[flang-commits] [flang] [llvm] [mlir] [MLIR][OpenMP] Lowering nontemporal clause to LLVM IR for SIMD directive (PR #118751)

[Tom Eccles via flang-commits]

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@@ -0,0 +1,71 @@
+//===- LowerNontemporal.cpp -------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+// Add nontemporal attributes to load and stores of variables marked as
+// nontemporal.
+//
+//===----------------------------------------------------------------------===//
+#include "flang/Optimizer/Dialect/FIROpsSupport.h"
+#include "flang/Optimizer/OpenMP/Passes.h"
+#include "mlir/Dialect/OpenMP/OpenMPDialect.h"
+using namespace mlir;
+namespace flangomp {
+#define GEN_PASS_DEF_LOWERNONTEMPORALPASS
+#include "flang/Optimizer/OpenMP/Passes.h.inc"
+} // namespace flangomp
+namespace {
+class LowerNontemporalPass
+    : public flangomp::impl::LowerNontemporalPassBase<LowerNontemporalPass> {
+  void addNonTemporalAttr(omp::SimdOp simdOp) {
+    if (!simdOp.getNontemporalVars().empty()) {
+      llvm::SmallVector<mlir::Value> nontemporalOrigVars;
+      mlir::OperandRange nontemporals = simdOp.getNontemporalVars();
+      for (mlir::Value nontemporal : nontemporals) {
+        nontemporalOrigVars.push_back(nontemporal);
+      }
+      std::function<mlir::Value(mlir::Value)> getBaseOperand =
+          [&](mlir::Value operand) -> mlir::Value {
+        if (mlir::isa<fir::DeclareOp>(operand.getDefiningOp()))
+          return operand;
+        else if (auto arrayCoorOp = llvm::dyn_cast<fir::ArrayCoorOp>(
+                     operand.getDefiningOp())) {
+          return getBaseOperand(arrayCoorOp.getMemref());
+        } else if (auto boxAddrOp = llvm::dyn_cast<fir::BoxAddrOp>(
+                       operand.getDefiningOp())) {
+          return getBaseOperand(boxAddrOp.getVal());
+        } else if (auto loadOp =
+                       llvm::dyn_cast<fir::LoadOp>(operand.getDefiningOp())) {
+          return getBaseOperand(loadOp.getMemref());
+        } else {
+          return operand;
+        }
+      };
+      simdOp->walk([&](Operation *op) {
+        mlir::Value Operand = nullptr;
+        if (auto loadOp = llvm::dyn_cast<fir::LoadOp>(op)) {
+          Operand = loadOp.getMemref();
+        } else if (auto storeOp = llvm::dyn_cast<fir::StoreOp>(op)) {
+          Operand = storeOp.getMemref();
+        }
+        if (Operand && !(fir::isAllocatableType(Operand.getType()) ||
+                         fir::isPointerType((Operand.getType())))) {
+          Operand = getBaseOperand(Operand);
+          if (is_contained(nontemporalOrigVars, Operand)) {
+            // Set the attribute
+            op->setAttr("nontemporal", UnitAttr::get(op->getContext()));
----------------
tblah wrote:

Okay yeah I guess as this is just a UnitAttr it isn't worth defining it carefully in the dialect.

So yes adding to fir.load and fir.store sounds okay to me. Please do that in a separate PR so it is to get review from other maintainers of FIR.

https://github.com/llvm/llvm-project/pull/118751