================ @@ -0,0 +1,259 @@ +//===- LowerWorkshare.cpp - special cases for bufferization -------===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// +// Lower omp workshare construct. +//===----------------------------------------------------------------------===// + +#include "flang/Optimizer/Dialect/FIROps.h" +#include "flang/Optimizer/Dialect/FIRType.h" +#include "flang/Optimizer/OpenMP/Passes.h" +#include "mlir/Dialect/OpenMP/OpenMPDialect.h" +#include "mlir/IR/BuiltinOps.h" +#include "mlir/IR/IRMapping.h" +#include "mlir/IR/OpDefinition.h" +#include "mlir/IR/PatternMatch.h" +#include "mlir/Support/LLVM.h" +#include "mlir/Transforms/GreedyPatternRewriteDriver.h" +#include "llvm/ADT/STLExtras.h" +#include "llvm/ADT/iterator_range.h" + +#include <variant> + +namespace flangomp { +#define GEN_PASS_DEF_LOWERWORKSHARE +#include "flang/Optimizer/OpenMP/Passes.h.inc" +} // namespace flangomp + +#define DEBUG_TYPE "lower-workshare" + +using namespace mlir; + +namespace flangomp { +bool shouldUseWorkshareLowering(Operation *op) { + auto workshare = dyn_cast<omp::WorkshareOp>(op->getParentOp()); + if (!workshare) + return false; + return workshare->getParentOfType<omp::ParallelOp>(); +} +} // namespace flangomp + +namespace { + +struct SingleRegion { + Block::iterator begin, end; +}; + +static bool isSupportedByFirAlloca(Type ty) { + return !isa<fir::ReferenceType>(ty); +} + +static bool isSafeToParallelize(Operation *op) { + if (isa<fir::DeclareOp>(op)) + return true; + + llvm::SmallVector<MemoryEffects::EffectInstance> effects; + MemoryEffectOpInterface interface = dyn_cast<MemoryEffectOpInterface>(op); + if (!interface) { + return false; + } + interface.getEffects(effects); + if (effects.empty()) + return true; + + return false; +} + +/// Lowers workshare to a sequence of single-thread regions and parallel loops +/// +/// For example: +/// +/// omp.workshare { +/// %a = fir.allocmem +/// omp.wsloop {} +/// fir.call Assign %b %a +/// fir.freemem %a +/// } +/// +/// becomes +/// +/// omp.single { +/// %a = fir.allocmem +/// fir.store %a %tmp +/// } +/// %a_reloaded = fir.load %tmp +/// omp.wsloop {} +/// omp.single { +/// fir.call Assign %b %a_reloaded +/// fir.freemem %a_reloaded +/// } +/// +/// Note that we allocate temporary memory for values in omp.single's which need +/// to be accessed in all threads in the closest omp.parallel +/// +/// TODO currently we need to be able to access the encompassing omp.parallel so +/// that we can allocate temporaries accessible by all threads outside of it. +/// In case we do not find it, we fall back to converting the omp.workshare to +/// omp.single. +/// To better handle this we should probably enable yielding values out of an +/// omp.single which will be supported by the omp runtime. +void lowerWorkshare(mlir::omp::WorkshareOp wsOp) { + assert(wsOp.getRegion().getBlocks().size() == 1); + + Location loc = wsOp->getLoc(); + + omp::ParallelOp parallelOp = wsOp->getParentOfType<omp::ParallelOp>(); + if (!parallelOp) { + wsOp.emitWarning("cannot handle workshare, converting to single"); + Operation *terminator = wsOp.getRegion().front().getTerminator(); + wsOp->getBlock()->getOperations().splice( + wsOp->getIterator(), wsOp.getRegion().front().getOperations()); + terminator->erase(); + return; + } + + OpBuilder allocBuilder(parallelOp); + OpBuilder rootBuilder(wsOp); + IRMapping rootMapping; + + omp::SingleOp singleOp = nullptr; + + auto mapReloadedValue = [&](Value v, OpBuilder singleBuilder, + IRMapping singleMapping) { + if (auto reloaded = rootMapping.lookupOrNull(v)) + return; + Type llvmPtrTy = LLVM::LLVMPointerType::get(allocBuilder.getContext()); + Type ty = v.getType(); + Value alloc, reloaded; + if (isSupportedByFirAlloca(ty)) { + alloc = allocBuilder.create<fir::AllocaOp>(loc, ty); + singleBuilder.create<fir::StoreOp>(loc, singleMapping.lookup(v), alloc); ---------------- ivanradanov wrote:
I have opted hoist fir.alloca ops to the parallel region and scattering them using omp.single's copyprivate https://github.com/llvm/llvm-project/pull/101446 _______________________________________________ llvm-branch-commits mailing list llvm-branch-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits
