[MLIR][OpenMP] Extend omp.private materialization support: dealloc
#90841
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Extends current support for delayed privatization during translation to LLVM IR. This adds support for materlizaing the `dealloc` region in `omp.private` ops when this region contains clean-up/deallocation logic that needs to be executed at the end of the parallel region.
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mlir:llvm
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mlir:openmp
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clang:openmp
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@llvm/pr-subscribers-mlir-llvm @llvm/pr-subscribers-flang-openmp Author: Kareem Ergawy (ergawy) ChangesExtends current support for delayed privatization during translation to LLVM IR. This adds support for materlizaing the Full diff: https://github.com/llvm/llvm-project/pull/90841.diff 3 Files Affected:
diff --git a/llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp b/llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp
index 4d2d352f7520b2..9f0c07ef0da910 100644
--- a/llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp
+++ b/llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp
@@ -1500,19 +1500,6 @@ IRBuilder<>::InsertPoint OpenMPIRBuilder::createParallel(
};
}
- // Adjust the finalization stack, verify the adjustment, and call the
- // finalize function a last time to finalize values between the pre-fini
- // block and the exit block if we left the parallel "the normal way".
- auto FiniInfo = FinalizationStack.pop_back_val();
- (void)FiniInfo;
- assert(FiniInfo.DK == OMPD_parallel &&
- "Unexpected finalization stack state!");
-
- Instruction *PRegPreFiniTI = PRegPreFiniBB->getTerminator();
-
- InsertPointTy PreFiniIP(PRegPreFiniBB, PRegPreFiniTI->getIterator());
- FiniCB(PreFiniIP);
-
OI.OuterAllocaBB = OuterAllocaBlock;
OI.EntryBB = PRegEntryBB;
OI.ExitBB = PRegExitBB;
@@ -1637,6 +1624,19 @@ IRBuilder<>::InsertPoint OpenMPIRBuilder::createParallel(
dbgs() << " PBR: " << BB->getName() << "\n";
});
+ // Adjust the finalization stack, verify the adjustment, and call the
+ // finalize function a last time to finalize values between the pre-fini
+ // block and the exit block if we left the parallel "the normal way".
+ auto FiniInfo = FinalizationStack.pop_back_val();
+ (void)FiniInfo;
+ assert(FiniInfo.DK == OMPD_parallel &&
+ "Unexpected finalization stack state!");
+
+ Instruction *PRegPreFiniTI = PRegPreFiniBB->getTerminator();
+
+ InsertPointTy PreFiniIP(PRegPreFiniBB, PRegPreFiniTI->getIterator());
+ FiniCB(PreFiniIP);
+
// Register the outlined info.
addOutlineInfo(std::move(OI));
diff --git a/mlir/lib/Target/LLVMIR/Dialect/OpenMP/OpenMPToLLVMIRTranslation.cpp b/mlir/lib/Target/LLVMIR/Dialect/OpenMP/OpenMPToLLVMIRTranslation.cpp
index 9f87f89d8c636b..6cfe5c038afa42 100644
--- a/mlir/lib/Target/LLVMIR/Dialect/OpenMP/OpenMPToLLVMIRTranslation.cpp
+++ b/mlir/lib/Target/LLVMIR/Dialect/OpenMP/OpenMPToLLVMIRTranslation.cpp
@@ -33,6 +33,7 @@
#include "llvm/Transforms/Utils/ModuleUtils.h"
#include <any>
+#include <iterator>
#include <optional>
#include <utility>
@@ -878,36 +879,40 @@ static void collectReductionInfo(
}
/// handling of DeclareReductionOp's cleanup region
-static LogicalResult inlineReductionCleanup(
- llvm::SmallVectorImpl<omp::DeclareReductionOp> &reductionDecls,
- llvm::ArrayRef<llvm::Value *> privateReductionVariables,
- LLVM::ModuleTranslation &moduleTranslation, llvm::IRBuilderBase &builder) {
- for (auto [i, reductionDecl] : llvm::enumerate(reductionDecls)) {
- Region &cleanupRegion = reductionDecl.getCleanupRegion();
- if (cleanupRegion.empty())
+static LogicalResult
+inlineOmpRegionCleanup(llvm::SmallVectorImpl<Region *> &cleanupRegions,
+ llvm::ArrayRef<llvm::Value *> privateVariables,
+ LLVM::ModuleTranslation &moduleTranslation,
+ llvm::IRBuilderBase &builder, StringRef regionName,
+ bool shouldLoadCleanupRegionArg = true) {
+ for (auto [i, cleanupRegion] : llvm::enumerate(cleanupRegions)) {
+ if (cleanupRegion->empty())
continue;
// map the argument to the cleanup region
- Block &entry = cleanupRegion.front();
+ Block &entry = cleanupRegion->front();
llvm::Instruction *potentialTerminator =
builder.GetInsertBlock()->empty() ? nullptr
: &builder.GetInsertBlock()->back();
if (potentialTerminator && potentialTerminator->isTerminator())
builder.SetInsertPoint(potentialTerminator);
- llvm::Value *reductionVar = builder.CreateLoad(
- moduleTranslation.convertType(entry.getArgument(0).getType()),
- privateReductionVariables[i]);
+ llvm::Value *prviateVarValue =
+ shouldLoadCleanupRegionArg
+ ? builder.CreateLoad(
+ moduleTranslation.convertType(entry.getArgument(0).getType()),
+ privateVariables[i])
+ : privateVariables[i];
- moduleTranslation.mapValue(entry.getArgument(0), reductionVar);
+ moduleTranslation.mapValue(entry.getArgument(0), prviateVarValue);
- if (failed(inlineConvertOmpRegions(cleanupRegion, "omp.reduction.cleanup",
- builder, moduleTranslation)))
+ if (failed(inlineConvertOmpRegions(*cleanupRegion, regionName, builder,
+ moduleTranslation)))
return failure();
// clear block argument mapping in case it needs to be re-created with a
// different source for another use of the same reduction decl
- moduleTranslation.forgetMapping(cleanupRegion);
+ moduleTranslation.forgetMapping(*cleanupRegion);
}
return success();
}
@@ -1110,8 +1115,14 @@ convertOmpWsloop(Operation &opInst, llvm::IRBuilderBase &builder,
builder.restoreIP(nextInsertionPoint);
// after the workshare loop, deallocate private reduction variables
- return inlineReductionCleanup(reductionDecls, privateReductionVariables,
- moduleTranslation, builder);
+ SmallVector<Region *> reductionRegions;
+ llvm::transform(reductionDecls, std::back_inserter(reductionRegions),
+ [](omp::DeclareReductionOp reductionDecl) {
+ return &reductionDecl.getCleanupRegion();
+ });
+ return inlineOmpRegionCleanup(reductionRegions, privateReductionVariables,
+ moduleTranslation, builder,
+ "omp.reduction.cleanup");
}
/// A RAII class that on construction replaces the region arguments of the
@@ -1267,6 +1278,10 @@ convertOmpParallel(omp::ParallelOp opInst, llvm::IRBuilderBase &builder,
}
};
+ SmallVector<omp::PrivateClauseOp> privatizerClones;
+ SmallVector<llvm::Value *> privateVariables;
+
+
// TODO: Perform appropriate actions according to the data-sharing
// attribute (shared, private, firstprivate, ...) of variables.
// Currently shared and private are supported.
@@ -1356,12 +1371,17 @@ convertOmpParallel(omp::ParallelOp opInst, llvm::IRBuilderBase &builder,
opInst.emitError("failed to inline `alloc` region of an `omp.private` "
"op in the parallel region");
bodyGenStatus = failure();
+ privatizerClone.erase();
} else {
assert(yieldedValues.size() == 1);
replacementValue = yieldedValues.front();
+
+ // Keep the LLVM replacement value and the op clone in case we need to
+ // emit cleanup (i.e. deallocation) logic.
+ privateVariables.push_back(replacementValue);
+ privatizerClones.push_back(privatizerClone);
}
- privatizerClone.erase();
builder.restoreIP(oldIP);
}
@@ -1376,8 +1396,25 @@ convertOmpParallel(omp::ParallelOp opInst, llvm::IRBuilderBase &builder,
// if the reduction has a cleanup region, inline it here to finalize the
// reduction variables
- if (failed(inlineReductionCleanup(reductionDecls, privateReductionVariables,
- moduleTranslation, builder)))
+ SmallVector<Region *> reductionCleanupRegions;
+ llvm::transform(reductionDecls, std::back_inserter(reductionCleanupRegions),
+ [](omp::DeclareReductionOp reductionDecl) {
+ return &reductionDecl.getCleanupRegion();
+ });
+ if (failed(inlineOmpRegionCleanup(
+ reductionCleanupRegions, privateReductionVariables, moduleTranslation,
+ builder, "omp.reduction.cleanup")))
+ bodyGenStatus = failure();
+
+ SmallVector<Region *> privateCleanupRegions;
+ llvm::transform(privatizerClones, std::back_inserter(privateCleanupRegions),
+ [](omp::PrivateClauseOp privatizer) {
+ return &privatizer.getDeallocRegion();
+ });
+
+ if (failed(inlineOmpRegionCleanup(
+ privateCleanupRegions, privateVariables, moduleTranslation, builder,
+ "omp.private.dealloc", /*shouldLoadCleanupRegionArg=*/false)))
bodyGenStatus = failure();
builder.restoreIP(oldIP);
@@ -1403,6 +1440,9 @@ convertOmpParallel(omp::ParallelOp opInst, llvm::IRBuilderBase &builder,
ompBuilder->createParallel(ompLoc, allocaIP, bodyGenCB, privCB, finiCB,
ifCond, numThreads, pbKind, isCancellable));
+ for (mlir::omp::PrivateClauseOp privatizerClone : privatizerClones)
+ privatizerClone.erase();
+
return bodyGenStatus;
}
diff --git a/mlir/test/Target/LLVMIR/openmp-omp.private-dealloc.mlir b/mlir/test/Target/LLVMIR/openmp-omp.private-dealloc.mlir
new file mode 100644
index 00000000000000..835caccb262c46
--- /dev/null
+++ b/mlir/test/Target/LLVMIR/openmp-omp.private-dealloc.mlir
@@ -0,0 +1,53 @@
+// RUN: mlir-translate -mlir-to-llvmir -split-input-file %s | FileCheck %s
+
+llvm.func @free(!llvm.ptr)
+
+llvm.func @parallel_op_dealloc(%arg0: !llvm.ptr) {
+ omp.parallel private(@x.privatizer %arg0 -> %arg2 : !llvm.ptr) {
+ %0 = llvm.load %arg2 : !llvm.ptr -> f32
+ omp.terminator
+ }
+ llvm.return
+}
+
+omp.private {type = firstprivate} @x.privatizer : !llvm.ptr alloc {
+^bb0(%arg0: !llvm.ptr):
+ %c1 = llvm.mlir.constant(1 : i32) : i32
+ %0 = llvm.alloca %c1 x f32 : (i32) -> !llvm.ptr
+ omp.yield(%0 : !llvm.ptr)
+} copy {
+^bb0(%arg0: !llvm.ptr, %arg1: !llvm.ptr):
+ %0 = llvm.load %arg0 : !llvm.ptr -> f32
+ llvm.store %0, %arg1 : f32, !llvm.ptr
+ omp.yield(%arg1 : !llvm.ptr)
+} dealloc {
+^bb0(%arg0: !llvm.ptr):
+ %0 = llvm.ptrtoint %arg0 : !llvm.ptr to i64
+ %c0 = llvm.mlir.constant(0 : i64) : i64
+ %1 = llvm.icmp "ne" %0, %c0 : i64
+ llvm.cond_br %1, ^bb1, ^bb2
+
+^bb1:
+ llvm.call @free(%arg0) : (!llvm.ptr) -> ()
+ llvm.br ^bb2
+
+^bb2:
+ omp.yield
+}
+
+// CHECK-LABEL: define internal void @parallel_op_dealloc..omp_par
+// CHECK: %[[LOCAL_ALLOC:.*]] = alloca float, align 4
+
+// CHECK: omp.par.pre_finalize:
+// CHECK: br label %[[DEALLOC_REG_START:.*]]
+
+// CHECK: [[DEALLOC_REG_START]]:
+// CHECK: %[[LOCAL_ALLOC_CONV:.*]] = ptrtoint ptr %[[LOCAL_ALLOC]] to i64
+// CHECK: %[[COND:.*]] = icmp ne i64 %[[LOCAL_ALLOC_CONV]], 0
+// CHECK: br i1 %[[COND]], label %[[DEALLOC_REG_BB1:.*]], label %[[DEALLOC_REG_BB2:.*]]
+
+// CHECK: [[DEALLOC_REG_BB2]]:
+
+// CHECK: [[DEALLOC_REG_BB1]]:
+// CHECK-NEXT: call void @free(ptr %[[LOCAL_ALLOC]])
+// CHECK-NEXT: br label %[[DEALLOC_REG_BB2]]
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✅ With the latest revision this PR passed the C/C++ code formatter. |
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Extends current support for delayed privatization during translation to LLVM IR. This adds support for materlizaing the
deallocregion inomp.privateops when this region contains clean-up/deallocation logic that needs to be executed at the end of the parallel region.This changes the
OMPIRBuilderslightly to execute the finalization callback after the privatization callback. This allows us to collect information about privatized variables on the MLIR and LLVM sides so that we can properly emit deallocation logic.