[flang-commits] [flang] [llvm] [flang][OpenMP] Decompose compound constructs, do recursive lowering (PR #90098)

[Krzysztof Parzyszek via flang-commits]

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@@ -0,0 +1,404 @@
+//===- ConstructCompositionT.h -- Composing compound constructs -----------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+// Given a list of leaf construct, each with a set of clauses, generate the
+// compound construct whose leaf constructs are the given list, and whose clause
+// list is the merged lists of individual leaf clauses.
+//
+// *** At the moment it assumes that the individual constructs and their clauses
+// *** are a subset of those created by splitting a valid compound construct.
+//===----------------------------------------------------------------------===//
+#ifndef LLVM_FRONTEND_OPENMP_CONSTRUCTCOMPOSITIONT_H
+#define LLVM_FRONTEND_OPENMP_CONSTRUCTCOMPOSITIONT_H
+
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/BitVector.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/Frontend/OpenMP/ClauseT.h"
+#include "llvm/Frontend/OpenMP/OMP.h"
+
+#include <iterator>
+#include <optional>
+#include <tuple>
+#include <unordered_map>
+#include <unordered_set>
+#include <utility>
+
+namespace detail {
+template <typename T> struct trivial_hash {
+  size_t operator()(const T &) const { return 1u; }
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kparzysz wrote:

Unless you have thousands of clauses, then no.  It's just like iterating over them and using `==` to see if they are equal.  In fact, only clauses of the same type (i.e. repeatable ones) will be present in each set, so the number of elements in each set should be small.  I only need the hash to be able to add them to an unordered set.

https://github.com/llvm/llvm-project/pull/90098