From e7d37742a2a584fef9002778b33f9453647ab43c Mon Sep 17 00:00:00 2001
From: Sourabh Singh Tomar <SourabhSingh.Tomar@amd.com>
Date: Fri, 23 Oct 2020 20:29:12 +0530
Subject: [PATCH] [flang][OpenMP] Upstream lowering of OpenMP `Flush` construct

Note: This patch reflects the work that can be upstreamed from PR's(merged):

- https://github.com/flang-compiler/f18-llvm-project/pull/476

Reviewed By: kiranchandramohan, clementval

Differential Revision: https://reviews.llvm.org/D90048
---
 flang/lib/Lower/OpenMP.cpp | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/flang/lib/Lower/OpenMP.cpp b/flang/lib/Lower/OpenMP.cpp
index 9c9c0a298dd6e..5b69800176ea7 100644
--- a/flang/lib/Lower/OpenMP.cpp
+++ b/flang/lib/Lower/OpenMP.cpp
@@ -104,7 +104,16 @@ genOMP(Fortran::lower::AbstractConverter &converter,
             genOMP(converter, eval, simpleStandaloneConstruct);
           },
           [&](const Fortran::parser::OpenMPFlushConstruct &flushConstruct) {
-            TODO();
+            SmallVector<Value, 4> operandRange;
+            if (const auto &ompObjectList =
+                    std::get<std::optional<Fortran::parser::OmpObjectList>>(
+                        flushConstruct.t))
+              genObjectList(*ompObjectList, converter, operandRange);
+            if (std::get<std::optional<Fortran::parser::OmpFlushMemoryClause>>(
+                    flushConstruct.t))
+              TODO("Handle OmpFlushMemoryClause");
+            converter.getFirOpBuilder().create<mlir::omp::FlushOp>(
+                converter.getCurrentLocation(), operandRange);
           },
           [&](const Fortran::parser::OpenMPCancelConstruct &cancelConstruct) {
             TODO("");