forked from OSchip/llvm-project
715 lines
26 KiB
C++
715 lines
26 KiB
C++
//===- DependenceInfo.cpp - Calculate dependency information for a Scop. --===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// Calculate the data dependency relations for a Scop using ISL.
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//
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// The integer set library (ISL) from Sven, has a integrated dependency analysis
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// to calculate data dependences. This pass takes advantage of this and
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// calculate those dependences a Scop.
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//
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// The dependences in this pass are exact in terms that for a specific read
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// statement instance only the last write statement instance is returned. In
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// case of may writes a set of possible write instances is returned. This
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// analysis will never produce redundant dependences.
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//
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//===----------------------------------------------------------------------===//
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//
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#include "polly/DependenceInfo.h"
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#include "polly/LinkAllPasses.h"
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#include "polly/Options.h"
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#include "polly/ScopInfo.h"
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#include "polly/Support/GICHelper.h"
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#include "llvm/Support/Debug.h"
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#include <isl/aff.h>
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#include <isl/ctx.h>
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#include <isl/flow.h>
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#include <isl/map.h>
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#include <isl/options.h>
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#include <isl/schedule.h>
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#include <isl/set.h>
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#include <isl/union_map.h>
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#include <isl/union_set.h>
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using namespace polly;
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using namespace llvm;
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#define DEBUG_TYPE "polly-dependence"
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static cl::opt<int> OptComputeOut(
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"polly-dependences-computeout",
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cl::desc("Bound the dependence analysis by a maximal amount of "
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"computational steps (0 means no bound)"),
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cl::Hidden, cl::init(500000), cl::ZeroOrMore, cl::cat(PollyCategory));
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static cl::opt<bool> LegalityCheckDisabled(
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"disable-polly-legality", cl::desc("Disable polly legality check"),
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cl::Hidden, cl::init(false), cl::ZeroOrMore, cl::cat(PollyCategory));
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static cl::opt<bool>
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UseReductions("polly-dependences-use-reductions",
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cl::desc("Exploit reductions in dependence analysis"),
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cl::Hidden, cl::init(true), cl::ZeroOrMore,
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cl::cat(PollyCategory));
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enum AnalysisType { VALUE_BASED_ANALYSIS, MEMORY_BASED_ANALYSIS };
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static cl::opt<enum AnalysisType> OptAnalysisType(
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"polly-dependences-analysis-type",
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cl::desc("The kind of dependence analysis to use"),
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cl::values(clEnumValN(VALUE_BASED_ANALYSIS, "value-based",
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"Exact dependences without transitive dependences"),
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clEnumValN(MEMORY_BASED_ANALYSIS, "memory-based",
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"Overapproximation of dependences"),
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clEnumValEnd),
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cl::Hidden, cl::init(VALUE_BASED_ANALYSIS), cl::ZeroOrMore,
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cl::cat(PollyCategory));
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//===----------------------------------------------------------------------===//
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/// @brief Collect information about the SCoP @p S.
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static void collectInfo(Scop &S, isl_union_map **Read, isl_union_map **Write,
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isl_union_map **MayWrite,
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isl_union_map **AccessSchedule,
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isl_union_map **StmtSchedule) {
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isl_space *Space = S.getParamSpace();
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*Read = isl_union_map_empty(isl_space_copy(Space));
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*Write = isl_union_map_empty(isl_space_copy(Space));
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*MayWrite = isl_union_map_empty(isl_space_copy(Space));
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*AccessSchedule = isl_union_map_empty(isl_space_copy(Space));
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*StmtSchedule = isl_union_map_empty(Space);
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SmallPtrSet<const Value *, 8> ReductionBaseValues;
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if (UseReductions)
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for (ScopStmt &Stmt : S)
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for (MemoryAccess *MA : Stmt)
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if (MA->isReductionLike())
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ReductionBaseValues.insert(MA->getBaseAddr());
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for (ScopStmt &Stmt : S) {
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for (MemoryAccess *MA : Stmt) {
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isl_set *domcp = Stmt.getDomain();
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isl_map *accdom = MA->getAccessRelation();
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accdom = isl_map_intersect_domain(accdom, domcp);
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if (ReductionBaseValues.count(MA->getBaseAddr())) {
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// Wrap the access domain and adjust the schedule accordingly.
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//
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// An access domain like
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// Stmt[i0, i1] -> MemAcc_A[i0 + i1]
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// will be transformed into
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// [Stmt[i0, i1] -> MemAcc_A[i0 + i1]] -> MemAcc_A[i0 + i1]
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//
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// The original schedule looks like
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// Stmt[i0, i1] -> [0, i0, 2, i1, 0]
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// but as we transformed the access domain we need the schedule
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// to match the new access domains, thus we need
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// [Stmt[i0, i1] -> MemAcc_A[i0 + i1]] -> [0, i0, 2, i1, 0]
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isl_map *Schedule = Stmt.getSchedule();
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Schedule = isl_map_apply_domain(
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Schedule,
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isl_map_reverse(isl_map_domain_map(isl_map_copy(accdom))));
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accdom = isl_map_range_map(accdom);
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*AccessSchedule = isl_union_map_add_map(*AccessSchedule, Schedule);
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}
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if (MA->isRead())
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*Read = isl_union_map_add_map(*Read, accdom);
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else
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*Write = isl_union_map_add_map(*Write, accdom);
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}
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*StmtSchedule = isl_union_map_add_map(*StmtSchedule, Stmt.getSchedule());
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}
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*StmtSchedule =
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isl_union_map_intersect_params(*StmtSchedule, S.getAssumedContext());
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}
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/// @brief Fix all dimension of @p Zero to 0 and add it to @p user
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static isl_stat fixSetToZero(__isl_take isl_set *Zero, void *user) {
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isl_union_set **User = (isl_union_set **)user;
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for (unsigned i = 0; i < isl_set_dim(Zero, isl_dim_set); i++)
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Zero = isl_set_fix_si(Zero, isl_dim_set, i, 0);
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*User = isl_union_set_add_set(*User, Zero);
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return isl_stat_ok;
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}
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/// @brief Compute the privatization dependences for a given dependency @p Map
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///
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/// Privatization dependences are widened original dependences which originate
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/// or end in a reduction access. To compute them we apply the transitive close
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/// of the reduction dependences (which maps each iteration of a reduction
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/// statement to all following ones) on the RAW/WAR/WAW dependences. The
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/// dependences which start or end at a reduction statement will be extended to
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/// depend on all following reduction statement iterations as well.
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/// Note: "Following" here means according to the reduction dependences.
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///
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/// For the input:
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///
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/// S0: *sum = 0;
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/// for (int i = 0; i < 1024; i++)
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/// S1: *sum += i;
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/// S2: *sum = *sum * 3;
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///
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/// we have the following dependences before we add privatization dependences:
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///
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/// RAW:
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/// { S0[] -> S1[0]; S1[1023] -> S2[] }
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/// WAR:
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/// { }
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/// WAW:
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/// { S0[] -> S1[0]; S1[1024] -> S2[] }
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/// RED:
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/// { S1[i0] -> S1[1 + i0] : i0 >= 0 and i0 <= 1022 }
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///
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/// and afterwards:
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///
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/// RAW:
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/// { S0[] -> S1[i0] : i0 >= 0 and i0 <= 1023;
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/// S1[i0] -> S2[] : i0 >= 0 and i0 <= 1023}
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/// WAR:
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/// { }
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/// WAW:
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/// { S0[] -> S1[i0] : i0 >= 0 and i0 <= 1023;
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/// S1[i0] -> S2[] : i0 >= 0 and i0 <= 1023}
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/// RED:
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/// { S1[i0] -> S1[1 + i0] : i0 >= 0 and i0 <= 1022 }
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///
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/// Note: This function also computes the (reverse) transitive closure of the
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/// reduction dependences.
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void Dependences::addPrivatizationDependences() {
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isl_union_map *PrivRAW, *PrivWAW, *PrivWAR;
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// The transitive closure might be over approximated, thus could lead to
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// dependency cycles in the privatization dependences. To make sure this
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// will not happen we remove all negative dependences after we computed
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// the transitive closure.
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TC_RED = isl_union_map_transitive_closure(isl_union_map_copy(RED), 0);
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// FIXME: Apply the current schedule instead of assuming the identity schedule
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// here. The current approach is only valid as long as we compute the
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// dependences only with the initial (identity schedule). Any other
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// schedule could change "the direction of the backward dependences" we
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// want to eliminate here.
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isl_union_set *UDeltas = isl_union_map_deltas(isl_union_map_copy(TC_RED));
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isl_union_set *Universe = isl_union_set_universe(isl_union_set_copy(UDeltas));
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isl_union_set *Zero = isl_union_set_empty(isl_union_set_get_space(Universe));
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isl_union_set_foreach_set(Universe, fixSetToZero, &Zero);
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isl_union_map *NonPositive = isl_union_set_lex_le_union_set(UDeltas, Zero);
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TC_RED = isl_union_map_subtract(TC_RED, NonPositive);
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TC_RED = isl_union_map_union(
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TC_RED, isl_union_map_reverse(isl_union_map_copy(TC_RED)));
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TC_RED = isl_union_map_coalesce(TC_RED);
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isl_union_map **Maps[] = {&RAW, &WAW, &WAR};
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isl_union_map **PrivMaps[] = {&PrivRAW, &PrivWAW, &PrivWAR};
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for (unsigned u = 0; u < 3; u++) {
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isl_union_map **Map = Maps[u], **PrivMap = PrivMaps[u];
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*PrivMap = isl_union_map_apply_range(isl_union_map_copy(*Map),
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isl_union_map_copy(TC_RED));
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*PrivMap = isl_union_map_union(
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*PrivMap, isl_union_map_apply_range(isl_union_map_copy(TC_RED),
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isl_union_map_copy(*Map)));
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*Map = isl_union_map_union(*Map, *PrivMap);
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}
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isl_union_set_free(Universe);
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}
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static isl_stat getMaxScheduleDim(__isl_take isl_map *Map, void *User) {
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unsigned int *MaxScheduleDim = (unsigned int *)User;
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*MaxScheduleDim = std::max(*MaxScheduleDim, isl_map_dim(Map, isl_dim_out));
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isl_map_free(Map);
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return isl_stat_ok;
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}
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__isl_give isl_union_map *
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addZeroPaddingToSchedule(__isl_take isl_union_map *Schedule) {
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unsigned int MaxScheduleDim = 0;
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isl_union_map_foreach_map(Schedule, getMaxScheduleDim, &MaxScheduleDim);
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auto ExtensionMap = isl_union_map_empty(isl_union_map_get_space(Schedule));
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for (unsigned int i = 0; i <= MaxScheduleDim; i++) {
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auto *Map = isl_map_identity(
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isl_space_alloc(isl_union_map_get_ctx(Schedule), 0, i, i));
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Map = isl_map_add_dims(Map, isl_dim_out, MaxScheduleDim - i);
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for (unsigned int j = 0; j < MaxScheduleDim - i; j++)
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Map = isl_map_fix_si(Map, isl_dim_out, i + j, 0);
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ExtensionMap = isl_union_map_add_map(ExtensionMap, Map);
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}
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Schedule = isl_union_map_apply_range(Schedule, ExtensionMap);
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return Schedule;
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}
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void Dependences::calculateDependences(Scop &S) {
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isl_union_map *Read, *Write, *MayWrite, *AccessSchedule, *StmtSchedule;
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isl_schedule *Schedule;
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DEBUG(dbgs() << "Scop: \n" << S << "\n");
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collectInfo(S, &Read, &Write, &MayWrite, &AccessSchedule, &StmtSchedule);
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if (isl_union_map_is_empty(AccessSchedule)) {
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isl_union_map_free(AccessSchedule);
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Schedule = S.getScheduleTree();
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} else {
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auto *ScheduleMap =
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isl_union_map_union(AccessSchedule, isl_union_map_copy(StmtSchedule));
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Schedule = isl_schedule_from_domain(
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isl_union_map_domain(isl_union_map_copy(ScheduleMap)));
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if (!isl_union_map_is_empty(ScheduleMap)) {
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ScheduleMap = addZeroPaddingToSchedule(ScheduleMap);
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Schedule = isl_schedule_insert_partial_schedule(
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Schedule, isl_multi_union_pw_aff_from_union_map(ScheduleMap));
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} else {
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isl_union_map_free(ScheduleMap);
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}
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}
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Read = isl_union_map_coalesce(Read);
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Write = isl_union_map_coalesce(Write);
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MayWrite = isl_union_map_coalesce(MayWrite);
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long MaxOpsOld = isl_ctx_get_max_operations(S.getIslCtx());
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if (OptComputeOut)
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isl_ctx_set_max_operations(S.getIslCtx(), OptComputeOut);
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isl_options_set_on_error(S.getIslCtx(), ISL_ON_ERROR_CONTINUE);
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DEBUG(dbgs() << "Read: " << Read << "\n";
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dbgs() << "Write: " << Write << "\n";
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dbgs() << "MayWrite: " << MayWrite << "\n");
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RAW = WAW = WAR = RED = nullptr;
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if (OptAnalysisType == VALUE_BASED_ANALYSIS) {
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isl_union_access_info *AI;
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isl_union_flow *Flow;
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AI = isl_union_access_info_from_sink(isl_union_map_copy(Read));
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AI = isl_union_access_info_set_must_source(AI, isl_union_map_copy(Write));
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AI = isl_union_access_info_set_may_source(AI, isl_union_map_copy(MayWrite));
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AI = isl_union_access_info_set_schedule(AI, isl_schedule_copy(Schedule));
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Flow = isl_union_access_info_compute_flow(AI);
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RAW = isl_union_flow_get_must_dependence(Flow);
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isl_union_flow_free(Flow);
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AI = isl_union_access_info_from_sink(isl_union_map_copy(Write));
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AI = isl_union_access_info_set_must_source(AI, isl_union_map_copy(Write));
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AI = isl_union_access_info_set_may_source(AI, isl_union_map_copy(Read));
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AI = isl_union_access_info_set_schedule(AI, Schedule);
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Flow = isl_union_access_info_compute_flow(AI);
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WAW = isl_union_flow_get_must_dependence(Flow);
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WAR = isl_union_flow_get_may_dependence(Flow);
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// This subtraction is needed to obtain the same results as were given by
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// isl_union_map_compute_flow. For large sets this may add some compile-time
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// cost. As there does not seem to be a need to distinguish between WAW and
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// WAR, refactoring Polly to only track general non-flow dependences may
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// improve performance.
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WAR = isl_union_map_subtract(WAR, isl_union_map_copy(WAW));
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isl_union_flow_free(Flow);
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} else {
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isl_union_access_info *AI;
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isl_union_flow *Flow;
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Write = isl_union_map_union(Write, isl_union_map_copy(MayWrite));
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AI = isl_union_access_info_from_sink(isl_union_map_copy(Read));
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AI = isl_union_access_info_set_may_source(AI, isl_union_map_copy(Write));
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AI = isl_union_access_info_set_schedule(AI, isl_schedule_copy(Schedule));
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Flow = isl_union_access_info_compute_flow(AI);
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RAW = isl_union_flow_get_may_dependence(Flow);
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isl_union_flow_free(Flow);
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AI = isl_union_access_info_from_sink(isl_union_map_copy(Write));
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AI = isl_union_access_info_set_may_source(AI, isl_union_map_copy(Read));
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AI = isl_union_access_info_set_schedule(AI, isl_schedule_copy(Schedule));
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Flow = isl_union_access_info_compute_flow(AI);
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WAR = isl_union_flow_get_may_dependence(Flow);
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isl_union_flow_free(Flow);
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AI = isl_union_access_info_from_sink(isl_union_map_copy(Write));
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AI = isl_union_access_info_set_may_source(AI, isl_union_map_copy(Write));
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AI = isl_union_access_info_set_schedule(AI, Schedule);
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Flow = isl_union_access_info_compute_flow(AI);
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WAW = isl_union_flow_get_may_dependence(Flow);
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isl_union_flow_free(Flow);
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}
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isl_union_map_free(MayWrite);
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isl_union_map_free(Write);
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isl_union_map_free(Read);
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RAW = isl_union_map_coalesce(RAW);
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WAW = isl_union_map_coalesce(WAW);
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WAR = isl_union_map_coalesce(WAR);
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if (isl_ctx_last_error(S.getIslCtx()) == isl_error_quota) {
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isl_union_map_free(RAW);
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isl_union_map_free(WAW);
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isl_union_map_free(WAR);
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RAW = WAW = WAR = nullptr;
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isl_ctx_reset_error(S.getIslCtx());
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}
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isl_options_set_on_error(S.getIslCtx(), ISL_ON_ERROR_ABORT);
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isl_ctx_reset_operations(S.getIslCtx());
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isl_ctx_set_max_operations(S.getIslCtx(), MaxOpsOld);
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isl_union_map *STMT_RAW, *STMT_WAW, *STMT_WAR;
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STMT_RAW = isl_union_map_intersect_domain(
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isl_union_map_copy(RAW),
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isl_union_map_domain(isl_union_map_copy(StmtSchedule)));
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STMT_WAW = isl_union_map_intersect_domain(
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isl_union_map_copy(WAW),
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isl_union_map_domain(isl_union_map_copy(StmtSchedule)));
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STMT_WAR = isl_union_map_intersect_domain(isl_union_map_copy(WAR),
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isl_union_map_domain(StmtSchedule));
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DEBUG({
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dbgs() << "Wrapped Dependences:\n";
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dump();
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dbgs() << "\n";
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});
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// To handle reduction dependences we proceed as follows:
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// 1) Aggregate all possible reduction dependences, namely all self
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// dependences on reduction like statements.
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// 2) Intersect them with the actual RAW & WAW dependences to the get the
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// actual reduction dependences. This will ensure the load/store memory
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// addresses were __identical__ in the two iterations of the statement.
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// 3) Relax the original RAW and WAW dependences by subtracting the actual
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// reduction dependences. Binary reductions (sum += A[i]) cause both, and
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// the same, RAW and WAW dependences.
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// 4) Add the privatization dependences which are widened versions of
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// already present dependences. They model the effect of manual
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// privatization at the outermost possible place (namely after the last
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// write and before the first access to a reduction location).
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// Step 1)
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RED = isl_union_map_empty(isl_union_map_get_space(RAW));
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for (ScopStmt &Stmt : S) {
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for (MemoryAccess *MA : Stmt) {
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if (!MA->isReductionLike())
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continue;
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isl_set *AccDomW = isl_map_wrap(MA->getAccessRelation());
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isl_map *Identity =
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isl_map_from_domain_and_range(isl_set_copy(AccDomW), AccDomW);
|
|
RED = isl_union_map_add_map(RED, Identity);
|
|
}
|
|
}
|
|
|
|
// Step 2)
|
|
RED = isl_union_map_intersect(RED, isl_union_map_copy(RAW));
|
|
RED = isl_union_map_intersect(RED, isl_union_map_copy(WAW));
|
|
|
|
if (!isl_union_map_is_empty(RED)) {
|
|
|
|
// Step 3)
|
|
RAW = isl_union_map_subtract(RAW, isl_union_map_copy(RED));
|
|
WAW = isl_union_map_subtract(WAW, isl_union_map_copy(RED));
|
|
|
|
// Step 4)
|
|
addPrivatizationDependences();
|
|
}
|
|
|
|
DEBUG({
|
|
dbgs() << "Final Wrapped Dependences:\n";
|
|
dump();
|
|
dbgs() << "\n";
|
|
});
|
|
|
|
// RED_SIN is used to collect all reduction dependences again after we
|
|
// split them according to the causing memory accesses. The current assumption
|
|
// is that our method of splitting will not have any leftovers. In the end
|
|
// we validate this assumption until we have more confidence in this method.
|
|
isl_union_map *RED_SIN = isl_union_map_empty(isl_union_map_get_space(RAW));
|
|
|
|
// For each reduction like memory access, check if there are reduction
|
|
// dependences with the access relation of the memory access as a domain
|
|
// (wrapped space!). If so these dependences are caused by this memory access.
|
|
// We then move this portion of reduction dependences back to the statement ->
|
|
// statement space and add a mapping from the memory access to these
|
|
// dependences.
|
|
for (ScopStmt &Stmt : S) {
|
|
for (MemoryAccess *MA : Stmt) {
|
|
if (!MA->isReductionLike())
|
|
continue;
|
|
|
|
isl_set *AccDomW = isl_map_wrap(MA->getAccessRelation());
|
|
isl_union_map *AccRedDepU = isl_union_map_intersect_domain(
|
|
isl_union_map_copy(TC_RED), isl_union_set_from_set(AccDomW));
|
|
if (isl_union_map_is_empty(AccRedDepU) && !isl_union_map_free(AccRedDepU))
|
|
continue;
|
|
|
|
isl_map *AccRedDep = isl_map_from_union_map(AccRedDepU);
|
|
RED_SIN = isl_union_map_add_map(RED_SIN, isl_map_copy(AccRedDep));
|
|
AccRedDep = isl_map_zip(AccRedDep);
|
|
AccRedDep = isl_set_unwrap(isl_map_domain(AccRedDep));
|
|
setReductionDependences(MA, AccRedDep);
|
|
}
|
|
}
|
|
|
|
assert(isl_union_map_is_equal(RED_SIN, TC_RED) &&
|
|
"Intersecting the reduction dependence domain with the wrapped access "
|
|
"relation is not enough, we need to loosen the access relation also");
|
|
isl_union_map_free(RED_SIN);
|
|
|
|
RAW = isl_union_map_zip(RAW);
|
|
WAW = isl_union_map_zip(WAW);
|
|
WAR = isl_union_map_zip(WAR);
|
|
RED = isl_union_map_zip(RED);
|
|
TC_RED = isl_union_map_zip(TC_RED);
|
|
|
|
DEBUG({
|
|
dbgs() << "Zipped Dependences:\n";
|
|
dump();
|
|
dbgs() << "\n";
|
|
});
|
|
|
|
RAW = isl_union_set_unwrap(isl_union_map_domain(RAW));
|
|
WAW = isl_union_set_unwrap(isl_union_map_domain(WAW));
|
|
WAR = isl_union_set_unwrap(isl_union_map_domain(WAR));
|
|
RED = isl_union_set_unwrap(isl_union_map_domain(RED));
|
|
TC_RED = isl_union_set_unwrap(isl_union_map_domain(TC_RED));
|
|
|
|
DEBUG({
|
|
dbgs() << "Unwrapped Dependences:\n";
|
|
dump();
|
|
dbgs() << "\n";
|
|
});
|
|
|
|
RAW = isl_union_map_union(RAW, STMT_RAW);
|
|
WAW = isl_union_map_union(WAW, STMT_WAW);
|
|
WAR = isl_union_map_union(WAR, STMT_WAR);
|
|
|
|
RAW = isl_union_map_coalesce(RAW);
|
|
WAW = isl_union_map_coalesce(WAW);
|
|
WAR = isl_union_map_coalesce(WAR);
|
|
RED = isl_union_map_coalesce(RED);
|
|
TC_RED = isl_union_map_coalesce(TC_RED);
|
|
|
|
DEBUG(dump());
|
|
}
|
|
|
|
bool Dependences::isValidSchedule(Scop &S,
|
|
StatementToIslMapTy *NewSchedule) const {
|
|
if (LegalityCheckDisabled)
|
|
return true;
|
|
|
|
isl_union_map *Dependences = getDependences(TYPE_RAW | TYPE_WAW | TYPE_WAR);
|
|
isl_space *Space = S.getParamSpace();
|
|
isl_union_map *Schedule = isl_union_map_empty(Space);
|
|
|
|
isl_space *ScheduleSpace = nullptr;
|
|
|
|
for (ScopStmt &Stmt : S) {
|
|
isl_map *StmtScat;
|
|
|
|
if (NewSchedule->find(&Stmt) == NewSchedule->end())
|
|
StmtScat = Stmt.getSchedule();
|
|
else
|
|
StmtScat = isl_map_copy((*NewSchedule)[&Stmt]);
|
|
|
|
if (!ScheduleSpace)
|
|
ScheduleSpace = isl_space_range(isl_map_get_space(StmtScat));
|
|
|
|
Schedule = isl_union_map_add_map(Schedule, StmtScat);
|
|
}
|
|
|
|
Dependences =
|
|
isl_union_map_apply_domain(Dependences, isl_union_map_copy(Schedule));
|
|
Dependences = isl_union_map_apply_range(Dependences, Schedule);
|
|
|
|
isl_set *Zero = isl_set_universe(isl_space_copy(ScheduleSpace));
|
|
for (unsigned i = 0; i < isl_set_dim(Zero, isl_dim_set); i++)
|
|
Zero = isl_set_fix_si(Zero, isl_dim_set, i, 0);
|
|
|
|
isl_union_set *UDeltas = isl_union_map_deltas(Dependences);
|
|
isl_set *Deltas = isl_union_set_extract_set(UDeltas, ScheduleSpace);
|
|
isl_union_set_free(UDeltas);
|
|
|
|
isl_map *NonPositive = isl_set_lex_le_set(Deltas, Zero);
|
|
bool IsValid = isl_map_is_empty(NonPositive);
|
|
isl_map_free(NonPositive);
|
|
|
|
return IsValid;
|
|
}
|
|
|
|
// Check if the current scheduling dimension is parallel.
|
|
//
|
|
// We check for parallelism by verifying that the loop does not carry any
|
|
// dependences.
|
|
//
|
|
// Parallelism test: if the distance is zero in all outer dimensions, then it
|
|
// has to be zero in the current dimension as well.
|
|
//
|
|
// Implementation: first, translate dependences into time space, then force
|
|
// outer dimensions to be equal. If the distance is zero in the current
|
|
// dimension, then the loop is parallel. The distance is zero in the current
|
|
// dimension if it is a subset of a map with equal values for the current
|
|
// dimension.
|
|
bool Dependences::isParallel(isl_union_map *Schedule, isl_union_map *Deps,
|
|
isl_pw_aff **MinDistancePtr) const {
|
|
isl_set *Deltas, *Distance;
|
|
isl_map *ScheduleDeps;
|
|
unsigned Dimension;
|
|
bool IsParallel;
|
|
|
|
Deps = isl_union_map_apply_range(Deps, isl_union_map_copy(Schedule));
|
|
Deps = isl_union_map_apply_domain(Deps, isl_union_map_copy(Schedule));
|
|
|
|
if (isl_union_map_is_empty(Deps)) {
|
|
isl_union_map_free(Deps);
|
|
return true;
|
|
}
|
|
|
|
ScheduleDeps = isl_map_from_union_map(Deps);
|
|
Dimension = isl_map_dim(ScheduleDeps, isl_dim_out) - 1;
|
|
|
|
for (unsigned i = 0; i < Dimension; i++)
|
|
ScheduleDeps = isl_map_equate(ScheduleDeps, isl_dim_out, i, isl_dim_in, i);
|
|
|
|
Deltas = isl_map_deltas(ScheduleDeps);
|
|
Distance = isl_set_universe(isl_set_get_space(Deltas));
|
|
|
|
// [0, ..., 0, +] - All zeros and last dimension larger than zero
|
|
for (unsigned i = 0; i < Dimension; i++)
|
|
Distance = isl_set_fix_si(Distance, isl_dim_set, i, 0);
|
|
|
|
Distance = isl_set_lower_bound_si(Distance, isl_dim_set, Dimension, 1);
|
|
Distance = isl_set_intersect(Distance, Deltas);
|
|
|
|
IsParallel = isl_set_is_empty(Distance);
|
|
if (IsParallel || !MinDistancePtr) {
|
|
isl_set_free(Distance);
|
|
return IsParallel;
|
|
}
|
|
|
|
Distance = isl_set_project_out(Distance, isl_dim_set, 0, Dimension);
|
|
Distance = isl_set_coalesce(Distance);
|
|
|
|
// This last step will compute a expression for the minimal value in the
|
|
// distance polyhedron Distance with regards to the first (outer most)
|
|
// dimension.
|
|
*MinDistancePtr = isl_pw_aff_coalesce(isl_set_dim_min(Distance, 0));
|
|
|
|
return false;
|
|
}
|
|
|
|
static void printDependencyMap(raw_ostream &OS, __isl_keep isl_union_map *DM) {
|
|
if (DM)
|
|
OS << DM << "\n";
|
|
else
|
|
OS << "n/a\n";
|
|
}
|
|
|
|
void Dependences::print(raw_ostream &OS) const {
|
|
OS << "\tRAW dependences:\n\t\t";
|
|
printDependencyMap(OS, RAW);
|
|
OS << "\tWAR dependences:\n\t\t";
|
|
printDependencyMap(OS, WAR);
|
|
OS << "\tWAW dependences:\n\t\t";
|
|
printDependencyMap(OS, WAW);
|
|
OS << "\tReduction dependences:\n\t\t";
|
|
printDependencyMap(OS, RED);
|
|
OS << "\tTransitive closure of reduction dependences:\n\t\t";
|
|
printDependencyMap(OS, TC_RED);
|
|
}
|
|
|
|
void Dependences::dump() const { print(dbgs()); }
|
|
|
|
void Dependences::releaseMemory() {
|
|
isl_union_map_free(RAW);
|
|
isl_union_map_free(WAR);
|
|
isl_union_map_free(WAW);
|
|
isl_union_map_free(RED);
|
|
isl_union_map_free(TC_RED);
|
|
|
|
RED = RAW = WAR = WAW = TC_RED = nullptr;
|
|
|
|
for (auto &ReductionDeps : ReductionDependences)
|
|
isl_map_free(ReductionDeps.second);
|
|
ReductionDependences.clear();
|
|
}
|
|
|
|
isl_union_map *Dependences::getDependences(int Kinds) const {
|
|
assert(hasValidDependences() && "No valid dependences available");
|
|
isl_space *Space = isl_union_map_get_space(RAW);
|
|
isl_union_map *Deps = isl_union_map_empty(Space);
|
|
|
|
if (Kinds & TYPE_RAW)
|
|
Deps = isl_union_map_union(Deps, isl_union_map_copy(RAW));
|
|
|
|
if (Kinds & TYPE_WAR)
|
|
Deps = isl_union_map_union(Deps, isl_union_map_copy(WAR));
|
|
|
|
if (Kinds & TYPE_WAW)
|
|
Deps = isl_union_map_union(Deps, isl_union_map_copy(WAW));
|
|
|
|
if (Kinds & TYPE_RED)
|
|
Deps = isl_union_map_union(Deps, isl_union_map_copy(RED));
|
|
|
|
if (Kinds & TYPE_TC_RED)
|
|
Deps = isl_union_map_union(Deps, isl_union_map_copy(TC_RED));
|
|
|
|
Deps = isl_union_map_coalesce(Deps);
|
|
Deps = isl_union_map_detect_equalities(Deps);
|
|
return Deps;
|
|
}
|
|
|
|
bool Dependences::hasValidDependences() const {
|
|
return (RAW != nullptr) && (WAR != nullptr) && (WAW != nullptr);
|
|
}
|
|
|
|
isl_map *Dependences::getReductionDependences(MemoryAccess *MA) const {
|
|
return isl_map_copy(ReductionDependences.lookup(MA));
|
|
}
|
|
|
|
void Dependences::setReductionDependences(MemoryAccess *MA, isl_map *D) {
|
|
assert(ReductionDependences.count(MA) == 0 &&
|
|
"Reduction dependences set twice!");
|
|
ReductionDependences[MA] = D;
|
|
}
|
|
|
|
void DependenceInfo::recomputeDependences() {
|
|
releaseMemory();
|
|
D.calculateDependences(*S);
|
|
}
|
|
|
|
bool DependenceInfo::runOnScop(Scop &ScopVar) {
|
|
S = &ScopVar;
|
|
recomputeDependences();
|
|
return false;
|
|
}
|
|
|
|
void DependenceInfo::getAnalysisUsage(AnalysisUsage &AU) const {
|
|
ScopPass::getAnalysisUsage(AU);
|
|
}
|
|
|
|
char DependenceInfo::ID = 0;
|
|
|
|
Pass *polly::createDependenceInfoPass() { return new DependenceInfo(); }
|
|
|
|
INITIALIZE_PASS_BEGIN(DependenceInfo, "polly-dependences",
|
|
"Polly - Calculate dependences", false, false);
|
|
INITIALIZE_PASS_DEPENDENCY(ScopInfo);
|
|
INITIALIZE_PASS_END(DependenceInfo, "polly-dependences",
|
|
"Polly - Calculate dependences", false, false)
|