[MLIR][OpenMP] Add canonical loop LLVM-IR lowering #147069
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@llvm/pr-subscribers-flang-openmp @llvm/pr-subscribers-mlir Author: Michael Kruse (Meinersbur) ChangesSupport for translating the operations introduced in #144785 to LLVM-IR. In order to keep the lowering simple, Eventually, all transformations on a loop must be applied directly after emitting Patch is 21.16 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/147069.diff 6 Files Affected:
diff --git a/mlir/include/mlir/Target/LLVMIR/ModuleTranslation.h b/mlir/include/mlir/Target/LLVMIR/ModuleTranslation.h
index 79e8bb6add0da..5d52cf3f04b6a 100644
--- a/mlir/include/mlir/Target/LLVMIR/ModuleTranslation.h
+++ b/mlir/include/mlir/Target/LLVMIR/ModuleTranslation.h
@@ -15,6 +15,7 @@
#define MLIR_TARGET_LLVMIR_MODULETRANSLATION_H
#include "mlir/Dialect/LLVMIR/LLVMInterfaces.h"
+#include "mlir/Dialect/OpenMP/OpenMPDialect.h"
#include "mlir/IR/Operation.h"
#include "mlir/IR/SymbolTable.h"
#include "mlir/IR/Value.h"
@@ -24,6 +25,7 @@
#include "mlir/Target/LLVMIR/TypeToLLVM.h"
#include "llvm/ADT/SetVector.h"
+#include "llvm/Frontend/OpenMP/OMPIRBuilder.h"
#include "llvm/IR/FPEnv.h"
namespace llvm {
@@ -108,6 +110,41 @@ class ModuleTranslation {
return blockMapping.lookup(block);
}
+ /// Find the LLVM-IR loop that represents an MLIR loop.
+ llvm::CanonicalLoopInfo *lookupOMPLoop(omp::NewCliOp mlir) const {
+ llvm::CanonicalLoopInfo *result = loopMapping.lookup(mlir);
+ assert(result && "attempt to get non-existing loop");
+ return result;
+ }
+
+ /// Find the LLVM-IR loop that represents an MLIR loop.
+ llvm::CanonicalLoopInfo *lookupOMPLoop(Value mlir) const {
+ return lookupOMPLoop(mlir.getDefiningOp<omp::NewCliOp>());
+ }
+
+ /// Mark an OpenMP loop as having been consumed.
+ void invalidateOmpLoop(omp::NewCliOp mlir) { loopMapping.erase(mlir); }
+
+ /// Mark an OpenMP loop as having been consumed.
+ void invalidateOmpLoop(Value mlir) {
+ invalidateOmpLoop(mlir.getDefiningOp<omp::NewCliOp>());
+ }
+
+ /// Map an MLIR OpenMP dialect CanonicalLoopInfo to its lowered LLVM-IR
+ /// OpenMPIRBuilder CanonicalLoopInfo
+ void mapOmpLoop(omp::NewCliOp mlir, llvm::CanonicalLoopInfo *llvm) {
+ assert(llvm && "argument must be non-null");
+ llvm::CanonicalLoopInfo *&cur = loopMapping[mlir];
+ assert(cur == nullptr && "attempting to map a loop that is already mapped");
+ cur = llvm;
+ }
+
+ /// Map an MLIR OpenMP dialect CanonicalLoopInfo to its lowered LLVM-IR
+ /// OpenMPIRBuilder CanonicalLoopInfo
+ void mapOmpLoop(Value mlir, llvm::CanonicalLoopInfo *llvm) {
+ mapOmpLoop(mlir.getDefiningOp<omp::NewCliOp>(), llvm);
+ }
+
/// Stores the mapping between an MLIR operation with successors and a
/// corresponding LLVM IR instruction.
void mapBranch(Operation *mlir, llvm::Instruction *llvm) {
@@ -381,6 +418,12 @@ class ModuleTranslation {
DenseMap<Value, llvm::Value *> valueMapping;
DenseMap<Block *, llvm::BasicBlock *> blockMapping;
+ /// List of not yet consumed MLIR loop handles (represented by an omp.new_cli
+ /// operation which creates a value of type CanonicalLoopInfoType) and their
+ /// LLVM-IR representation as CanonicalLoopInfo which is managed by the
+ /// OpenMPIRBuilder.
+ DenseMap<omp::NewCliOp, llvm::CanonicalLoopInfo *> loopMapping;
+
/// A mapping between MLIR LLVM dialect terminators and LLVM IR terminators
/// they are converted to. This allows for connecting PHI nodes to the source
/// values after all operations are converted.
diff --git a/mlir/lib/Conversion/OpenMPToLLVM/OpenMPToLLVM.cpp b/mlir/lib/Conversion/OpenMPToLLVM/OpenMPToLLVM.cpp
index 77a2708653576..7ac9687c4eeda 100644
--- a/mlir/lib/Conversion/OpenMPToLLVM/OpenMPToLLVM.cpp
+++ b/mlir/lib/Conversion/OpenMPToLLVM/OpenMPToLLVM.cpp
@@ -41,6 +41,16 @@ template <typename T>
struct OpenMPOpConversion : public ConvertOpToLLVMPattern<T> {
using ConvertOpToLLVMPattern<T>::ConvertOpToLLVMPattern;
+ OpenMPOpConversion(LLVMTypeConverter &typeConverter,
+ PatternBenefit benefit = 1)
+ : ConvertOpToLLVMPattern<T>(typeConverter, benefit) {
+ // Operations using CanonicalLoopInfoType are lowered only by
+ // mlir::translateModuleToLLVMIR() using the OpenMPIRBuilder. Until then,
+ // the type and operations using it must be preserved.
+ typeConverter.addConversion(
+ [&](::mlir::omp::CanonicalLoopInfoType type) { return type; });
+ }
+
LogicalResult
matchAndRewrite(T op, typename T::Adaptor adaptor,
ConversionPatternRewriter &rewriter) const override {
diff --git a/mlir/lib/Target/LLVMIR/Dialect/OpenMP/OpenMPToLLVMIRTranslation.cpp b/mlir/lib/Target/LLVMIR/Dialect/OpenMP/OpenMPToLLVMIRTranslation.cpp
index 7a517fb86d1ff..8b9bf7cb2a393 100644
--- a/mlir/lib/Target/LLVMIR/Dialect/OpenMP/OpenMPToLLVMIRTranslation.cpp
+++ b/mlir/lib/Target/LLVMIR/Dialect/OpenMP/OpenMPToLLVMIRTranslation.cpp
@@ -3096,6 +3096,67 @@ convertOmpLoopNest(Operation &opInst, llvm::IRBuilderBase &builder,
return success();
}
+/// Convert an omp.canonical_loop to LLVM-IR
+static LogicalResult
+convertOmpCanonicalLoopOp(omp::CanonicalLoopOp op, llvm::IRBuilderBase &builder,
+ LLVM::ModuleTranslation &moduleTranslation) {
+ llvm::OpenMPIRBuilder *ompBuilder = moduleTranslation.getOpenMPBuilder();
+
+ llvm::OpenMPIRBuilder::LocationDescription loopLoc(builder);
+ Value loopIV = op.getInductionVar();
+ Value loopTC = op.getTripCount();
+
+ llvm::Value *llvmTC = moduleTranslation.lookupValue(loopTC);
+
+ llvm::Expected<llvm::CanonicalLoopInfo *> llvmOrError =
+ ompBuilder->createCanonicalLoop(
+ loopLoc,
+ [&](llvm::OpenMPIRBuilder::InsertPointTy ip, llvm::Value *llvmIV) {
+ // Register the mapping of MLIR induction variable to LLVM-IR
+ // induction variable
+ moduleTranslation.mapValue(loopIV, llvmIV);
+
+ builder.restoreIP(ip);
+ llvm::Expected<llvm::BasicBlock *> bodyGenStatus =
+ convertOmpOpRegions(op.getRegion(), "omp.loop.region", builder,
+ moduleTranslation);
+
+ return bodyGenStatus.takeError();
+ },
+ llvmTC, "omp.loop");
+ if (!llvmOrError)
+ return op.emitError(llvm::toString(llvmOrError.takeError()));
+
+ llvm::CanonicalLoopInfo *llvmCLI = *llvmOrError;
+ llvm::IRBuilderBase::InsertPoint afterIP = llvmCLI->getAfterIP();
+ builder.restoreIP(afterIP);
+
+ // Register the mapping of MLIR loop to LLVM-IR OpenMPIRBuilder loop
+ if (Value cli = op.getCli())
+ moduleTranslation.mapOmpLoop(cli, llvmCLI);
+
+ return success();
+}
+
+/// Apply a `#pragma omp unroll` / "!$omp unroll" transformation using the
+/// OpenMPIRBuilder.
+static LogicalResult
+applyUnrollHeuristic(omp::UnrollHeuristicOp op, llvm::IRBuilderBase &builder,
+ LLVM::ModuleTranslation &moduleTranslation) {
+ llvm::OpenMPIRBuilder *ompBuilder = moduleTranslation.getOpenMPBuilder();
+
+ Value applyee = op.getApplyee();
+ assert(applyee && "Loop to apply unrolling on required");
+
+ llvm::CanonicalLoopInfo *consBuilderCLI =
+ moduleTranslation.lookupOMPLoop(applyee);
+ llvm::OpenMPIRBuilder::LocationDescription loc(builder);
+ ompBuilder->unrollLoopHeuristic(loc.DL, consBuilderCLI);
+
+ moduleTranslation.invalidateOmpLoop(applyee);
+ return success();
+}
+
/// Convert an Atomic Ordering attribute to llvm::AtomicOrdering.
static llvm::AtomicOrdering
convertAtomicOrdering(std::optional<omp::ClauseMemoryOrderKind> ao) {
@@ -5988,6 +6049,23 @@ convertHostOrTargetOperation(Operation *op, llvm::IRBuilderBase &builder,
// etc. and then discarded
return success();
})
+ .Case([&](omp::NewCliOp op) {
+ // Meta-operation: Doesn't do anything by itself, but used to
+ // identify a loop.
+ return success();
+ })
+ .Case([&](omp::CanonicalLoopOp op) {
+ return convertOmpCanonicalLoopOp(op, builder, moduleTranslation);
+ })
+ .Case([&](omp::UnrollHeuristicOp op) {
+ // FIXME: Handling omp.unroll_heuristic as an executable requires
+ // that the generator (e.g. omp.canonical_loop) has been seen first.
+ // For construct that require all codegen to occur inside a callback
+ // (e.g. OpenMPIRBilder::createParallel), all codegen of that
+ // contained region including their transformations must occur at
+ // the omp.canonical_loop.
+ return applyUnrollHeuristic(op, builder, moduleTranslation);
+ })
.Default([&](Operation *inst) {
return inst->emitError()
<< "not yet implemented: " << inst->getName();
diff --git a/mlir/test/Target/LLVMIR/openmp-cli-canonical_loop.mlir b/mlir/test/Target/LLVMIR/openmp-cli-canonical_loop.mlir
new file mode 100644
index 0000000000000..9abef003d6183
--- /dev/null
+++ b/mlir/test/Target/LLVMIR/openmp-cli-canonical_loop.mlir
@@ -0,0 +1,175 @@
+// Test lowering of standalone omp.canonical_loop
+// RUN: mlir-translate -mlir-to-llvmir %s | FileCheck %s
+
+// CHECK-LABEL: define void @anon_loop(
+// CHECK-SAME: ptr %[[ptr:.+]],
+// CHECK-SAME: i32 %[[tc:.+]]) {
+// CHECK-NEXT: br label %omp_omp.loop.preheader
+// CHECK-EMPTY:
+// CHECK-NEXT: omp_omp.loop.preheader:
+// CHECK-NEXT: br label %omp_omp.loop.header
+// CHECK-EMPTY:
+// CHECK-NEXT: omp_omp.loop.header:
+// CHECK-NEXT: %omp_omp.loop.iv = phi i32 [ 0, %omp_omp.loop.preheader ], [ %omp_omp.loop.next, %omp_omp.loop.inc ]
+// CHECK-NEXT: br label %omp_omp.loop.cond
+// CHECK-EMPTY:
+// CHECK-NEXT: omp_omp.loop.cond:
+// CHECK-NEXT: %omp_omp.loop.cmp = icmp ult i32 %omp_omp.loop.iv, %[[tc]]
+// CHECK-NEXT: br i1 %omp_omp.loop.cmp, label %omp_omp.loop.body, label %omp_omp.loop.exit
+// CHECK-EMPTY:
+// CHECK-NEXT: omp_omp.loop.body:
+// CHECK-NEXT: br label %omp.loop.region
+// CHECK-EMPTY:
+// CHECK-NEXT: omp.loop.region:
+// CHECK-NEXT: store float 4.200000e+01, ptr %[[ptr]], align 4
+// CHECK-NEXT: br label %omp.region.cont
+// CHECK-EMPTY:
+// CHECK-NEXT: omp.region.cont:
+// CHECK-NEXT: br label %omp_omp.loop.inc
+// CHECK-EMPTY:
+// CHECK-NEXT: omp_omp.loop.inc:
+// CHECK-NEXT: %omp_omp.loop.next = add nuw i32 %omp_omp.loop.iv, 1
+// CHECK-NEXT: br label %omp_omp.loop.header
+// CHECK-EMPTY:
+// CHECK-NEXT: omp_omp.loop.exit:
+// CHECK-NEXT: br label %omp_omp.loop.after
+// CHECK-EMPTY:
+// CHECK-NEXT: omp_omp.loop.after:
+// CHECK-NEXT: ret void
+// CHECK-NEXT: }
+llvm.func @anon_loop(%ptr: !llvm.ptr, %tc : i32) -> () {
+ omp.canonical_loop %iv : i32 in range(%tc) {
+ %val = llvm.mlir.constant(42.0 : f32) : f32
+ llvm.store %val, %ptr : f32, !llvm.ptr
+ omp.terminator
+ }
+ llvm.return
+}
+
+
+
+// CHECK-LABEL: define void @trivial_loop(
+// CHECK-SAME: ptr %[[ptr:.+]],
+// CHECK-SAME: i32 %[[tc:.+]]) {
+// CHECK-NEXT: br label %omp_omp.loop.preheader
+// CHECK-EMPTY:
+// CHECK-NEXT: omp_omp.loop.preheader:
+// CHECK-NEXT: br label %omp_omp.loop.header
+// CHECK-EMPTY:
+// CHECK-NEXT: omp_omp.loop.header:
+// CHECK-NEXT: %omp_omp.loop.iv = phi i32 [ 0, %omp_omp.loop.preheader ], [ %omp_omp.loop.next, %omp_omp.loop.inc ]
+// CHECK-NEXT: br label %omp_omp.loop.cond
+// CHECK-EMPTY:
+// CHECK-NEXT: omp_omp.loop.cond:
+// CHECK-NEXT: %omp_omp.loop.cmp = icmp ult i32 %omp_omp.loop.iv, %[[tc]]
+// CHECK-NEXT: br i1 %omp_omp.loop.cmp, label %omp_omp.loop.body, label %omp_omp.loop.exit
+// CHECK-EMPTY:
+// CHECK-NEXT: omp_omp.loop.body:
+// CHECK-NEXT: br label %omp.loop.region
+// CHECK-EMPTY:
+// CHECK-NEXT: omp.loop.region:
+// CHECK-NEXT: store float 4.200000e+01, ptr %[[ptr]], align 4
+// CHECK-NEXT: br label %omp.region.cont
+// CHECK-EMPTY:
+// CHECK-NEXT: omp.region.cont:
+// CHECK-NEXT: br label %omp_omp.loop.inc
+// CHECK-EMPTY:
+// CHECK-NEXT: omp_omp.loop.inc:
+// CHECK-NEXT: %omp_omp.loop.next = add nuw i32 %omp_omp.loop.iv, 1
+// CHECK-NEXT: br label %omp_omp.loop.header
+// CHECK-EMPTY:
+// CHECK-NEXT: omp_omp.loop.exit:
+// CHECK-NEXT: br label %omp_omp.loop.after
+// CHECK-EMPTY:
+// CHECK-NEXT: omp_omp.loop.after:
+// CHECK-NEXT: ret void
+// CHECK-NEXT: }
+llvm.func @trivial_loop(%ptr: !llvm.ptr, %tc : i32) -> () {
+ %cli = omp.new_cli
+ omp.canonical_loop(%cli) %iv : i32 in range(%tc) {
+ %val = llvm.mlir.constant(42.0 : f32) : f32
+ llvm.store %val, %ptr : f32, !llvm.ptr
+ omp.terminator
+ }
+ llvm.return
+}
+
+
+// CHECK-LABEL: define void @nested_loop(
+// CHECK-SAME: ptr %[[ptr:.+]], i32 %[[outer_tc:.+]], i32 %[[inner_tc:.+]]) {
+// CHECK-NEXT: br label %omp_omp.loop.preheader
+// CHECK-EMPTY:
+// CHECK-NEXT: omp_omp.loop.preheader:
+// CHECK-NEXT: br label %omp_omp.loop.header
+// CHECK-EMPTY:
+// CHECK-NEXT: omp_omp.loop.header:
+// CHECK-NEXT: %omp_omp.loop.iv = phi i32 [ 0, %omp_omp.loop.preheader ], [ %omp_omp.loop.next, %omp_omp.loop.inc ]
+// CHECK-NEXT: br label %omp_omp.loop.cond
+// CHECK-EMPTY:
+// CHECK-NEXT: omp_omp.loop.cond:
+// CHECK-NEXT: %omp_omp.loop.cmp = icmp ult i32 %omp_omp.loop.iv, %[[outer_tc]]
+// CHECK-NEXT: br i1 %omp_omp.loop.cmp, label %omp_omp.loop.body, label %omp_omp.loop.exit
+// CHECK-EMPTY:
+// CHECK-NEXT: omp_omp.loop.body:
+// CHECK-NEXT: br label %omp.loop.region
+// CHECK-EMPTY:
+// CHECK-NEXT: omp.loop.region:
+// CHECK-NEXT: br label %omp_omp.loop.preheader1
+// CHECK-EMPTY:
+// CHECK-NEXT: omp_omp.loop.preheader1:
+// CHECK-NEXT: br label %omp_omp.loop.header2
+// CHECK-EMPTY:
+// CHECK-NEXT: omp_omp.loop.header2:
+// CHECK-NEXT: %omp_omp.loop.iv8 = phi i32 [ 0, %omp_omp.loop.preheader1 ], [ %omp_omp.loop.next10, %omp_omp.loop.inc5 ]
+// CHECK-NEXT: br label %omp_omp.loop.cond3
+// CHECK-EMPTY:
+// CHECK-NEXT: omp_omp.loop.cond3:
+// CHECK-NEXT: %omp_omp.loop.cmp9 = icmp ult i32 %omp_omp.loop.iv8, %[[inner_tc]]
+// CHECK-NEXT: br i1 %omp_omp.loop.cmp9, label %omp_omp.loop.body4, label %omp_omp.loop.exit6
+// CHECK-EMPTY:
+// CHECK-NEXT: omp_omp.loop.body4:
+// CHECK-NEXT: br label %omp.loop.region12
+// CHECK-EMPTY:
+// CHECK-NEXT: omp.loop.region12:
+// CHECK-NEXT: store float 4.200000e+01, ptr %[[ptr]], align 4
+// CHECK-NEXT: br label %omp.region.cont11
+// CHECK-EMPTY:
+// CHECK-NEXT: omp.region.cont11:
+// CHECK-NEXT: br label %omp_omp.loop.inc5
+// CHECK-EMPTY:
+// CHECK-NEXT: omp_omp.loop.inc5:
+// CHECK-NEXT: %omp_omp.loop.next10 = add nuw i32 %omp_omp.loop.iv8, 1
+// CHECK-NEXT: br label %omp_omp.loop.header2
+// CHECK-EMPTY:
+// CHECK-NEXT: omp_omp.loop.exit6:
+// CHECK-NEXT: br label %omp_omp.loop.after7
+// CHECK-EMPTY:
+// CHECK-NEXT: omp_omp.loop.after7:
+// CHECK-NEXT: br label %omp.region.cont
+// CHECK-EMPTY:
+// CHECK-NEXT: omp.region.cont:
+// CHECK-NEXT: br label %omp_omp.loop.inc
+// CHECK-EMPTY:
+// CHECK-NEXT: omp_omp.loop.inc:
+// CHECK-NEXT: %omp_omp.loop.next = add nuw i32 %omp_omp.loop.iv, 1
+// CHECK-NEXT: br label %omp_omp.loop.header
+// CHECK-EMPTY:
+// CHECK-NEXT: omp_omp.loop.exit:
+// CHECK-NEXT: br label %omp_omp.loop.after
+// CHECK-EMPTY:
+// CHECK-NEXT: omp_omp.loop.after:
+// CHECK-NEXT: ret void
+// CHECK-NEXT: }
+llvm.func @nested_loop(%ptr: !llvm.ptr, %outer_tc : i32, %inner_tc : i32) -> () {
+ %outer_cli = omp.new_cli
+ %inner_cli = omp.new_cli
+ omp.canonical_loop(%outer_cli) %outer_iv : i32 in range(%outer_tc) {
+ omp.canonical_loop(%inner_cli) %inner_iv : i32 in range(%inner_tc) {
+ %val = llvm.mlir.constant(42.0 : f32) : f32
+ llvm.store %val, %ptr : f32, !llvm.ptr
+ omp.terminator
+ }
+ omp.terminator
+ }
+ llvm.return
+}
diff --git a/mlir/test/Target/LLVMIR/openmp-cli-unroll-heuristic01.mlir b/mlir/test/Target/LLVMIR/openmp-cli-unroll-heuristic01.mlir
new file mode 100644
index 0000000000000..0f0448e15f983
--- /dev/null
+++ b/mlir/test/Target/LLVMIR/openmp-cli-unroll-heuristic01.mlir
@@ -0,0 +1,56 @@
+// Test lowering of the omp.unroll_heuristic
+// RUN: mlir-translate -mlir-to-llvmir %s | FileCheck %s
+
+
+// CHECK-LABEL: define void @unroll_heuristic_trivial_loop(
+// CHECK-SAME: ptr %[[ptr:.+]], i32 %[[tc:.+]]) {
+// CHECK-NEXT: br label %omp_omp.loop.preheader
+// CHECK-EMPTY:
+// CHECK-NEXT: omp_omp.loop.preheader:
+// CHECK-NEXT: br label %omp_omp.loop.header
+// CHECK-EMPTY:
+// CHECK-NEXT: omp_omp.loop.header:
+// CHECK-NEXT: %omp_omp.loop.iv = phi i32 [ 0, %omp_omp.loop.preheader ], [ %omp_omp.loop.next, %omp_omp.loop.inc ]
+// CHECK-NEXT: br label %omp_omp.loop.cond
+// CHECK-EMPTY:
+// CHECK-NEXT: omp_omp.loop.cond:
+// CHECK-NEXT: %omp_omp.loop.cmp = icmp ult i32 %omp_omp.loop.iv, %[[tc]]
+// CHECK-NEXT: br i1 %omp_omp.loop.cmp, label %omp_omp.loop.body, label %omp_omp.loop.exit
+// CHECK-EMPTY:
+// CHECK-NEXT: omp_omp.loop.body:
+// CHECK-NEXT: br label %omp.loop.region
+// CHECK-EMPTY:
+// CHECK-NEXT: omp.loop.region:
+// CHECK-NEXT: store float 4.200000e+01, ptr %[[ptr]], align 4
+// CHECK-NEXT: br label %omp.region.cont
+// CHECK-EMPTY:
+// CHECK-NEXT: omp.region.cont:
+// CHECK-NEXT: br label %omp_omp.loop.inc
+// CHECK-EMPTY:
+// CHECK-NEXT: omp_omp.loop.inc:
+// CHECK-NEXT: %omp_omp.loop.next = add nuw i32 %omp_omp.loop.iv, 1
+// CHECK-NEXT: br label %omp_omp.loop.header, !llvm.loop ![[$MD1:[0-9]+]]
+// CHECK-EMPTY:
+// CHECK-NEXT: omp_omp.loop.exit:
+// CHECK-NEXT: br label %omp_omp.loop.after
+// CHECK-EMPTY:
+// CHECK-NEXT: omp_omp.loop.after:
+// CHECK-NEXT: ret void
+// CHECK-NEXT: }
+llvm.func @unroll_heuristic_trivial_loop(%ptr: !llvm.ptr, %tc: i32) -> () {
+ %literal_cli = omp.new_cli
+ omp.canonical_loop(%literal_cli) %iv : i32 in range(%tc) {
+ %val = llvm.mlir.constant(42.0 : f32) : f32
+ llvm.store %val, %ptr : f32, !llvm.ptr
+ omp.terminator
+ }
+ omp.unroll_heuristic(%literal_cli)
+ llvm.return
+}
+
+
+// Start of metadata
+// CHECK-LABEL: !llvm.module.flags
+
+// CHECK: ![[$MD1]] = distinct !{![[$MD1]], ![[$MD2:[0-9]+]]}
+// CHECK: ![[$MD2]] = !{!"llvm.loop.unroll.enable"}
diff --git a/mlir/test/Target/LLVMIR/openmp-cli-unroll-heuristic02.mlir b/mlir/test/Target/LLVMIR/openmp-cli-unroll-heuristic02.mlir
new file mode 100644
index 0000000000000..f82b4990e378e
--- /dev/null
+++ b/mlir/test/Target/LLVMIR/openmp-cli-unroll-heuristic02.mlir
@@ -0,0 +1,93 @@
+// Test lowering of the omp.unroll_heuristic
+// RUN: mlir-translate -mlir-to-llvmir %s | FileCheck %s
+
+
+// CHECK-LABEL: define void @unroll_heuristic_nested_loop(
+// CHECK-SAME: ptr %[[ptr:.+]], i32 %[[outer_tc:.+]], i32 %[[inner_tc:.+]]) {
+// CHECK-NEXT: br label %omp_omp.loop.preheader
+// CHECK-EMPTY:
+// CHECK-NEXT: omp_omp.loop.preheader:
+// CHECK-NEXT: br label %omp_omp.loop.header
+// CHECK-EMPTY:
+// CHECK-NEXT: omp_omp.loop.header:
+// CHECK-NEXT: %omp_omp.loop.iv = phi i32 [ 0, %omp_omp.loop.preheader ], [ %omp_omp.loop.next, %omp_omp.loop.inc ]
+// CHECK-NEXT: br label %omp_omp.loop.cond
+// CHECK-EMPTY:
+// CHECK-NEXT: omp_omp.loop.cond:
+// CHECK-NEXT: %omp_omp.loop.cmp = icmp ult i32 %omp_omp.loop.iv, %[[outer_tc]]
+// CHECK-NEXT: br i1 %omp_omp.loop.cmp, label %omp_omp.loop.body, label %omp_omp.loop.exit
+// CHECK-EMPTY:
+// CHECK-NEXT: omp_omp.loop.body:
+// CHECK-NEXT: br label %omp.loop.region
+// CHECK-EMPTY:
+// CHECK-NEXT: omp.loop.region:
+// CHECK-NEXT: br label %omp_omp.loop.preheader1
+// CHECK-EMPTY:
+// CHECK-NEXT: omp_omp.loop.preheader1:
+// CHECK-NEXT: br label %omp_omp.loop.header2
+// CHECK-EMPTY:
+// CHECK-NEXT: omp_omp.loop.header2:
+// CHECK-NEXT: %omp_omp.loop.iv8 = phi i32 [ 0, %omp_omp.loop.preheader1 ], [ %omp_omp.loop.next10, %omp_omp.loop.inc5 ]
+// CHECK-NEXT: br label %omp_omp.loop.cond3
+// CHECK-EMPTY:
+// CHECK-NEXT: omp_omp.loop.cond3:
+// CHECK-NEXT: %omp_omp.loop.cmp9 = icmp ult i32 %omp_omp.loop.iv8, %[[inner_tc]]
+// CHECK-NEXT: br i1 %omp_omp.loop.cmp9, label %omp_omp.loop.body4, label %omp_omp.loop.exit6
+// CHECK-EMPTY:
+// CHECK-NEXT: omp_omp.loop.body4:
+// CHECK-NEXT: br label %omp.loop.region12
+// CHECK-EMPTY:
+// CHECK-NEXT: omp.loop.region12:
+// CHECK-NEXT: store float 4.200000e+01, ptr %[[ptr]], align 4
+// CHECK-NEXT: br label %omp.region.cont11
+// CHECK-EMPTY:
+// CHECK-NEXT: omp.region.cont11:
+// CHECK-NEXT: br label %omp_omp.loop.inc5
+// CHECK-EMPTY:
+// CHECK-NEXT: omp_omp.loop.inc5:
+// CHECK-NEXT: %omp_omp.loop.next10 = add nuw i32 %omp_omp.loop.iv8, 1
+// CHECK-NEXT: br label %omp_omp.loop.header2, !llvm.loop ![[$MD1:[0-9]+]]
+// CHECK-EMPTY:
+// CHECK-NEXT: omp_omp.loop.exit6:
+// CHECK-NEXT: br label %omp_omp.loop.after7
+// CHECK-EMPTY:
+// CHECK-NEXT: omp_omp.loop.after7:
+// CHECK-NEXT: br label %omp.region.cont
+// CHECK-EMPTY:
+// CHECK-NEXT: omp.region.cont:
+// CHECK-NEXT: br label %...
[truncated]
|
tblah
approved these changes
Jul 9, 2025
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Support for translating the operations introduced in #144785 to LLVM-IR.
In order to keep the lowering simple,
OpenMPIRBuider::unrollLoopHeuristicis applied when encountering theomp.unroll_heuristicop. As a result, the operation that unrolling is applied to (omp.canonical_loop) must have been emitted before even though logically there is no such requirement.Eventually, all transformations on a loop must be applied directly after emitting
omp.canonical_loop, i.e. future transformations must be looked-up when encounteringomp.canonical_loopitself. This is because many OpenMPIRBuilder methods (e.g.createParallel) expect all the region code to be emitted withing a callback. In the case ofcreateParallel, the region code is getting outlined into a new function. Therefore, making the operation requirement an IR order would not make the implementation any easier.