CreateCanonicalLoop generates a standardized control flow structure for OpenMP canonical for loops. The structure can be consumed by loop-associated directives such as worksharing-loop, distribute, simd etc. as well as loop transformations such as tile and unroll.
This is a first design without considering all complexities yet. The control-flow emits more basic block than strictly necessary, but these will be optimized by CFGSimplify anyway, provide a nice separation of concerns and might later be useful with more complex scenarios. I successfully implemented a basic tile construct using this API, which is not part of this patch.
The fundamental building block is the CreateCanonicalLoop that only takes the loop trip count and operates on the logical iteration spaces only. An overloaded CreateCanonicalLoop for using LB, UB, Increment is provided as well, but at least for C++, Clang will need to implement a loop counter to logical induction variable mapping anyway, since iterator overload resolution cannot be done in LLVMFrontend.
As there currently is no user for CreateCanonicalLoop, it is only called from unittests. Similarly, CanonicalLoopInfo::eraseFromParent() is used in my file implementation and might be generally useful for implementing loop-associated constructs, but is not used in this patch itself.
The following non-exhaustive list describes not yet covered items:
* collapse clause (including non-rectangular and non-perfectly nested); idea is to provide a OpenMPIRBuilder::collapseLoopNest method consuming multiple nested loops and returning a new CanonicalLoopInfo that can be used for loop-associated directives.
* simarly: ordered clause for DOACROSS loops
* branch weights
* Cancellation point (?)
* AllocaIP
* break statement (if needed at all)
* Exceptions (if not completely handled in the front-end)
* Using it in Clang; this requires implementing at least one loop-associated construct.
* ...
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D90830
We need to keep track of the alloca insertion point (which we already
communicate via the callback to the user) as we place allocas as well.
Reviewed By: fghanim, SouraVX
Differential Revision: https://reviews.llvm.org/D82470
It was unclear what `isa` was supposed to mean so we did not provide any
traits for this context selector. With this patch we will allow *any*
string or identifier. We use the target attribute and target info to
determine if the trait matches. In other words, we will check if the
provided value is a target feature that is available (at the call site).
Fixes PR46338
Reviewed By: ABataev
Differential Revision: https://reviews.llvm.org/D83281
Summary:
D82193 exposed a problem with global type definitions in
`OMPConstants.h`. This causes a race when running in thinLTO mode.
Types now live inside of OpenMPIRBuilder to prevent this from happening.
Reviewers: jdoerfert
Subscribers: yaxunl, hiraditya, guansong, dexonsmith, aaron.ballman, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D83176
Add support for Master and Critical directive in the OMPIRBuilder. Both make use of a new common interface for emitting inlined OMP regions called `emitInlinedRegion` which was added in this patch as well.
Also this patch modifies clang to use the new directives when `-fopenmp-enable-irbuilder` commandline option is passed.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D72304
This patch implements an almost complete handling of OpenMP
contexts/traits such that we can reuse most of the logic in Flang
through the OMPContext.{h,cpp} in llvm/Frontend/OpenMP.
All but construct SIMD specifiers, e.g., inbranch, and the device ISA
selector are define in `llvm/lib/Frontend/OpenMP/OMPKinds.def`. From
these definitions we generate the enum classes `TraitSet`,
`TraitSelector`, and `TraitProperty` as well as conversion and helper
functions in `llvm/lib/Frontend/OpenMP/OMPContext.{h,cpp}`.
The above enum classes are used in the parser, sema, and the AST
attribute. The latter is not a collection of multiple primitive variant
arguments that contain encodings via numbers and strings but instead a
tree that mirrors the `match` clause (see `struct OpenMPTraitInfo`).
The changes to the parser make it more forgiving when wrong syntax is
read and they also resulted in more specialized diagnostics. The tests
are updated and the core issues are detected as before. Here and
elsewhere this patch tries to be generic, thus we do not distinguish
what selector set, selector, or property is parsed except if they do
behave exceptionally, as for example `user={condition(EXPR)}` does.
The sema logic changed in two ways: First, the OMPDeclareVariantAttr
representation changed, as mentioned above, and the sema was adjusted to
work with the new `OpenMPTraitInfo`. Second, the matching and scoring
logic moved into `OMPContext.{h,cpp}`. It is implemented on a flat
representation of the `match` clause that is not tied to clang.
`OpenMPTraitInfo` provides a method to generate this flat structure (see
`struct VariantMatchInfo`) by computing integer score values and boolean
user conditions from the `clang::Expr` we keep for them.
The OpenMP context is now an explicit object (see `struct OMPContext`).
This is in anticipation of construct traits that need to be tracked. The
OpenMP context, as well as the `VariantMatchInfo`, are basically made up
of a set of active or respectively required traits, e.g., 'host', and an
ordered container of constructs which allows duplication. Matching and
scoring is kept as generic as possible to allow easy extension in the
future.
---
Test changes:
The messages checked in `OpenMP/declare_variant_messages.{c,cpp}` have
been auto generated to match the new warnings and notes of the parser.
The "subset" checks were reversed causing the wrong version to be
picked. The tests have been adjusted to correct this.
We do not print scores if the user did not provide one.
We print spaces to make lists in the `match` clause more legible.
Reviewers: kiranchandramohan, ABataev, RaviNarayanaswamy, gtbercea, grokos, sdmitriev, JonChesterfield, hfinkel, fghanim
Subscribers: merge_guards_bot, rampitec, mgorny, hiraditya, aheejin, fedor.sergeev, simoncook, bollu, guansong, dexonsmith, jfb, s.egerton, llvm-commits, cfe-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D71830
Finalization can introduce new blocks we need to outline as well so it
makes sense to identify the blocks that need to be outlined after
finalization happened. There was also a minor unit test adjustment to
account for the fact that we have a single outlined exit block now.
Reapply 8a56d64d7620b3764f10f03f3a1e307fcdd72c2f with minor fixes.
The problem was that cancellation can cause new edges to the parallel
region exit block which is not outlined. The CodeExtractor will encode
the information which "exit" was taken as a return value. The fix is to
ensure we do not return any value from the outlined function, to prevent
control to value conversion we ensure a single exit block for the
outlined region.
This reverts commit 3aac953afa34885a72df96f2b703b65f85cbb149.
In order to fix PR44560 and to prepare for loop transformations we now
finalize a function late, which will also do the outlining late. The
logic is as before but the actual outlining step happens now after the
function was fully constructed. Once we have loop transformations we
can apply them in the finalize step before the outlining.
Reviewed By: JonChesterfield
Differential Revision: https://reviews.llvm.org/D74372
This breaks under asan, see http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux-fast/builds/38597/steps/check-clang%20asan/logs/stdio
This reverts commit bb5045429545f47a76980864322a637c31594c7f.
Revert "[FIX] Ordering problem accidentally introduced with D72304"
This reverts commit 08c0a06d8f375e48d4acebac886bfdf19a2276ed.
Revert "[OpenMP][OMPIRBuilder] Add Directives (master and critical) to OMPBuilder."
This reverts commit e8a436c5ea26f69378e4c1cf3ddb5b647b201e0f.
Add support for Master and Critical directive in the OMPIRBuilder. Both make use of a new common interface for emitting inlined OMP regions called `emitInlinedRegion` which was added in this patch as well.
Also this patch modifies clang to use the new directives when `-fopenmp-enable-irbuilder` commandline option is passed.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D72304
Add support for Master and Critical directive in the OMPIRBuilder. Both make use of a new common interface for emitting inlined OMP regions called `emitInlinedRegion` which was added in this patch as well.
Also this patch modifies clang to use the new directives when `-fopenmp-enable-irbuilder` commandline option is passed.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D72304
This is the first of multiple parts to make OpenMP context/trait
handling reusable and generic. This patch was originally part of D71830
but with the unit tests it can be tested independently.
This patch implements an almost complete handling of OpenMP
contexts/traits such that we can reuse most of the logic in Flang
through the OMPContext.{h,cpp} in llvm/Frontend/OpenMP.
All but construct SIMD specifiers, e.g., inbranch, and the device ISA
selector are define in llvm/lib/Frontend/OpenMP/OMPKinds.def. From
these definitions we generate the enum classes TraitSet,
TraitSelector, and TraitProperty as well as conversion and helper
functions in llvm/lib/Frontend/OpenMP/OMPContext.{h,cpp}.
The OpenMP context is now an explicit object (see `struct OMPContext`).
This is in anticipation of construct traits that need to be tracked. The
OpenMP context, as well as the VariantMatchInfo, are basically made up
of a set of active or respectively required traits, e.g., 'host', and an
ordered container of constructs which allows duplication. Matching and
scoring is kept as generic as possible to allow easy extension in the
future.
Reviewed By: JonChesterfield
Differential Revision: https://reviews.llvm.org/D71847
This allows to use the OpenMPIRBuilder for parallel regions. Code was
extracted from D61953 and adapted to work with the new version (D70109).
All but one feature should be supported. An update of this patch will
provide test coverage and privatization other than shared.
Reviewed By: fghanim
Differential Revision: https://reviews.llvm.org/D70290
An `omp cancel parallel` needs to be emitted by the OpenMPIRBuilder if
the `parallel` was emitted by the OpenMPIRBuilder. This patch makes
this possible. The cancel logic is shared with the cancel barriers.
Testing is done via unit tests and the clang cancel_codegen.cpp file
once D70290 lands.
Reviewed By: JonChesterfield
Differential Revision: https://reviews.llvm.org/D71948
This removes the OpenMPProcBindClauseKind enum in favor of
llvm::omp::ProcBindKind which lives in OpenMPConstants.h and was
introduced in D70109.
No change in behavior is expected.
Reviewed By: JonChesterfield
Differential Revision: https://reviews.llvm.org/D70289
This patch combines the `emitParallel` logic prototyped in D61953 with
the OpenMPIRBuilder (D69785) and introduces `CreateParallel`.
Reviewed By: fghanim
Differential Revision: https://reviews.llvm.org/D70109
As a permanent and generic solution to the problem of variable
finalization (destructors, lastprivate, ...), this patch introduces the
finalization stack. The objects on the stack describe (1) the
(structured) regions the OpenMP-IR-Builder is currently constructing,
(2) if these are cancellable, and (3) the callback that will perform the
finalization (=cleanup) when necessary.
As the finalization can be necessary multiple times, at different source
locations, the callback takes the position at which code is currently
generated. This position will also encode the destination of the "region
exit" block *iff* the finalization call was issues for a region
generated by the OpenMPIRBuilder. For regions generated through the old
Clang OpenMP code geneneration, the "region exit" is determined by Clang
inside the finalization call instead (see getOMPCancelDestination).
As a first user, the parallel + cancel barrier interaction is changed.
In contrast to the temporary solution before, the barrier generation in
Clang does not need to be aware of the "CancelDestination" block.
Instead, the finalization callback is and, as described above, later
even that one does not need to be.
D70109 will be updated to use this scheme.
Reviewed By: ABataev
Differential Revision: https://reviews.llvm.org/D70258
This is the initial patch for the OpenMP-IR-Builder, as discussed on the
mailing list ([1] and later) and at the US Dev Meeting'19.
The design is similar to D61953 but:
- in a non-WIP status, with proper documentation and working.
- using a OpenMPKinds.def file to manage lists of directives, runtime
functions, types, ..., similar to the current Clang implementation.
- restricted to handle only (simple) barriers, to implement most
`#pragma omp barrier` directives and most implicit barriers.
- properly hooked into Clang to be used if possible (D69922).
- compatible with the remaining code generation.
Parts have been extracted into D69853.
The plan is to have multiple people working on moving logic from Clang
here once the initial scaffolding (=this patch) landed.
[1] http://lists.flang-compiler.org/pipermail/flang-dev_lists.flang-compiler.org/2019-May/000197.html
Reviewers: kiranchandramohan, ABataev, RaviNarayanaswamy, gtbercea, grokos, sdmitriev, JonChesterfield, hfinkel, fghanim
Subscribers: mgorny, hiraditya, bollu, guansong, jfb, cfe-commits, llvm-commits, penzn, ppenzin
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D69785
