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

[Sergio Afonso 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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skatrak wrote:

Does this not introduce a significant performance penalty when all hashes in the unordered set will be guaranteed to collide?

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