maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity
llvm-project/polly/lib/Transform/FlattenSchedule.cpp

109 lines
3.4 KiB
C++
Raw Normal View History

Add -polly-flatten-schedule pass. The -polly-flatten-schedule pass reduces the number of scattering dimensions in its isl_union_map form to make them easier to understand. It is not meant to be used in production, only for debugging and regression tests. To illustrate, how it can make sets simpler, here is a lifetime set used computed by the porposed DeLICM pass without flattening: { Stmt_reduction_for[0, 4] -> [0, 2, o2, o3] : o2 < 0; Stmt_reduction_for[0, 4] -> [0, 1, o2, o3] : o2 >= 5; Stmt_reduction_for[0, 4] -> [0, 1, 4, o3] : o3 > 0; Stmt_reduction_for[0, i1] -> [0, 1, i1, 1] : 0 <= i1 <= 3; Stmt_reduction_for[0, 4] -> [0, 2, 0, o3] : o3 <= 0 } And here the same lifetime for a semantically identical one-dimensional schedule: { Stmt_reduction_for[0, i1] -> [2 + 3i1] : 0 <= i1 <= 4 } Differential Revision: https://reviews.llvm.org/D24310 llvm-svn: 280948
2016-09-08 23:02:36 +08:00
//===------ FlattenSchedule.cpp --------------------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Try to reduce the number of scatter dimension. Useful to make isl_union_map
// schedules more understandable. This is only intended for debugging and
// unittests, not for production use.
//
//===----------------------------------------------------------------------===//
#include "polly/FlattenSchedule.h"
#include "polly/FlattenAlgo.h"
#include "polly/ScopInfo.h"
#include "polly/ScopPass.h"
[isl++] Move isl raw_ostream printers into separate header Instead of relying on these functions to be part of the isl C++ bindings, we just define this functionality independently. This allows us to use isl C++ bindings that do not contain LLVM specific functionality. llvm-svn: 303503
2017-05-21 21:16:05 +08:00
#include "polly/Support/ISLOStream.h"
Add -polly-flatten-schedule pass. The -polly-flatten-schedule pass reduces the number of scattering dimensions in its isl_union_map form to make them easier to understand. It is not meant to be used in production, only for debugging and regression tests. To illustrate, how it can make sets simpler, here is a lifetime set used computed by the porposed DeLICM pass without flattening: { Stmt_reduction_for[0, 4] -> [0, 2, o2, o3] : o2 < 0; Stmt_reduction_for[0, 4] -> [0, 1, o2, o3] : o2 >= 5; Stmt_reduction_for[0, 4] -> [0, 1, 4, o3] : o3 > 0; Stmt_reduction_for[0, i1] -> [0, 1, i1, 1] : 0 <= i1 <= 3; Stmt_reduction_for[0, 4] -> [0, 2, 0, o3] : o3 <= 0 } And here the same lifetime for a semantically identical one-dimensional schedule: { Stmt_reduction_for[0, i1] -> [2 + 3i1] : 0 <= i1 <= 4 } Differential Revision: https://reviews.llvm.org/D24310 llvm-svn: 280948
2016-09-08 23:02:36 +08:00
#define DEBUG_TYPE "polly-flatten-schedule"
using namespace polly;
using namespace llvm;
namespace {
/// Print a schedule to @p OS.
///
/// Prints the schedule for each statements on a new line.
Introduce isl C++ bindings, Part 1: value_ptr style interface Over the last couple of months several authors of independent isl C++ bindings worked together to jointly design an official set of isl C++ bindings which combines their experience in developing isl C++ bindings. The new bindings have been designed around a value pointer style interface and remove the need for explicit pointer managenent and instead use C++ language features to manage isl objects. This commit introduces the smart-pointer part of the isl C++ bindings and replaces the current IslPtr<T> classes, which served the very same purpose, but had to be manually maintained. Instead, we now rely on automatically generated classes for each isl object, which provide value_ptr semantics. An isl object has the following smart pointer interface: inline set manage(__isl_take isl_set *ptr); class set { friend inline set manage(__isl_take isl_set *ptr); isl_set *ptr = nullptr; inline explicit set(__isl_take isl_set *ptr); public: inline set(); inline set(const set &obj); inline set &operator=(set obj); inline ~set(); inline __isl_give isl_set *copy() const &; inline __isl_give isl_set *copy() && = delete; inline __isl_keep isl_set *get() const; inline __isl_give isl_set *release(); inline bool is_null() const; } The interface and behavior of the new value pointer style classes is inspired by http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3339.pdf, which proposes a std::value_ptr, a smart pointer that applies value semantics to its pointee. We currently only provide a limited set of public constructors and instead require provide a global overloaded type constructor method "isl::obj isl::manage(isl_obj *)", which allows to convert an isl_set* to an isl::set by calling 'S = isl::manage(s)'. This pattern models the make_unique() constructor for unique pointers. The next two functions isl::obj::get() and isl::obj::release() are taken directly from the std::value_ptr proposal: S.get() extracts the raw pointer of the object managed by S. S.release() extracts the raw pointer of the object managed by S and sets the object in S to null. We additionally add std::obj::copy(). S.copy() returns a raw pointer refering to a copy of S, which is a shortcut for "isl::obj(oldobj).release()", a functionality commonly needed when interacting directly with the isl C interface where all methods marked with __isl_take require consumable raw pointers. S.is_null() checks if S manages a pointer or if the managed object is currently null. We add this function to provide a more explicit way to check if the pointer is empty compared to a direct conversion to bool. This commit also introduces a couple of polly-specific extensions that cover features currently not handled by the official isl C++ bindings draft, but which have been provided by IslPtr<T> and are consequently added to avoid code churn. These extensions include: - operator bool() : Conversion from objects to bool - construction from nullptr_t - get_ctx() method - take/keep/give methods, which match the currently used naming convention of IslPtr<T> in Polly. They just forward to (release/get/manage). - raw_ostream printers We expect that these extensions are over time either removed or upstreamed to the official isl bindings. We also export a couple of classes that have not yet been exported in isl (e.g., isl::space) As part of the code review, the following two questions were asked: - Why do we not use a standard smart pointer? std::value_ptr was a proposal that has not been accepted. It is consequently not available in the standard library. Even if it would be available, we want to expand this interface with a complete method interface that is conveniently available from each managed pointer. The most direct way to achieve this is to generate a specialiced value style pointer class for each isl object type and add any additional methods to this class. The relevant changes follow in subsequent commits. - Why do we not use templates or macros to avoid code duplication? It is certainly possible to use templates or macros, but as this code is auto-generated there is no need to make writing this code more efficient. Also, most of these classes will be specialized with individual member functions in subsequent commits, such that there will be little code reuse to exploit. Hence, we decided to do so at the moment. These bindings are not yet officially part of isl, but the draft is already very stable. The smart pointer interface itself did not change since serveral months. Adding this code to Polly is against our normal policy of only importing official isl code. In this case however, we make an exception to showcase a non-trivial use case of these bindings which should increase confidence in these bindings and will help upstreaming them to isl. Tags: #polly Reviewed By: Meinersbur Differential Revision: https://reviews.llvm.org/D30325 llvm-svn: 297452
2017-03-10 19:41:03 +08:00
void printSchedule(raw_ostream &OS, const isl::union_map &Schedule,
Add -polly-flatten-schedule pass. The -polly-flatten-schedule pass reduces the number of scattering dimensions in its isl_union_map form to make them easier to understand. It is not meant to be used in production, only for debugging and regression tests. To illustrate, how it can make sets simpler, here is a lifetime set used computed by the porposed DeLICM pass without flattening: { Stmt_reduction_for[0, 4] -> [0, 2, o2, o3] : o2 < 0; Stmt_reduction_for[0, 4] -> [0, 1, o2, o3] : o2 >= 5; Stmt_reduction_for[0, 4] -> [0, 1, 4, o3] : o3 > 0; Stmt_reduction_for[0, i1] -> [0, 1, i1, 1] : 0 <= i1 <= 3; Stmt_reduction_for[0, 4] -> [0, 2, 0, o3] : o3 <= 0 } And here the same lifetime for a semantically identical one-dimensional schedule: { Stmt_reduction_for[0, i1] -> [2 + 3i1] : 0 <= i1 <= 4 } Differential Revision: https://reviews.llvm.org/D24310 llvm-svn: 280948
2016-09-08 23:02:36 +08:00
int indent) {
Use isl C++ foreach implementation This commit switches Polly over to the isl::obj::foreach_* implementation, which is part of the new isl bindings and follows the foreach pattern established in Polly by Michael Kruse. The original isl C function: isl_stat isl_union_set_foreach_set(__isl_keep isl_union_set *uset, isl_stat (*fn)(__isl_take isl_set *set, void *user), void *user); which required the user to define a static callback function to which all interesting parameters are passed via a 'void *' user-pointer, is on the C++ side available as a function that takes a std::function<>, which can carry any additional arguments without the need for a user pointer: stat UnionSet::foreach_set(const std::function<stat(set)> &fn) const; The following code illustrates the use of the new C++ interface: auto Lambda = [=, &Result](isl::set Set) -> isl::stat { auto Shifted = shiftDimension(Set, Pos, Amount); Result = Result.add(Shifted); return isl::stat::ok; } UnionSet.foreach_set(Lambda); Polly had some specialized foreach functions which did not require the lambdas to return a status flag. We remove these functions in this commit to move Polly completely over to the new isl interface. We may in the future discuss if functors without return values can be supported easily. Another extension proposed by Michael Kruse is the use of C++ iterators to allow the use of normal for loops to iterate over these sets. Such an extension would allow us to further simplify the code. Reviewed-by: Michael Kruse <llvm@meinersbur.de> Differential Revision: https://reviews.llvm.org/D30620 llvm-svn: 300323
2017-04-14 21:39:40 +08:00
Schedule.foreach_map([&OS, indent](isl::map Map) -> isl::stat {
OS.indent(indent) << Map << "\n";
return isl::stat::ok;
});
Add -polly-flatten-schedule pass. The -polly-flatten-schedule pass reduces the number of scattering dimensions in its isl_union_map form to make them easier to understand. It is not meant to be used in production, only for debugging and regression tests. To illustrate, how it can make sets simpler, here is a lifetime set used computed by the porposed DeLICM pass without flattening: { Stmt_reduction_for[0, 4] -> [0, 2, o2, o3] : o2 < 0; Stmt_reduction_for[0, 4] -> [0, 1, o2, o3] : o2 >= 5; Stmt_reduction_for[0, 4] -> [0, 1, 4, o3] : o3 > 0; Stmt_reduction_for[0, i1] -> [0, 1, i1, 1] : 0 <= i1 <= 3; Stmt_reduction_for[0, 4] -> [0, 2, 0, o3] : o3 <= 0 } And here the same lifetime for a semantically identical one-dimensional schedule: { Stmt_reduction_for[0, i1] -> [2 + 3i1] : 0 <= i1 <= 4 } Differential Revision: https://reviews.llvm.org/D24310 llvm-svn: 280948
2016-09-08 23:02:36 +08:00
}
/// Flatten the schedule stored in an polly::Scop.
class FlattenSchedule : public ScopPass {
private:
FlattenSchedule(const FlattenSchedule &) = delete;
const FlattenSchedule &operator=(const FlattenSchedule &) = delete;
std::shared_ptr<isl_ctx> IslCtx;
Introduce isl C++ bindings, Part 1: value_ptr style interface Over the last couple of months several authors of independent isl C++ bindings worked together to jointly design an official set of isl C++ bindings which combines their experience in developing isl C++ bindings. The new bindings have been designed around a value pointer style interface and remove the need for explicit pointer managenent and instead use C++ language features to manage isl objects. This commit introduces the smart-pointer part of the isl C++ bindings and replaces the current IslPtr<T> classes, which served the very same purpose, but had to be manually maintained. Instead, we now rely on automatically generated classes for each isl object, which provide value_ptr semantics. An isl object has the following smart pointer interface: inline set manage(__isl_take isl_set *ptr); class set { friend inline set manage(__isl_take isl_set *ptr); isl_set *ptr = nullptr; inline explicit set(__isl_take isl_set *ptr); public: inline set(); inline set(const set &obj); inline set &operator=(set obj); inline ~set(); inline __isl_give isl_set *copy() const &; inline __isl_give isl_set *copy() && = delete; inline __isl_keep isl_set *get() const; inline __isl_give isl_set *release(); inline bool is_null() const; } The interface and behavior of the new value pointer style classes is inspired by http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3339.pdf, which proposes a std::value_ptr, a smart pointer that applies value semantics to its pointee. We currently only provide a limited set of public constructors and instead require provide a global overloaded type constructor method "isl::obj isl::manage(isl_obj *)", which allows to convert an isl_set* to an isl::set by calling 'S = isl::manage(s)'. This pattern models the make_unique() constructor for unique pointers. The next two functions isl::obj::get() and isl::obj::release() are taken directly from the std::value_ptr proposal: S.get() extracts the raw pointer of the object managed by S. S.release() extracts the raw pointer of the object managed by S and sets the object in S to null. We additionally add std::obj::copy(). S.copy() returns a raw pointer refering to a copy of S, which is a shortcut for "isl::obj(oldobj).release()", a functionality commonly needed when interacting directly with the isl C interface where all methods marked with __isl_take require consumable raw pointers. S.is_null() checks if S manages a pointer or if the managed object is currently null. We add this function to provide a more explicit way to check if the pointer is empty compared to a direct conversion to bool. This commit also introduces a couple of polly-specific extensions that cover features currently not handled by the official isl C++ bindings draft, but which have been provided by IslPtr<T> and are consequently added to avoid code churn. These extensions include: - operator bool() : Conversion from objects to bool - construction from nullptr_t - get_ctx() method - take/keep/give methods, which match the currently used naming convention of IslPtr<T> in Polly. They just forward to (release/get/manage). - raw_ostream printers We expect that these extensions are over time either removed or upstreamed to the official isl bindings. We also export a couple of classes that have not yet been exported in isl (e.g., isl::space) As part of the code review, the following two questions were asked: - Why do we not use a standard smart pointer? std::value_ptr was a proposal that has not been accepted. It is consequently not available in the standard library. Even if it would be available, we want to expand this interface with a complete method interface that is conveniently available from each managed pointer. The most direct way to achieve this is to generate a specialiced value style pointer class for each isl object type and add any additional methods to this class. The relevant changes follow in subsequent commits. - Why do we not use templates or macros to avoid code duplication? It is certainly possible to use templates or macros, but as this code is auto-generated there is no need to make writing this code more efficient. Also, most of these classes will be specialized with individual member functions in subsequent commits, such that there will be little code reuse to exploit. Hence, we decided to do so at the moment. These bindings are not yet officially part of isl, but the draft is already very stable. The smart pointer interface itself did not change since serveral months. Adding this code to Polly is against our normal policy of only importing official isl code. In this case however, we make an exception to showcase a non-trivial use case of these bindings which should increase confidence in these bindings and will help upstreaming them to isl. Tags: #polly Reviewed By: Meinersbur Differential Revision: https://reviews.llvm.org/D30325 llvm-svn: 297452
2017-03-10 19:41:03 +08:00
isl::union_map OldSchedule;
Add -polly-flatten-schedule pass. The -polly-flatten-schedule pass reduces the number of scattering dimensions in its isl_union_map form to make them easier to understand. It is not meant to be used in production, only for debugging and regression tests. To illustrate, how it can make sets simpler, here is a lifetime set used computed by the porposed DeLICM pass without flattening: { Stmt_reduction_for[0, 4] -> [0, 2, o2, o3] : o2 < 0; Stmt_reduction_for[0, 4] -> [0, 1, o2, o3] : o2 >= 5; Stmt_reduction_for[0, 4] -> [0, 1, 4, o3] : o3 > 0; Stmt_reduction_for[0, i1] -> [0, 1, i1, 1] : 0 <= i1 <= 3; Stmt_reduction_for[0, 4] -> [0, 2, 0, o3] : o3 <= 0 } And here the same lifetime for a semantically identical one-dimensional schedule: { Stmt_reduction_for[0, i1] -> [2 + 3i1] : 0 <= i1 <= 4 } Differential Revision: https://reviews.llvm.org/D24310 llvm-svn: 280948
2016-09-08 23:02:36 +08:00
public:
static char ID;
explicit FlattenSchedule() : ScopPass(ID) {}
virtual void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.addRequiredTransitive<ScopInfoRegionPass>();
AU.setPreservesAll();
}
virtual bool runOnScop(Scop &S) override {
// Keep a reference to isl_ctx to ensure that it is not freed before we free
// OldSchedule.
IslCtx = S.getSharedIslCtx();
DEBUG(dbgs() << "Going to flatten old schedule:\n");
OldSchedule = give(S.getSchedule());
DEBUG(printSchedule(dbgs(), OldSchedule, 2));
auto Domains = give(S.getDomains());
[FlattenAlgo] Translate to C++ bindings Translate the full algorithm to use the new isl C++ bindings This is a large piece of code that has been written with the Polly IslPtr<> memory management tool, which only performed memory management, but did not provide a method interface. As such the code was littered with calls to give(), copy(), keep(), and take(). The diff of this change should give a good example how the new method interface simplifies the code by removing the need for switching between managed types and C functions all the time and consequently also the need to use the long C function names. These are a couple of examples comparing the old IslPtr memory management interface with the complete method interface. Check properties ---------------- Before: if (isl_aff_is_zero(Aff.get()) || isl_aff_is_one(Aff.get())) return true; After: if (Aff.is_zero() || Aff.is_one()) return true; Type conversion --------------- Before: isl_union_pw_multi_aff *UPMA = give(isl_union_pw_multi_aff_from_union_map(UMap.copy()); After: isl::union_pw_multi_aff UPMA = UMap; Type construction ----------------- Before: auto Empty = give(isl_union_map_empty(Space.copy()); After: auto Empty = isl::union_map::empty(Space); Operations ---------- Before: Set = give(isl_union_set_intersect(Set.copy(), Set2.copy()); After: Set = Set.intersect(Set2); Tags: #polly Reviewed By: Meinersbur Differential Revision: https://reviews.llvm.org/D30617 llvm-svn: 297463
2017-03-10 22:55:58 +08:00
auto RestrictedOldSchedule = OldSchedule.intersect_domain(Domains);
Add -polly-flatten-schedule pass. The -polly-flatten-schedule pass reduces the number of scattering dimensions in its isl_union_map form to make them easier to understand. It is not meant to be used in production, only for debugging and regression tests. To illustrate, how it can make sets simpler, here is a lifetime set used computed by the porposed DeLICM pass without flattening: { Stmt_reduction_for[0, 4] -> [0, 2, o2, o3] : o2 < 0; Stmt_reduction_for[0, 4] -> [0, 1, o2, o3] : o2 >= 5; Stmt_reduction_for[0, 4] -> [0, 1, 4, o3] : o3 > 0; Stmt_reduction_for[0, i1] -> [0, 1, i1, 1] : 0 <= i1 <= 3; Stmt_reduction_for[0, 4] -> [0, 2, 0, o3] : o3 <= 0 } And here the same lifetime for a semantically identical one-dimensional schedule: { Stmt_reduction_for[0, i1] -> [2 + 3i1] : 0 <= i1 <= 4 } Differential Revision: https://reviews.llvm.org/D24310 llvm-svn: 280948
2016-09-08 23:02:36 +08:00
DEBUG(dbgs() << "Old schedule with domains:\n");
DEBUG(printSchedule(dbgs(), RestrictedOldSchedule, 2));
auto NewSchedule = flattenSchedule(RestrictedOldSchedule);
DEBUG(dbgs() << "Flattened new schedule:\n");
DEBUG(printSchedule(dbgs(), NewSchedule, 2));
[FlattenAlgo] Translate to C++ bindings Translate the full algorithm to use the new isl C++ bindings This is a large piece of code that has been written with the Polly IslPtr<> memory management tool, which only performed memory management, but did not provide a method interface. As such the code was littered with calls to give(), copy(), keep(), and take(). The diff of this change should give a good example how the new method interface simplifies the code by removing the need for switching between managed types and C functions all the time and consequently also the need to use the long C function names. These are a couple of examples comparing the old IslPtr memory management interface with the complete method interface. Check properties ---------------- Before: if (isl_aff_is_zero(Aff.get()) || isl_aff_is_one(Aff.get())) return true; After: if (Aff.is_zero() || Aff.is_one()) return true; Type conversion --------------- Before: isl_union_pw_multi_aff *UPMA = give(isl_union_pw_multi_aff_from_union_map(UMap.copy()); After: isl::union_pw_multi_aff UPMA = UMap; Type construction ----------------- Before: auto Empty = give(isl_union_map_empty(Space.copy()); After: auto Empty = isl::union_map::empty(Space); Operations ---------- Before: Set = give(isl_union_set_intersect(Set.copy(), Set2.copy()); After: Set = Set.intersect(Set2); Tags: #polly Reviewed By: Meinersbur Differential Revision: https://reviews.llvm.org/D30617 llvm-svn: 297463
2017-03-10 22:55:58 +08:00
NewSchedule = NewSchedule.gist_domain(Domains);
Add -polly-flatten-schedule pass. The -polly-flatten-schedule pass reduces the number of scattering dimensions in its isl_union_map form to make them easier to understand. It is not meant to be used in production, only for debugging and regression tests. To illustrate, how it can make sets simpler, here is a lifetime set used computed by the porposed DeLICM pass without flattening: { Stmt_reduction_for[0, 4] -> [0, 2, o2, o3] : o2 < 0; Stmt_reduction_for[0, 4] -> [0, 1, o2, o3] : o2 >= 5; Stmt_reduction_for[0, 4] -> [0, 1, 4, o3] : o3 > 0; Stmt_reduction_for[0, i1] -> [0, 1, i1, 1] : 0 <= i1 <= 3; Stmt_reduction_for[0, 4] -> [0, 2, 0, o3] : o3 <= 0 } And here the same lifetime for a semantically identical one-dimensional schedule: { Stmt_reduction_for[0, i1] -> [2 + 3i1] : 0 <= i1 <= 4 } Differential Revision: https://reviews.llvm.org/D24310 llvm-svn: 280948
2016-09-08 23:02:36 +08:00
DEBUG(dbgs() << "Gisted, flattened new schedule:\n");
DEBUG(printSchedule(dbgs(), NewSchedule, 2));
S.setSchedule(NewSchedule.take());
return false;
}
virtual void printScop(raw_ostream &OS, Scop &S) const override {
OS << "Schedule before flattening {\n";
printSchedule(OS, OldSchedule, 4);
OS << "}\n\n";
OS << "Schedule after flattening {\n";
printSchedule(OS, give(S.getSchedule()), 4);
OS << "}\n";
}
virtual void releaseMemory() override {
OldSchedule = nullptr;
IslCtx.reset();
}
};
char FlattenSchedule::ID;
} // anonymous namespace
Pass *polly::createFlattenSchedulePass() { return new FlattenSchedule(); }
INITIALIZE_PASS_BEGIN(FlattenSchedule, "polly-flatten-schedule",
"Polly - Flatten schedule", false, false)
INITIALIZE_PASS_END(FlattenSchedule, "polly-flatten-schedule",
"Polly - Flatten schedule", false, false)