Coverage Report

Created: 2019-04-25 15:07

/Users/buildslave/jenkins/workspace/clang-stage2-coverage-R/llvm/tools/polly/lib/Transform/ZoneAlgo.cpp
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//===------ ZoneAlgo.cpp ----------------------------------------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// Derive information about array elements between statements ("Zones").
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//
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// The algorithms here work on the scatter space - the image space of the
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// schedule returned by Scop::getSchedule(). We call an element in that space a
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// "timepoint". Timepoints are lexicographically ordered such that we can
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// defined ranges in the scatter space. We use two flavors of such ranges:
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// Timepoint sets and zones. A timepoint set is simply a subset of the scatter
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// space and is directly stored as isl_set.
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//
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// Zones are used to describe the space between timepoints as open sets, i.e.
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// they do not contain the extrema. Using isl rational sets to express these
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// would be overkill. We also cannot store them as the integer timepoints they
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// contain; the (nonempty) zone between 1 and 2 would be empty and
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// indistinguishable from e.g. the zone between 3 and 4. Also, we cannot store
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// the integer set including the extrema; the set ]1,2[ + ]3,4[ could be
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// coalesced to ]1,3[, although we defined the range [2,3] to be not in the set.
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// Instead, we store the "half-open" integer extrema, including the lower bound,
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// but excluding the upper bound. Examples:
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//
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// * The set { [i] : 1 <= i <= 3 } represents the zone ]0,3[ (which contains the
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//   integer points 1 and 2, but not 0 or 3)
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//
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// * { [1] } represents the zone ]0,1[
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//
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// * { [i] : i = 1 or i = 3 } represents the zone ]0,1[ + ]2,3[
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//
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// Therefore, an integer i in the set represents the zone ]i-1,i[, i.e. strictly
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// speaking the integer points never belong to the zone. However, depending an
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// the interpretation, one might want to include them. Part of the
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// interpretation may not be known when the zone is constructed.
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//
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// Reads are assumed to always take place before writes, hence we can think of
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// reads taking place at the beginning of a timepoint and writes at the end.
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//
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// Let's assume that the zone represents the lifetime of a variable. That is,
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// the zone begins with a write that defines the value during its lifetime and
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// ends with the last read of that value. In the following we consider whether a
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// read/write at the beginning/ending of the lifetime zone should be within the
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// zone or outside of it.
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//
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// * A read at the timepoint that starts the live-range loads the previous
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//   value. Hence, exclude the timepoint starting the zone.
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//
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// * A write at the timepoint that starts the live-range is not defined whether
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//   it occurs before or after the write that starts the lifetime. We do not
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//   allow this situation to occur. Hence, we include the timepoint starting the
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//   zone to determine whether they are conflicting.
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//
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// * A read at the timepoint that ends the live-range reads the same variable.
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//   We include the timepoint at the end of the zone to include that read into
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//   the live-range. Doing otherwise would mean that the two reads access
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//   different values, which would mean that the value they read are both alive
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//   at the same time but occupy the same variable.
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//
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// * A write at the timepoint that ends the live-range starts a new live-range.
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//   It must not be included in the live-range of the previous definition.
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//
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// All combinations of reads and writes at the endpoints are possible, but most
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// of the time only the write->read (for instance, a live-range from definition
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// to last use) and read->write (for instance, an unused range from last use to
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// overwrite) and combinations are interesting (half-open ranges). write->write
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// zones might be useful as well in some context to represent
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// output-dependencies.
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//
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// @see convertZoneToTimepoints
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//
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//
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// The code makes use of maps and sets in many different spaces. To not loose
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// track in which space a set or map is expected to be in, variables holding an
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// isl reference are usually annotated in the comments. They roughly follow isl
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// syntax for spaces, but only the tuples, not the dimensions. The tuples have a
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// meaning as follows:
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//
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// * Space[] - An unspecified tuple. Used for function parameters such that the
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//             function caller can use it for anything they like.
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//
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// * Domain[] - A statement instance as returned by ScopStmt::getDomain()
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//     isl_id_get_name: Stmt_<NameOfBasicBlock>
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//     isl_id_get_user: Pointer to ScopStmt
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//
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// * Element[] - An array element as in the range part of
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//               MemoryAccess::getAccessRelation()
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//     isl_id_get_name: MemRef_<NameOfArrayVariable>
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//     isl_id_get_user: Pointer to ScopArrayInfo
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//
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// * Scatter[] - Scatter space or space of timepoints
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//     Has no tuple id
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//
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// * Zone[] - Range between timepoints as described above
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//     Has no tuple id
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//
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// * ValInst[] - An llvm::Value as defined at a specific timepoint.
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//
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//     A ValInst[] itself can be structured as one of:
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//
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//     * [] - An unknown value.
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//         Always zero dimensions
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//         Has no tuple id
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//
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//     * Value[] - An llvm::Value that is read-only in the SCoP, i.e. its
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//                 runtime content does not depend on the timepoint.
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//         Always zero dimensions
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//         isl_id_get_name: Val_<NameOfValue>
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//         isl_id_get_user: A pointer to an llvm::Value
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//
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//     * SCEV[...] - A synthesizable llvm::SCEV Expression.
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//         In contrast to a Value[] is has at least one dimension per
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//         SCEVAddRecExpr in the SCEV.
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//
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//     * [Domain[] -> Value[]] - An llvm::Value that may change during the
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//                               Scop's execution.
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//         The tuple itself has no id, but it wraps a map space holding a
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//         statement instance which defines the llvm::Value as the map's domain
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//         and llvm::Value itself as range.
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//
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// @see makeValInst()
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//
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// An annotation "{ Domain[] -> Scatter[] }" therefore means: A map from a
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// statement instance to a timepoint, aka a schedule. There is only one scatter
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// space, but most of the time multiple statements are processed in one set.
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// This is why most of the time isl_union_map has to be used.
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//
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// The basic algorithm works as follows:
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// At first we verify that the SCoP is compatible with this technique. For
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// instance, two writes cannot write to the same location at the same statement
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// instance because we cannot determine within the polyhedral model which one
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// comes first. Once this was verified, we compute zones at which an array
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// element is unused. This computation can fail if it takes too long. Then the
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// main algorithm is executed. Because every store potentially trails an unused
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// zone, we start at stores. We search for a scalar (MemoryKind::Value or
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// MemoryKind::PHI) that we can map to the array element overwritten by the
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// store, preferably one that is used by the store or at least the ScopStmt.
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// When it does not conflict with the lifetime of the values in the array
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// element, the map is applied and the unused zone updated as it is now used. We
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// continue to try to map scalars to the array element until there are no more
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// candidates to map. The algorithm is greedy in the sense that the first scalar
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// not conflicting will be mapped. Other scalars processed later that could have
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// fit the same unused zone will be rejected. As such the result depends on the
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// processing order.
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//
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//===----------------------------------------------------------------------===//
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#include "polly/ZoneAlgo.h"
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#include "polly/ScopInfo.h"
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#include "polly/Support/GICHelper.h"
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#include "polly/Support/ISLTools.h"
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#include "polly/Support/VirtualInstruction.h"
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#include "llvm/ADT/Statistic.h"
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#include "llvm/Support/raw_ostream.h"
158
159
#define DEBUG_TYPE "polly-zone"
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STATISTIC(NumIncompatibleArrays, "Number of not zone-analyzable arrays");
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STATISTIC(NumCompatibleArrays, "Number of zone-analyzable arrays");
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STATISTIC(NumRecursivePHIs, "Number of recursive PHIs");
164
STATISTIC(NumNormalizablePHIs, "Number of normalizable PHIs");
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STATISTIC(NumPHINormialization, "Number of PHI executed normalizations");
166
167
using namespace polly;
168
using namespace llvm;
169
170
static isl::union_map computeReachingDefinition(isl::union_map Schedule,
171
                                                isl::union_map Writes,
172
152
                                                bool InclDef, bool InclRedef) {
173
152
  return computeReachingWrite(Schedule, Writes, false, InclDef, InclRedef);
174
152
}
175
176
/// Compute the reaching definition of a scalar.
177
///
178
/// Compared to computeReachingDefinition, there is just one element which is
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/// accessed and therefore only a set if instances that accesses that element is
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/// required.
181
///
182
/// @param Schedule  { DomainWrite[] -> Scatter[] }
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/// @param Writes    { DomainWrite[] }
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/// @param InclDef   Include the timepoint of the definition to the result.
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/// @param InclRedef Include the timepoint of the overwrite into the result.
186
///
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/// @return { Scatter[] -> DomainWrite[] }
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static isl::union_map computeScalarReachingDefinition(isl::union_map Schedule,
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                                                      isl::union_set Writes,
190
                                                      bool InclDef,
191
67
                                                      bool InclRedef) {
192
67
  // { DomainWrite[] -> Element[] }
193
67
  isl::union_map Defs = isl::union_map::from_domain(Writes);
194
67
195
67
  // { [Element[] -> Scatter[]] -> DomainWrite[] }
196
67
  auto ReachDefs =
197
67
      computeReachingDefinition(Schedule, Defs, InclDef, InclRedef);
198
67
199
67
  // { Scatter[] -> DomainWrite[] }
200
67
  return ReachDefs.curry().range().unwrap();
201
67
}
202
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/// Compute the reaching definition of a scalar.
204
///
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/// This overload accepts only a single writing statement as an isl_map,
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/// consequently the result also is only a single isl_map.
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///
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/// @param Schedule  { DomainWrite[] -> Scatter[] }
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/// @param Writes    { DomainWrite[] }
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/// @param InclDef   Include the timepoint of the definition to the result.
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/// @param InclRedef Include the timepoint of the overwrite into the result.
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///
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/// @return { Scatter[] -> DomainWrite[] }
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static isl::map computeScalarReachingDefinition(isl::union_map Schedule,
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                                                isl::set Writes, bool InclDef,
216
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                                                bool InclRedef) {
217
67
  isl::space DomainSpace = Writes.get_space();
218
67
  isl::space ScatterSpace = getScatterSpace(Schedule);
219
67
220
67
  //  { Scatter[] -> DomainWrite[] }
221
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  isl::union_map UMap = computeScalarReachingDefinition(
222
67
      Schedule, isl::union_set(Writes), InclDef, InclRedef);
223
67
224
67
  isl::space ResultSpace = ScatterSpace.map_from_domain_and_range(DomainSpace);
225
67
  return singleton(UMap, ResultSpace);
226
67
}
227
228
642
isl::union_map polly::makeUnknownForDomain(isl::union_set Domain) {
229
642
  return isl::union_map::from_domain(Domain);
230
642
}
231
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/// Create a domain-to-unknown value mapping.
233
///
234
/// @see makeUnknownForDomain(isl::union_set)
235
///
236
/// @param Domain { Domain[] }
237
///
238
/// @return { Domain[] -> ValInst[] }
239
16
static isl::map makeUnknownForDomain(isl::set Domain) {
240
16
  return isl::map::from_domain(Domain);
241
16
}
242
243
/// Return whether @p Map maps to an unknown value.
244
///
245
/// @param { [] -> ValInst[] }
246
668
static bool isMapToUnknown(const isl::map &Map) {
247
668
  isl::space Space = Map.get_space().range();
248
668
  return Space.has_tuple_id(isl::dim::set).is_false() &&
249
668
         
Space.is_wrapping().is_false()486
&&
Space.dim(isl::dim::set) == 089
;
250
668
}
251
252
630
isl::union_map polly::filterKnownValInst(const isl::union_map &UMap) {
253
630
  isl::union_map Result = isl::union_map::empty(UMap.get_space());
254
668
  for (isl::map Map : UMap.get_map_list()) {
255
668
    if (!isMapToUnknown(Map))
256
579
      Result = Result.add_map(Map);
257
668
  }
258
630
  return Result;
259
630
}
260
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ZoneAlgorithm::ZoneAlgorithm(const char *PassName, Scop *S, LoopInfo *LI)
262
    : PassName(PassName), IslCtx(S->getSharedIslCtx()), S(S), LI(LI),
263
85
      Schedule(S->getSchedule()) {
264
85
  auto Domains = S->getDomains();
265
85
266
85
  Schedule = Schedule.intersect_domain(Domains);
267
85
  ParamSpace = Schedule.get_space();
268
85
  ScatterSpace = getScatterSpace(Schedule);
269
85
}
270
271
/// Check if all stores in @p Stmt store the very same value.
272
///
273
/// This covers a special situation occurring in Polybench's
274
/// covariance/correlation (which is typical for algorithms that cover symmetric
275
/// matrices):
276
///
277
/// for (int i = 0; i < n; i += 1)
278
///   for (int j = 0; j <= i; j += 1) {
279
///     double x = ...;
280
///     C[i][j] = x;
281
///     C[j][i] = x;
282
///   }
283
///
284
/// For i == j, the same value is written twice to the same element.Double
285
/// writes to the same element are not allowed in DeLICM because its algorithm
286
/// does not see which of the writes is effective.But if its the same value
287
/// anyway, it doesn't matter.
288
///
289
/// LLVM passes, however, cannot simplify this because the write is necessary
290
/// for i != j (unless it would add a condition for one of the writes to occur
291
/// only if i != j).
292
///
293
/// TODO: In the future we may want to extent this to make the checks
294
///       specific to different memory locations.
295
5
static bool onlySameValueWrites(ScopStmt *Stmt) {
296
5
  Value *V = nullptr;
297
5
298
16
  for (auto *MA : *Stmt) {
299
16
    if (!MA->isLatestArrayKind() || 
!MA->isMustWrite()10
||
300
16
        
!MA->isOriginalArrayKind()8
)
301
8
      continue;
302
8
303
8
    if (!V) {
304
4
      V = MA->getAccessValue();
305
4
      continue;
306
4
    }
307
4
308
4
    if (V != MA->getAccessValue())
309
2
      return false;
310
4
  }
311
5
  
return true3
;
312
5
}
313
314
/// Is @p InnerLoop nested inside @p OuterLoop?
315
62
static bool isInsideLoop(Loop *OuterLoop, Loop *InnerLoop) {
316
62
  // If OuterLoop is nullptr, we cannot call its contains() method. In this case
317
62
  // OuterLoop represents the 'top level' and therefore contains all loop.
318
62
  return !OuterLoop || 
OuterLoop->contains(InnerLoop)61
;
319
62
}
320
321
void ZoneAlgorithm::collectIncompatibleElts(ScopStmt *Stmt,
322
                                            isl::union_set &IncompatibleElts,
323
337
                                            isl::union_set &AllElts) {
324
337
  auto Stores = makeEmptyUnionMap();
325
337
  auto Loads = makeEmptyUnionMap();
326
337
327
337
  // This assumes that the MemoryKind::Array MemoryAccesses are iterated in
328
337
  // order.
329
674
  for (auto *MA : *Stmt) {
330
674
    if (!MA->isOriginalArrayKind())
331
492
      continue;
332
182
333
182
    isl::map AccRelMap = getAccessRelationFor(MA);
334
182
    isl::union_map AccRel = AccRelMap;
335
182
336
182
    // To avoid solving any ILP problems, always add entire arrays instead of
337
182
    // just the elements that are accessed.
338
182
    auto ArrayElts = isl::set::universe(AccRelMap.get_space().range());
339
182
    AllElts = AllElts.add_set(ArrayElts);
340
182
341
182
    if (MA->isRead()) {
342
58
      // Reject load after store to same location.
343
58
      if (!Stores.is_disjoint(AccRel)) {
344
1
        LLVM_DEBUG(
345
1
            dbgs() << "Load after store of same element in same statement\n");
346
1
        OptimizationRemarkMissed R(PassName, "LoadAfterStore",
347
1
                                   MA->getAccessInstruction());
348
1
        R << "load after store of same element in same statement";
349
1
        R << " (previous stores: " << Stores;
350
1
        R << ", loading: " << AccRel << ")";
351
1
        S->getFunction().getContext().diagnose(R);
352
1
353
1
        IncompatibleElts = IncompatibleElts.add_set(ArrayElts);
354
1
      }
355
58
356
58
      Loads = Loads.unite(AccRel);
357
58
358
58
      continue;
359
58
    }
360
124
361
124
    // In region statements the order is less clear, eg. the load and store
362
124
    // might be in a boxed loop.
363
124
    if (Stmt->isRegionStmt() && 
!Loads.is_disjoint(AccRel)9
) {
364
2
      LLVM_DEBUG(dbgs() << "WRITE in non-affine subregion not supported\n");
365
2
      OptimizationRemarkMissed R(PassName, "StoreInSubregion",
366
2
                                 MA->getAccessInstruction());
367
2
      R << "store is in a non-affine subregion";
368
2
      S->getFunction().getContext().diagnose(R);
369
2
370
2
      IncompatibleElts = IncompatibleElts.add_set(ArrayElts);
371
2
    }
372
124
373
124
    // Do not allow more than one store to the same location.
374
124
    if (!Stores.is_disjoint(AccRel) && 
!onlySameValueWrites(Stmt)5
) {
375
2
      LLVM_DEBUG(dbgs() << "WRITE after WRITE to same element\n");
376
2
      OptimizationRemarkMissed R(PassName, "StoreAfterStore",
377
2
                                 MA->getAccessInstruction());
378
2
      R << "store after store of same element in same statement";
379
2
      R << " (previous stores: " << Stores;
380
2
      R << ", storing: " << AccRel << ")";
381
2
      S->getFunction().getContext().diagnose(R);
382
2
383
2
      IncompatibleElts = IncompatibleElts.add_set(ArrayElts);
384
2
    }
385
124
386
124
    Stores = Stores.unite(AccRel);
387
124
  }
388
337
}
389
390
60
void ZoneAlgorithm::addArrayReadAccess(MemoryAccess *MA) {
391
60
  assert(MA->isLatestArrayKind());
392
60
  assert(MA->isRead());
393
60
  ScopStmt *Stmt = MA->getStatement();
394
60
395
60
  // { DomainRead[] -> Element[] }
396
60
  auto AccRel = intersectRange(getAccessRelationFor(MA), CompatibleElts);
397
60
  AllReads = AllReads.add_map(AccRel);
398
60
399
60
  if (LoadInst *Load = dyn_cast_or_null<LoadInst>(MA->getAccessInstruction())) {
400
58
    // { DomainRead[] -> ValInst[] }
401
58
    isl::map LoadValInst = makeValInst(
402
58
        Load, Stmt, LI->getLoopFor(Load->getParent()), Stmt->isBlockStmt());
403
58
404
58
    // { DomainRead[] -> [Element[] -> DomainRead[]] }
405
58
    isl::map IncludeElement = AccRel.domain_map().curry();
406
58
407
58
    // { [Element[] -> DomainRead[]] -> ValInst[] }
408
58
    isl::map EltLoadValInst = LoadValInst.apply_domain(IncludeElement);
409
58
410
58
    AllReadValInst = AllReadValInst.add_map(EltLoadValInst);
411
58
  }
412
60
}
413
414
isl::union_map ZoneAlgorithm::getWrittenValue(MemoryAccess *MA,
415
124
                                              isl::map AccRel) {
416
124
  if (!MA->isMustWrite())
417
9
    return {};
418
115
419
115
  Value *AccVal = MA->getAccessValue();
420
115
  ScopStmt *Stmt = MA->getStatement();
421
115
  Instruction *AccInst = MA->getAccessInstruction();
422
115
423
115
  // Write a value to a single element.
424
115
  auto L = MA->isOriginalArrayKind() ? LI->getLoopFor(AccInst->getParent())
425
115
                                     : 
Stmt->getSurroundingLoop()0
;
426
115
  if (AccVal &&
427
115
      
AccVal->getType() == MA->getLatestScopArrayInfo()->getElementType()109
&&
428
115
      
AccRel.is_single_valued().is_true()106
)
429
104
    return makeNormalizedValInst(AccVal, Stmt, L);
430
11
431
11
  // memset(_, '0', ) is equivalent to writing the null value to all touched
432
11
  // elements. isMustWrite() ensures that all of an element's bytes are
433
11
  // overwritten.
434
11
  if (auto *Memset = dyn_cast<MemSetInst>(AccInst)) {
435
6
    auto *WrittenConstant = dyn_cast<Constant>(Memset->getValue());
436
6
    Type *Ty = MA->getLatestScopArrayInfo()->getElementType();
437
6
    if (WrittenConstant && WrittenConstant->isZeroValue()) {
438
6
      Constant *Zero = Constant::getNullValue(Ty);
439
6
      return makeNormalizedValInst(Zero, Stmt, L);
440
6
    }
441
5
  }
442
5
443
5
  return {};
444
5
}
445
446
124
void ZoneAlgorithm::addArrayWriteAccess(MemoryAccess *MA) {
447
124
  assert(MA->isLatestArrayKind());
448
124
  assert(MA->isWrite());
449
124
  auto *Stmt = MA->getStatement();
450
124
451
124
  // { Domain[] -> Element[] }
452
124
  isl::map AccRel = intersectRange(getAccessRelationFor(MA), CompatibleElts);
453
124
454
124
  if (MA->isMustWrite())
455
115
    AllMustWrites = AllMustWrites.add_map(AccRel);
456
124
457
124
  if (MA->isMayWrite())
458
9
    AllMayWrites = AllMayWrites.add_map(AccRel);
459
124
460
124
  // { Domain[] -> ValInst[] }
461
124
  isl::union_map WriteValInstance = getWrittenValue(MA, AccRel);
462
124
  if (!WriteValInstance)
463
14
    WriteValInstance = makeUnknownForDomain(Stmt);
464
124
465
124
  // { Domain[] -> [Element[] -> Domain[]] }
466
124
  isl::map IncludeElement = AccRel.domain_map().curry();
467
124
468
124
  // { [Element[] -> DomainWrite[]] -> ValInst[] }
469
124
  isl::union_map EltWriteValInst =
470
124
      WriteValInstance.apply_domain(IncludeElement);
471
124
472
124
  AllWriteValInst = AllWriteValInst.unite(EltWriteValInst);
473
124
}
474
475
/// For an llvm::Value defined in @p DefStmt, compute the RAW dependency for a
476
/// use in every instance of @p UseStmt.
477
///
478
/// @param UseStmt Statement a scalar is used in.
479
/// @param DefStmt Statement a scalar is defined in.
480
///
481
/// @return { DomainUse[] -> DomainDef[] }
482
isl::map ZoneAlgorithm::computeUseToDefFlowDependency(ScopStmt *UseStmt,
483
45
                                                      ScopStmt *DefStmt) {
484
45
  // { DomainUse[] -> Scatter[] }
485
45
  isl::map UseScatter = getScatterFor(UseStmt);
486
45
487
45
  // { Zone[] -> DomainDef[] }
488
45
  isl::map ReachDefZone = getScalarReachingDefinition(DefStmt);
489
45
490
45
  // { Scatter[] -> DomainDef[] }
491
45
  isl::map ReachDefTimepoints =
492
45
      convertZoneToTimepoints(ReachDefZone, isl::dim::in, false, true);
493
45
494
45
  // { DomainUse[] -> DomainDef[] }
495
45
  return UseScatter.apply_range(ReachDefTimepoints);
496
45
}
497
498
/// Return whether @p PHI refers (also transitively through other PHIs) to
499
/// itself.
500
///
501
/// loop:
502
///   %phi1 = phi [0, %preheader], [%phi1, %loop]
503
///   br i1 %c, label %loop, label %exit
504
///
505
/// exit:
506
///   %phi2 = phi [%phi1, %bb]
507
///
508
/// In this example, %phi1 is recursive, but %phi2 is not.
509
6
static bool isRecursivePHI(const PHINode *PHI) {
510
6
  SmallVector<const PHINode *, 8> Worklist;
511
6
  SmallPtrSet<const PHINode *, 8> Visited;
512
6
  Worklist.push_back(PHI);
513
6
514
12
  while (!Worklist.empty()) {
515
7
    const PHINode *Cur = Worklist.pop_back_val();
516
7
517
7
    if (Visited.count(Cur))
518
0
      continue;
519
7
    Visited.insert(Cur);
520
7
521
13
    for (const Use &Incoming : Cur->incoming_values()) {
522
13
      Value *IncomingVal = Incoming.get();
523
13
      auto *IncomingPHI = dyn_cast<PHINode>(IncomingVal);
524
13
      if (!IncomingPHI)
525
11
        continue;
526
2
527
2
      if (IncomingPHI == PHI)
528
1
        return true;
529
1
      Worklist.push_back(IncomingPHI);
530
1
    }
531
7
  }
532
6
  
return false5
;
533
6
}
534
535
39
isl::union_map ZoneAlgorithm::computePerPHI(const ScopArrayInfo *SAI) {
536
39
  // TODO: If the PHI has an incoming block from before the SCoP, it is not
537
39
  // represented in any ScopStmt.
538
39
539
39
  auto *PHI = cast<PHINode>(SAI->getBasePtr());
540
39
  auto It = PerPHIMaps.find(PHI);
541
39
  if (It != PerPHIMaps.end())
542
0
    return It->second;
543
39
544
39
  assert(SAI->isPHIKind());
545
39
546
39
  // { DomainPHIWrite[] -> Scatter[] }
547
39
  isl::union_map PHIWriteScatter = makeEmptyUnionMap();
548
39
549
39
  // Collect all incoming block timepoints.
550
77
  for (MemoryAccess *MA : S->getPHIIncomings(SAI)) {
551
77
    isl::map Scatter = getScatterFor(MA);
552
77
    PHIWriteScatter = PHIWriteScatter.add_map(Scatter);
553
77
  }
554
39
555
39
  // { DomainPHIRead[] -> Scatter[] }
556
39
  isl::map PHIReadScatter = getScatterFor(S->getPHIRead(SAI));
557
39
558
39
  // { DomainPHIRead[] -> Scatter[] }
559
39
  isl::map BeforeRead = beforeScatter(PHIReadScatter, true);
560
39
561
39
  // { Scatter[] }
562
39
  isl::set WriteTimes = singleton(PHIWriteScatter.range(), ScatterSpace);
563
39
564
39
  // { DomainPHIRead[] -> Scatter[] }
565
39
  isl::map PHIWriteTimes = BeforeRead.intersect_range(WriteTimes);
566
39
  isl::map LastPerPHIWrites = PHIWriteTimes.lexmax();
567
39
568
39
  // { DomainPHIRead[] -> DomainPHIWrite[] }
569
39
  isl::union_map Result =
570
39
      isl::union_map(LastPerPHIWrites).apply_range(PHIWriteScatter.reverse());
571
39
  assert(!Result.is_single_valued().is_false());
572
39
  assert(!Result.is_injective().is_false());
573
39
574
39
  PerPHIMaps.insert({PHI, Result});
575
39
  return Result;
576
39
}
577
578
226
isl::union_set ZoneAlgorithm::makeEmptyUnionSet() const {
579
226
  return isl::union_set::empty(ParamSpace);
580
226
}
581
582
1.35k
isl::union_map ZoneAlgorithm::makeEmptyUnionMap() const {
583
1.35k
  return isl::union_map::empty(ParamSpace);
584
1.35k
}
585
586
85
void ZoneAlgorithm::collectCompatibleElts() {
587
85
  // First find all the incompatible elements, then take the complement.
588
85
  // We compile the list of compatible (rather than incompatible) elements so
589
85
  // users can intersect with the list, not requiring a subtract operation. It
590
85
  // also allows us to define a 'universe' of all elements and makes it more
591
85
  // explicit in which array elements can be used.
592
85
  isl::union_set AllElts = makeEmptyUnionSet();
593
85
  isl::union_set IncompatibleElts = makeEmptyUnionSet();
594
85
595
85
  for (auto &Stmt : *S)
596
337
    collectIncompatibleElts(&Stmt, IncompatibleElts, AllElts);
597
85
598
85
  NumIncompatibleArrays += isl_union_set_n_set(IncompatibleElts.get());
599
85
  CompatibleElts = AllElts.subtract(IncompatibleElts);
600
85
  NumCompatibleArrays += isl_union_set_n_set(CompatibleElts.get());
601
85
}
602
603
253
isl::map ZoneAlgorithm::getScatterFor(ScopStmt *Stmt) const {
604
253
  isl::space ResultSpace =
605
253
      Stmt->getDomainSpace().map_from_domain_and_range(ScatterSpace);
606
253
  return Schedule.extract_map(ResultSpace);
607
253
}
608
609
208
isl::map ZoneAlgorithm::getScatterFor(MemoryAccess *MA) const {
610
208
  return getScatterFor(MA->getStatement());
611
208
}
612
613
177
isl::union_map ZoneAlgorithm::getScatterFor(isl::union_set Domain) const {
614
177
  return Schedule.intersect_domain(Domain);
615
177
}
616
617
56
isl::map ZoneAlgorithm::getScatterFor(isl::set Domain) const {
618
56
  auto ResultSpace = Domain.get_space().map_from_domain_and_range(ScatterSpace);
619
56
  auto UDomain = isl::union_set(Domain);
620
56
  auto UResult = getScatterFor(std::move(UDomain));
621
56
  auto Result = singleton(std::move(UResult), std::move(ResultSpace));
622
56
  assert(!Result || Result.domain().is_equal(Domain) == isl_bool_true);
623
56
  return Result;
624
56
}
625
626
1.59k
isl::set ZoneAlgorithm::getDomainFor(ScopStmt *Stmt) const {
627
1.59k
  return Stmt->getDomain().remove_redundancies();
628
1.59k
}
629
630
894
isl::set ZoneAlgorithm::getDomainFor(MemoryAccess *MA) const {
631
894
  return getDomainFor(MA->getStatement());
632
894
}
633
634
464
isl::map ZoneAlgorithm::getAccessRelationFor(MemoryAccess *MA) const {
635
464
  auto Domain = getDomainFor(MA);
636
464
  auto AccRel = MA->getLatestAccessRelation();
637
464
  return AccRel.intersect_domain(Domain);
638
464
}
639
640
isl::map ZoneAlgorithm::getDefToTarget(ScopStmt *DefStmt,
641
211
                                       ScopStmt *TargetStmt) {
642
211
  // No translation required if the definition is already at the target.
643
211
  if (TargetStmt == DefStmt)
644
53
    return isl::map::identity(
645
53
        getDomainFor(TargetStmt).get_space().map_from_set());
646
158
647
158
  isl::map &Result = DefToTargetCache[std::make_pair(TargetStmt, DefStmt)];
648
158
649
158
  // This is a shortcut in case the schedule is still the original and
650
158
  // TargetStmt is in the same or nested inside DefStmt's loop. With the
651
158
  // additional assumption that operand trees do not cross DefStmt's loop
652
158
  // header, then TargetStmt's instance shared coordinates are the same as
653
158
  // DefStmt's coordinates. All TargetStmt instances with this prefix share
654
158
  // the same DefStmt instance.
655
158
  // Model:
656
158
  //
657
158
  //   for (int i < 0; i < N; i+=1) {
658
158
  // DefStmt:
659
158
  //    D = ...;
660
158
  //    for (int j < 0; j < N; j+=1) {
661
158
  // TargetStmt:
662
158
  //      use(D);
663
158
  //    }
664
158
  //  }
665
158
  //
666
158
  // Here, the value used in TargetStmt is defined in the corresponding
667
158
  // DefStmt, i.e.
668
158
  //
669
158
  //   { DefStmt[i] -> TargetStmt[i,j] }
670
158
  //
671
158
  // In practice, this should cover the majority of cases.
672
158
  if (!Result && 
S->isOriginalSchedule()89
&&
673
158
      isInsideLoop(DefStmt->getSurroundingLoop(),
674
62
                   TargetStmt->getSurroundingLoop())) {
675
44
    isl::set DefDomain = getDomainFor(DefStmt);
676
44
    isl::set TargetDomain = getDomainFor(TargetStmt);
677
44
    assert(DefDomain.dim(isl::dim::set) <= TargetDomain.dim(isl::dim::set));
678
44
679
44
    Result = isl::map::from_domain_and_range(DefDomain, TargetDomain);
680
95
    for (unsigned i = 0, DefDims = DefDomain.dim(isl::dim::set); i < DefDims;
681
51
         i += 1)
682
51
      Result = Result.equate(isl::dim::in, i, isl::dim::out, i);
683
44
  }
684
158
685
158
  if (!Result) {
686
45
    // { DomainDef[] -> DomainTarget[] }
687
45
    Result = computeUseToDefFlowDependency(TargetStmt, DefStmt).reverse();
688
45
    simplify(Result);
689
45
  }
690
158
691
158
  return Result;
692
158
}
693
694
101
isl::map ZoneAlgorithm::getScalarReachingDefinition(ScopStmt *Stmt) {
695
101
  auto &Result = ScalarReachDefZone[Stmt];
696
101
  if (Result)
697
34
    return Result;
698
67
699
67
  auto Domain = getDomainFor(Stmt);
700
67
  Result = computeScalarReachingDefinition(Schedule, Domain, false, true);
701
67
  simplify(Result);
702
67
703
67
  return Result;
704
67
}
705
706
0
isl::map ZoneAlgorithm::getScalarReachingDefinition(isl::set DomainDef) {
707
0
  auto DomId = DomainDef.get_tuple_id();
708
0
  auto *Stmt = static_cast<ScopStmt *>(isl_id_get_user(DomId.get()));
709
0
710
0
  auto StmtResult = getScalarReachingDefinition(Stmt);
711
0
712
0
  return StmtResult.intersect_range(DomainDef);
713
0
}
714
715
16
isl::map ZoneAlgorithm::makeUnknownForDomain(ScopStmt *Stmt) const {
716
16
  return ::makeUnknownForDomain(getDomainFor(Stmt));
717
16
}
718
719
364
isl::id ZoneAlgorithm::makeValueId(Value *V) {
720
364
  if (!V)
721
0
    return nullptr;
722
364
723
364
  auto &Id = ValueIds[V];
724
364
  if (Id.is_null()) {
725
198
    auto Name = getIslCompatibleName("Val_", V, ValueIds.size() - 1,
726
198
                                     std::string(), UseInstructionNames);
727
198
    Id = isl::id::alloc(IslCtx.get(), Name.c_str(), V);
728
198
  }
729
364
  return Id;
730
364
}
731
732
364
isl::space ZoneAlgorithm::makeValueSpace(Value *V) {
733
364
  auto Result = ParamSpace.set_from_params();
734
364
  return Result.set_tuple_id(isl::dim::set, makeValueId(V));
735
364
}
736
737
364
isl::set ZoneAlgorithm::makeValueSet(Value *V) {
738
364
  auto Space = makeValueSpace(V);
739
364
  return isl::set::universe(Space);
740
364
}
741
742
isl::map ZoneAlgorithm::makeValInst(Value *Val, ScopStmt *UserStmt, Loop *Scope,
743
369
                                    bool IsCertain) {
744
369
  // If the definition/write is conditional, the value at the location could
745
369
  // be either the written value or the old value. Since we cannot know which
746
369
  // one, consider the value to be unknown.
747
369
  if (!IsCertain)
748
2
    return makeUnknownForDomain(UserStmt);
749
367
750
367
  auto DomainUse = getDomainFor(UserStmt);
751
367
  auto VUse = VirtualUse::create(S, UserStmt, Scope, Val, true);
752
367
  switch (VUse.getKind()) {
753
367
  case VirtualUse::Constant:
754
48
  case VirtualUse::Block:
755
48
  case VirtualUse::Hoisted:
756
48
  case VirtualUse::ReadOnly: {
757
48
    // The definition does not depend on the statement which uses it.
758
48
    auto ValSet = makeValueSet(Val);
759
48
    return isl::map::from_domain_and_range(DomainUse, ValSet);
760
48
  }
761
48
762
48
  case VirtualUse::Synthesizable: {
763
3
    auto *ScevExpr = VUse.getScevExpr();
764
3
    auto UseDomainSpace = DomainUse.get_space();
765
3
766
3
    // Construct the SCEV space.
767
3
    // TODO: Add only the induction variables referenced in SCEVAddRecExpr
768
3
    // expressions, not just all of them.
769
3
    auto ScevId = isl::manage(isl_id_alloc(
770
3
        UseDomainSpace.get_ctx().get(), nullptr, const_cast<SCEV *>(ScevExpr)));
771
3
772
3
    auto ScevSpace = UseDomainSpace.drop_dims(isl::dim::set, 0, 0);
773
3
    ScevSpace = ScevSpace.set_tuple_id(isl::dim::set, ScevId);
774
3
775
3
    // { DomainUse[] -> ScevExpr[] }
776
3
    auto ValInst =
777
3
        isl::map::identity(UseDomainSpace.map_from_domain_and_range(ScevSpace));
778
3
    return ValInst;
779
48
  }
780
48
781
186
  case VirtualUse::Intra: {
782
186
    // Definition and use is in the same statement. We do not need to compute
783
186
    // a reaching definition.
784
186
785
186
    // { llvm::Value }
786
186
    auto ValSet = makeValueSet(Val);
787
186
788
186
    // {  UserDomain[] -> llvm::Value }
789
186
    auto ValInstSet = isl::map::from_domain_and_range(DomainUse, ValSet);
790
186
791
186
    // { UserDomain[] -> [UserDomain[] - >llvm::Value] }
792
186
    auto Result = ValInstSet.domain_map().reverse();
793
186
    simplify(Result);
794
186
    return Result;
795
48
  }
796
48
797
130
  case VirtualUse::Inter: {
798
130
    // The value is defined in a different statement.
799
130
800
130
    auto *Inst = cast<Instruction>(Val);
801
130
    auto *ValStmt = S->getStmtFor(Inst);
802
130
803
130
    // If the llvm::Value is defined in a removed Stmt, we cannot derive its
804
130
    // domain. We could use an arbitrary statement, but this could result in
805
130
    // different ValInst[] for the same llvm::Value.
806
130
    if (!ValStmt)
807
0
      return ::makeUnknownForDomain(DomainUse);
808
130
809
130
    // { DomainUse[] -> DomainDef[] }
810
130
    auto UsedInstance = getDefToTarget(ValStmt, UserStmt).reverse();
811
130
812
130
    // { llvm::Value }
813
130
    auto ValSet = makeValueSet(Val);
814
130
815
130
    // { DomainUse[] -> llvm::Value[] }
816
130
    auto ValInstSet = isl::map::from_domain_and_range(DomainUse, ValSet);
817
130
818
130
    // { DomainUse[] -> [DomainDef[] -> llvm::Value]  }
819
130
    auto Result = UsedInstance.range_product(ValInstSet);
820
130
821
130
    simplify(Result);
822
130
    return Result;
823
130
  }
824
0
  }
825
0
  llvm_unreachable("Unhandled use type");
826
0
}
827
828
/// Remove all computed PHIs out of @p Input and replace by their incoming
829
/// value.
830
///
831
/// @param Input        { [] -> ValInst[] }
832
/// @param ComputedPHIs Set of PHIs that are replaced. Its ValInst must appear
833
///                     on the LHS of @p NormalizeMap.
834
/// @param NormalizeMap { ValInst[] -> ValInst[] }
835
static isl::union_map normalizeValInst(isl::union_map Input,
836
                                       const DenseSet<PHINode *> &ComputedPHIs,
837
144
                                       isl::union_map NormalizeMap) {
838
144
  isl::union_map Result = isl::union_map::empty(Input.get_space());
839
147
  for (isl::map Map : Input.get_map_list()) {
840
147
    isl::space Space = Map.get_space();
841
147
    isl::space RangeSpace = Space.range();
842
147
843
147
    // Instructions within the SCoP are always wrapped. Non-wrapped tuples
844
147
    // are therefore invariant in the SCoP and don't need normalization.
845
147
    if (!RangeSpace.is_wrapping()) {
846
27
      Result = Result.add_map(Map);
847
27
      continue;
848
27
    }
849
120
850
120
    auto *PHI = dyn_cast<PHINode>(static_cast<Value *>(
851
120
        RangeSpace.unwrap().get_tuple_id(isl::dim::out).get_user()));
852
120
853
120
    // If no normalization is necessary, then the ValInst stands for itself.
854
120
    if (!ComputedPHIs.count(PHI)) {
855
106
      Result = Result.add_map(Map);
856
106
      continue;
857
106
    }
858
14
859
14
    // Otherwise, apply the normalization.
860
14
    isl::union_map Mapped = isl::union_map(Map).apply_range(NormalizeMap);
861
14
    Result = Result.unite(Mapped);
862
14
    NumPHINormialization++;
863
14
  }
864
144
  return Result;
865
144
}
866
867
isl::union_map ZoneAlgorithm::makeNormalizedValInst(llvm::Value *Val,
868
                                                    ScopStmt *UserStmt,
869
                                                    llvm::Loop *Scope,
870
134
                                                    bool IsCertain) {
871
134
  isl::map ValInst = makeValInst(Val, UserStmt, Scope, IsCertain);
872
134
  isl::union_map Normalized =
873
134
      normalizeValInst(ValInst, ComputedPHIs, NormalizeMap);
874
134
  return Normalized;
875
134
}
876
877
0
bool ZoneAlgorithm::isCompatibleAccess(MemoryAccess *MA) {
878
0
  if (!MA)
879
0
    return false;
880
0
  if (!MA->isLatestArrayKind())
881
0
    return false;
882
0
  Instruction *AccInst = MA->getAccessInstruction();
883
0
  return isa<StoreInst>(AccInst) || isa<LoadInst>(AccInst);
884
0
}
885
886
6
bool ZoneAlgorithm::isNormalizable(MemoryAccess *MA) {
887
6
  assert(MA->isRead());
888
6
889
6
  // Exclude ExitPHIs, we are assuming that a normalizable PHI has a READ
890
6
  // MemoryAccess.
891
6
  if (!MA->isOriginalPHIKind())
892
0
    return false;
893
6
894
6
  // Exclude recursive PHIs, normalizing them would require a transitive
895
6
  // closure.
896
6
  auto *PHI = cast<PHINode>(MA->getAccessInstruction());
897
6
  if (RecursivePHIs.count(PHI))
898
1
    return false;
899
5
900
5
  // Ensure that each incoming value can be represented by a ValInst[].
901
5
  // We do represent values from statements associated to multiple incoming
902
5
  // value by the PHI itself, but we do not handle this case yet (especially
903
5
  // isNormalized()) when normalizing.
904
5
  const ScopArrayInfo *SAI = MA->getOriginalScopArrayInfo();
905
5
  auto Incomings = S->getPHIIncomings(SAI);
906
9
  for (MemoryAccess *Incoming : Incomings) {
907
9
    if (Incoming->getIncoming().size() != 1)
908
0
      return false;
909
9
  }
910
5
911
5
  return true;
912
5
}
913
914
0
isl::boolean ZoneAlgorithm::isNormalized(isl::map Map) {
915
0
  isl::space Space = Map.get_space();
916
0
  isl::space RangeSpace = Space.range();
917
0
918
0
  isl::boolean IsWrapping = RangeSpace.is_wrapping();
919
0
  if (!IsWrapping.is_true())
920
0
    return !IsWrapping;
921
0
  isl::space Unwrapped = RangeSpace.unwrap();
922
0
923
0
  isl::id OutTupleId = Unwrapped.get_tuple_id(isl::dim::out);
924
0
  if (OutTupleId.is_null())
925
0
    return isl::boolean();
926
0
  auto *PHI = dyn_cast<PHINode>(static_cast<Value *>(OutTupleId.get_user()));
927
0
  if (!PHI)
928
0
    return true;
929
0
930
0
  isl::id InTupleId = Unwrapped.get_tuple_id(isl::dim::in);
931
0
  if (OutTupleId.is_null())
932
0
    return isl::boolean();
933
0
  auto *IncomingStmt = static_cast<ScopStmt *>(InTupleId.get_user());
934
0
  MemoryAccess *PHIRead = IncomingStmt->lookupPHIReadOf(PHI);
935
0
  if (!isNormalizable(PHIRead))
936
0
    return true;
937
0
938
0
  return false;
939
0
}
940
941
0
isl::boolean ZoneAlgorithm::isNormalized(isl::union_map UMap) {
942
0
  isl::boolean Result = true;
943
0
  for (isl::map Map : UMap.get_map_list()) {
944
0
    Result = isNormalized(Map);
945
0
    if (Result.is_true())
946
0
      continue;
947
0
    break;
948
0
  }
949
0
  return Result;
950
0
}
951
952
85
void ZoneAlgorithm::computeCommon() {
953
85
  AllReads = makeEmptyUnionMap();
954
85
  AllMayWrites = makeEmptyUnionMap();
955
85
  AllMustWrites = makeEmptyUnionMap();
956
85
  AllWriteValInst = makeEmptyUnionMap();
957
85
  AllReadValInst = makeEmptyUnionMap();
958
85
959
85
  // Default to empty, i.e. no normalization/replacement is taking place. Call
960
85
  // computeNormalizedPHIs() to initialize.
961
85
  NormalizeMap = makeEmptyUnionMap();
962
85
  ComputedPHIs.clear();
963
85
964
337
  for (auto &Stmt : *S) {
965
674
    for (auto *MA : Stmt) {
966
674
      if (!MA->isLatestArrayKind())
967
490
        continue;
968
184
969
184
      if (MA->isRead())
970
60
        addArrayReadAccess(MA);
971
184
972
184
      if (MA->isWrite())
973
124
        addArrayWriteAccess(MA);
974
184
    }
975
337
  }
976
85
977
85
  // { DomainWrite[] -> Element[] }
978
85
  AllWrites = AllMustWrites.unite(AllMayWrites);
979
85
980
85
  // { [Element[] -> Zone[]] -> DomainWrite[] }
981
85
  WriteReachDefZone =
982
85
      computeReachingDefinition(Schedule, AllWrites, false, true);
983
85
  simplify(WriteReachDefZone);
984
85
}
985
986
4
void ZoneAlgorithm::computeNormalizedPHIs() {
987
4
  // Determine which PHIs can reference themselves. They are excluded from
988
4
  // normalization to avoid problems with transitive closures.
989
13
  for (ScopStmt &Stmt : *S) {
990
38
    for (MemoryAccess *MA : Stmt) {
991
38
      if (!MA->isPHIKind())
992
21
        continue;
993
17
      if (!MA->isRead())
994
11
        continue;
995
6
996
6
      // TODO: Can be more efficient since isRecursivePHI can theoretically
997
6
      // determine recursiveness for multiple values and/or cache results.
998
6
      auto *PHI = cast<PHINode>(MA->getAccessInstruction());
999
6
      if (isRecursivePHI(PHI)) {
1000
1
        NumRecursivePHIs++;
1001
1
        RecursivePHIs.insert(PHI);
1002
1
      }
1003
6
    }
1004
13
  }
1005
4
1006
4
  // { PHIValInst[] -> IncomingValInst[] }
1007
4
  isl::union_map AllPHIMaps = makeEmptyUnionMap();
1008
4
1009
4
  // Discover new PHIs and try to normalize them.
1010
4
  DenseSet<PHINode *> AllPHIs;
1011
13
  for (ScopStmt &Stmt : *S) {
1012
38
    for (MemoryAccess *MA : Stmt) {
1013
38
      if (!MA->isOriginalPHIKind())
1014
21
        continue;
1015
17
      if (!MA->isRead())
1016
11
        continue;
1017
6
      if (!isNormalizable(MA))
1018
1
        continue;
1019
5
1020
5
      auto *PHI = cast<PHINode>(MA->getAccessInstruction());
1021
5
      const ScopArrayInfo *SAI = MA->getOriginalScopArrayInfo();
1022
5
1023
5
      // { PHIDomain[] -> PHIValInst[] }
1024
5
      isl::map PHIValInst = makeValInst(PHI, &Stmt, Stmt.getSurroundingLoop());
1025
5
1026
5
      // { IncomingDomain[] -> IncomingValInst[] }
1027
5
      isl::union_map IncomingValInsts = makeEmptyUnionMap();
1028
5
1029
5
      // Get all incoming values.
1030
9
      for (MemoryAccess *MA : S->getPHIIncomings(SAI)) {
1031
9
        ScopStmt *IncomingStmt = MA->getStatement();
1032
9
1033
9
        auto Incoming = MA->getIncoming();
1034
9
        assert(Incoming.size() == 1 && "The incoming value must be "
1035
9
                                       "representable by something else than "
1036
9
                                       "the PHI itself");
1037
9
        Value *IncomingVal = Incoming[0].second;
1038
9
1039
9
        // { IncomingDomain[] -> IncomingValInst[] }
1040
9
        isl::map IncomingValInst = makeValInst(
1041
9
            IncomingVal, IncomingStmt, IncomingStmt->getSurroundingLoop());
1042
9
1043
9
        IncomingValInsts = IncomingValInsts.add_map(IncomingValInst);
1044
9
      }
1045
5
1046
5
      // Determine which instance of the PHI statement corresponds to which
1047
5
      // incoming value.
1048
5
      // { PHIDomain[] -> IncomingDomain[] }
1049
5
      isl::union_map PerPHI = computePerPHI(SAI);
1050
5
1051
5
      // { PHIValInst[] -> IncomingValInst[] }
1052
5
      isl::union_map PHIMap =
1053
5
          PerPHI.apply_domain(PHIValInst).apply_range(IncomingValInsts);
1054
5
      assert(!PHIMap.is_single_valued().is_false());
1055
5
1056
5
      // Resolve transitiveness: The incoming value of the newly discovered PHI
1057
5
      // may reference a previously normalized PHI. At the same time, already
1058
5
      // normalized PHIs might be normalized to the new PHI. At the end, none of
1059
5
      // the PHIs may appear on the right-hand-side of the normalization map.
1060
5
      PHIMap = normalizeValInst(PHIMap, AllPHIs, AllPHIMaps);
1061
5
      AllPHIs.insert(PHI);
1062
5
      AllPHIMaps = normalizeValInst(AllPHIMaps, AllPHIs, PHIMap);
1063
5
1064
5
      AllPHIMaps = AllPHIMaps.unite(PHIMap);
1065
5
      NumNormalizablePHIs++;
1066
5
    }
1067
13
  }
1068
4
  simplify(AllPHIMaps);
1069
4
1070
4
  // Apply the normalization.
1071
4
  ComputedPHIs = AllPHIs;
1072
4
  NormalizeMap = AllPHIMaps;
1073
4
1074
4
  assert(!NormalizeMap || isNormalized(NormalizeMap));
1075
4
}
1076
1077
28
void ZoneAlgorithm::printAccesses(llvm::raw_ostream &OS, int Indent) const {
1078
28
  OS.indent(Indent) << "After accesses {\n";
1079
139
  for (auto &Stmt : *S) {
1080
139
    OS.indent(Indent + 4) << Stmt.getBaseName() << "\n";
1081
139
    for (auto *MA : Stmt)
1082
278
      MA->print(OS);
1083
139
  }
1084
28
  OS.indent(Indent) << "}\n";
1085
28
}
1086
1087
85
isl::union_map ZoneAlgorithm::computeKnownFromMustWrites() const {
1088
85
  // { [Element[] -> Zone[]] -> [Element[] -> DomainWrite[]] }
1089
85
  isl::union_map EltReachdDef = distributeDomain(WriteReachDefZone.curry());
1090
85
1091
85
  // { [Element[] -> DomainWrite[]] -> ValInst[] }
1092
85
  isl::union_map AllKnownWriteValInst = filterKnownValInst(AllWriteValInst);
1093
85
1094
85
  // { [Element[] -> Zone[]] -> ValInst[] }
1095
85
  return EltReachdDef.apply_range(AllKnownWriteValInst);
1096
85
}
1097
1098
34
isl::union_map ZoneAlgorithm::computeKnownFromLoad() const {
1099
34
  // { Element[] }
1100
34
  isl::union_set AllAccessedElts = AllReads.range().unite(AllWrites.range());
1101
34
1102
34
  // { Element[] -> Scatter[] }
1103
34
  isl::union_map EltZoneUniverse = isl::union_map::from_domain_and_range(
1104
34
      AllAccessedElts, isl::set::universe(ScatterSpace));
1105
34
1106
34
  // This assumes there are no "holes" in
1107
34
  // isl_union_map_domain(WriteReachDefZone); alternatively, compute the zone
1108
34
  // before the first write or that are not written at all.
1109
34
  // { Element[] -> Scatter[] }
1110
34
  isl::union_set NonReachDef =
1111
34
      EltZoneUniverse.wrap().subtract(WriteReachDefZone.domain());
1112
34
1113
34
  // { [Element[] -> Zone[]] -> ReachDefId[] }
1114
34
  isl::union_map DefZone =
1115
34
      WriteReachDefZone.unite(isl::union_map::from_domain(NonReachDef));
1116
34
1117
34
  // { [Element[] -> Scatter[]] -> Element[] }
1118
34
  isl::union_map EltZoneElt = EltZoneUniverse.domain_map();
1119
34
1120
34
  // { [Element[] -> Zone[]] -> [Element[] -> ReachDefId[]] }
1121
34
  isl::union_map DefZoneEltDefId = EltZoneElt.range_product(DefZone);
1122
34
1123
34
  // { Element[] -> [Zone[] -> ReachDefId[]] }
1124
34
  isl::union_map EltDefZone = DefZone.curry();
1125
34
1126
34
  // { [Element[] -> Zone[] -> [Element[] -> ReachDefId[]] }
1127
34
  isl::union_map EltZoneEltDefid = distributeDomain(EltDefZone);
1128
34
1129
34
  // { [Element[] -> Scatter[]] -> DomainRead[] }
1130
34
  isl::union_map Reads = AllReads.range_product(Schedule).reverse();
1131
34
1132
34
  // { [Element[] -> Scatter[]] -> [Element[] -> DomainRead[]] }
1133
34
  isl::union_map ReadsElt = EltZoneElt.range_product(Reads);
1134
34
1135
34
  // { [Element[] -> Scatter[]] -> ValInst[] }
1136
34
  isl::union_map ScatterKnown = ReadsElt.apply_range(AllReadValInst);
1137
34
1138
34
  // { [Element[] -> ReachDefId[]] -> ValInst[] }
1139
34
  isl::union_map DefidKnown =
1140
34
      DefZoneEltDefId.apply_domain(ScatterKnown).reverse();
1141
34
1142
34
  // { [Element[] -> Zone[]] -> ValInst[] }
1143
34
  return DefZoneEltDefId.apply_range(DefidKnown);
1144
34
}
1145
1146
isl::union_map ZoneAlgorithm::computeKnown(bool FromWrite,
1147
85
                                           bool FromRead) const {
1148
85
  isl::union_map Result = makeEmptyUnionMap();
1149
85
1150
85
  if (FromWrite)
1151
85
    Result = Result.unite(computeKnownFromMustWrites());
1152
85
1153
85
  if (FromRead)
1154
34
    Result = Result.unite(computeKnownFromLoad());
1155
85
1156
85
  simplify(Result);
1157
85
  return Result;
1158
85
}