label. So we are able to print bbs
- which are part of two different SCoPs, with two different
- background colors. */
- fprintf (file, "%d [label=<\n <TABLE BORDER=\"0\" CELLBORDER=\"1\" ",
- bb->index);
- fprintf (file, "CELLSPACING=\"0\">\n");
-
- /* Select color for SCoP. */
- FOR_EACH_VEC_ELT (scops, i, scop)
- {
- sese region = SCOP_REGION (scop);
- if (bb_in_sese_p (bb, region)
- || (SESE_EXIT_BB (region) == bb)
- || (SESE_ENTRY_BB (region) == bb))
- {
- switch (i % 17)
- {
- case 0: /* red */
- color = "#e41a1c";
- break;
- case 1: /* blue */
- color = "#377eb8";
- break;
- case 2: /* green */
- color = "#4daf4a";
- break;
- case 3: /* purple */
- color = "#984ea3";
- break;
- case 4: /* orange */
- color = "#ff7f00";
- break;
- case 5: /* yellow */
- color = "#ffff33";
- break;
- case 6: /* brown */
- color = "#a65628";
- break;
- case 7: /* rose */
- color = "#f781bf";
- break;
- case 8:
- color = "#8dd3c7";
- break;
- case 9:
- color = "#ffffb3";
- break;
- case 10:
- color = "#bebada";
- break;
- case 11:
- color = "#fb8072";
- break;
- case 12:
- color = "#80b1d3";
- break;
- case 13:
- color = "#fdb462";
- break;
- case 14:
- color = "#b3de69";
- break;
- case 15:
- color = "#fccde5";
- break;
- case 16:
- color = "#bc80bd";
- break;
- default: /* gray */
- color = "#999999";
- }
-
- fprintf (file, " <TR><TD WIDTH=\"50\" BGCOLOR=\"%s\">", color);
-
- if (!bb_in_sese_p (bb, region))
- fprintf (file, " (");
-
- if (bb == SESE_ENTRY_BB (region)
- && bb == SESE_EXIT_BB (region))
- fprintf (file, " %d*# ", bb->index);
- else if (bb == SESE_ENTRY_BB (region))
- fprintf (file, " %d* ", bb->index);
- else if (bb == SESE_EXIT_BB (region))
- fprintf (file, " %d# ", bb->index);
- else
- fprintf (file, " %d ", bb->index);
-
- if (!bb_in_sese_p (bb,region))
- fprintf (file, ")");
-
- fprintf (file, "</TD></TR>\n");
- part_of_scop = true;
- }
- }
-
- if (!part_of_scop)
- {
- fprintf (file, " <TR><TD WIDTH=\"50\" BGCOLOR=\"#ffffff\">");
- fprintf (file, " %d </TD></TR>\n", bb->index);
- }
- fprintf (file, " </TABLE>>, shape=box, style=\"setlinewidth(0)\"]\n");
- }
-
- FOR_ALL_BB_FN (bb, cfun)
- {
- FOR_EACH_EDGE (e, ei, bb->succs)
- fprintf (file, "%d -> %d;\n", bb->index, e->dest->index);
- }
-
- fputs ("}\n\n", file);
-
- /* Enable debugging again. */
- dump_flags = tmp_dump_flags;
-}
-
-/* Display all SCoPs using dotty. */
-
-DEBUG_FUNCTION void
-dot_all_scops (vec<scop_p> scops)
-{
- /* When debugging, enable the following code. This cannot be used
- in production compilers because it calls "system". */
-#if 0
- int x;
- FILE *stream = fopen ("/tmp/allscops.dot", "w");
- gcc_assert (stream);
-
- dot_all_scops_1 (stream, scops);
- fclose (stream);
-
- x = system ("dotty /tmp/allscops.dot &");
-#else
- dot_all_scops_1 (stderr, scops);
-#endif
-}
-
-/* Display all SCoPs using dotty. */
-
-DEBUG_FUNCTION void
-dot_scop (scop_p scop)
-{
- auto_vec<scop_p, 1> scops;
-
- if (scop)
- scops.safe_push (scop);
-
- /* When debugging, enable the following code. This cannot be used
- in production compilers because it calls "system". */
-#if 0
- {
- int x;
- FILE *stream = fopen ("/tmp/allscops.dot", "w");
- gcc_assert (stream);
-
- dot_all_scops_1 (stream, scops);
- fclose (stream);
- x = system ("dotty /tmp/allscops.dot &");
- }
-#else
- dot_all_scops_1 (stderr, scops);
-#endif
-}
-
-#endif /* HAVE_isl */
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