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

[Tom Eccles via llvm-commits]

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@@ -0,0 +1,76 @@
+//===- 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())
+      return;
+
+    std::function<mlir::Value(mlir::Value)> getBaseOperand =
+        [&](mlir::Value operand) -> mlir::Value {
+      if (mlir::isa<mlir::BlockArgument>(operand) ||
+          (mlir::isa<fir::AllocaOp>(operand.getDefiningOp())) ||
+          (mlir::isa<fir::DeclareOp>(operand.getDefiningOp())))
+        return operand;
+
+      Operation *definingOp = operand.getDefiningOp();
+      if (definingOp) {
+        for (Value srcOp : definingOp->getOperands()) {
+          return getBaseOperand(srcOp);
+        }
+      }
----------------
tblah wrote:

Which operation(s) are you intending to scan through here? I'm worried that the first operand on the defining op might not be the right one to return for all possible operations.

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