[flang-commits] [flang] [flang][OpenMP] Add `--openmp-enable-delayed-privatization-staging` flag (PR #94749)

[Kareem Ergawy via flang-commits]

https://github.com/ergawy created https://github.com/llvm/llvm-project/pull/94749

Adds a new flag for delayed privatization to differentiate between features for which delayed privatization is fully supported vs. features with partial support. This enables use roll out delayed privatization and test it in the wild for completely supported constructs while keeping it switched off for partially supported ones. Which allows us to discover the issues early on rather than wait for all constructs to be supported.

>From 439a17a87b58d8ff0999f15763c975733a9c4dc0 Mon Sep 17 00:00:00 2001
From: ergawy <kareem.ergawy at amd.com>
Date: Fri, 7 Jun 2024 03:41:55 -0500
Subject: [PATCH] [flang][OpenMP] Add
 `--openmp-enable-delayed-privatization-staging` flag

Adds a new flag for delayed privatization to differentiate between
features for which delayed privatization is fully supported vs. features
with partial support. This enables use roll out delayed privatization and
test it in the wild for completely supported constructs while keeping it
switched off for partially supported ones. Which allows us to discover the
issues early on rather than wait for all constructs to be supported.
---
 flang/lib/Lower/OpenMP/OpenMP.cpp                           | 2 +-
 flang/lib/Lower/OpenMP/Utils.cpp                            | 6 ++++++
 flang/lib/Lower/OpenMP/Utils.h                              | 1 +
 .../DelayedPrivatization/target-private-allocatable.f90     | 4 ++--
 .../target-private-multiple-variables.f90                   | 4 ++--
 .../OpenMP/DelayedPrivatization/target-private-simple.f90   | 4 ++--
 6 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/flang/lib/Lower/OpenMP/OpenMP.cpp b/flang/lib/Lower/OpenMP/OpenMP.cpp
index 184c43ff9fe91..6b391e11beb48 100644
--- a/flang/lib/Lower/OpenMP/OpenMP.cpp
+++ b/flang/lib/Lower/OpenMP/OpenMP.cpp
@@ -1114,7 +1114,7 @@ static void genTargetClauses(
                                          llvm::omp::Directive::OMPD_target);
 
   // `target private(..)` is only supported in delayed privatization mode.
-  if (!enableDelayedPrivatization)
+  if (!enableDelayedPrivatizationStaging)
     cp.processTODO<clause::Private>(loc, llvm::omp::Directive::OMPD_target);
 }
 
diff --git a/flang/lib/Lower/OpenMP/Utils.cpp b/flang/lib/Lower/OpenMP/Utils.cpp
index da94352a84a7c..36d96f37ff36a 100644
--- a/flang/lib/Lower/OpenMP/Utils.cpp
+++ b/flang/lib/Lower/OpenMP/Utils.cpp
@@ -36,6 +36,12 @@ llvm::cl::opt<bool> enableDelayedPrivatization(
         "Emit `[first]private` variables as clauses on the MLIR ops."),
     llvm::cl::init(false));
 
+llvm::cl::opt<bool> enableDelayedPrivatizationStaging(
+    "openmp-enable-delayed-privatization-staging",
+    llvm::cl::desc("For partially supported constructs, emit `[first]private` "
+                   "variables as clauses on the MLIR ops."),
+    llvm::cl::init(false));
+
 namespace Fortran {
 namespace lower {
 namespace omp {
diff --git a/flang/lib/Lower/OpenMP/Utils.h b/flang/lib/Lower/OpenMP/Utils.h
index d20f9187640f0..0b4fe9044bfa7 100644
--- a/flang/lib/Lower/OpenMP/Utils.h
+++ b/flang/lib/Lower/OpenMP/Utils.h
@@ -17,6 +17,7 @@
 
 extern llvm::cl::opt<bool> treatIndexAsSection;
 extern llvm::cl::opt<bool> enableDelayedPrivatization;
+extern llvm::cl::opt<bool> enableDelayedPrivatizationStaging;
 
 namespace fir {
 class FirOpBuilder;
diff --git a/flang/test/Lower/OpenMP/DelayedPrivatization/target-private-allocatable.f90 b/flang/test/Lower/OpenMP/DelayedPrivatization/target-private-allocatable.f90
index 17a28c6a5ab7d..a27de1152ce17 100644
--- a/flang/test/Lower/OpenMP/DelayedPrivatization/target-private-allocatable.f90
+++ b/flang/test/Lower/OpenMP/DelayedPrivatization/target-private-allocatable.f90
@@ -1,8 +1,8 @@
 ! Tests delayed privatization for `targets ... private(..)` for allocatables.
 
-! RUN: %flang_fc1 -emit-hlfir -fopenmp -mmlir --openmp-enable-delayed-privatization \
+! RUN: %flang_fc1 -emit-hlfir -fopenmp -mmlir --openmp-enable-delayed-privatization-staging \
 ! RUN:   -o - %s 2>&1 | FileCheck %s
-! RUN: bbc -emit-hlfir -fopenmp --openmp-enable-delayed-privatization -o - %s 2>&1 \
+! RUN: bbc -emit-hlfir -fopenmp --openmp-enable-delayed-privatization-staging -o - %s 2>&1 \
 ! RUN:   | FileCheck %s
 
 subroutine target_allocatable
diff --git a/flang/test/Lower/OpenMP/DelayedPrivatization/target-private-multiple-variables.f90 b/flang/test/Lower/OpenMP/DelayedPrivatization/target-private-multiple-variables.f90
index 8682a420e89d9..6e8282b2af625 100644
--- a/flang/test/Lower/OpenMP/DelayedPrivatization/target-private-multiple-variables.f90
+++ b/flang/test/Lower/OpenMP/DelayedPrivatization/target-private-multiple-variables.f90
@@ -1,8 +1,8 @@
 ! Tests delayed privatization for `targets ... private(..)` for allocatables.
 
-! RUN: %flang_fc1 -emit-hlfir -fopenmp -mmlir --openmp-enable-delayed-privatization \
+! RUN: %flang_fc1 -emit-hlfir -fopenmp -mmlir --openmp-enable-delayed-privatization-staging \
 ! RUN:   -o - %s 2>&1 | FileCheck %s
-! RUN: bbc -emit-hlfir -fopenmp --openmp-enable-delayed-privatization -o - %s 2>&1 \
+! RUN: bbc -emit-hlfir -fopenmp --openmp-enable-delayed-privatization-staging -o - %s 2>&1 \
 ! RUN:   | FileCheck %s
 
 subroutine target_allocatable(lb, ub, l)
diff --git a/flang/test/Lower/OpenMP/DelayedPrivatization/target-private-simple.f90 b/flang/test/Lower/OpenMP/DelayedPrivatization/target-private-simple.f90
index 94edeaa5a7ef1..524e973780c49 100644
--- a/flang/test/Lower/OpenMP/DelayedPrivatization/target-private-simple.f90
+++ b/flang/test/Lower/OpenMP/DelayedPrivatization/target-private-simple.f90
@@ -1,8 +1,8 @@
 ! Tests delayed privatization for `targets ... private(..)` for simple variables.
 
-! RUN: %flang_fc1 -emit-hlfir -fopenmp -mmlir --openmp-enable-delayed-privatization \
+! RUN: %flang_fc1 -emit-hlfir -fopenmp -mmlir --openmp-enable-delayed-privatization-staging \
 ! RUN:   -o - %s 2>&1 | FileCheck %s
-! RUN: bbc -emit-hlfir -fopenmp --openmp-enable-delayed-privatization -o - %s 2>&1 \
+! RUN: bbc -emit-hlfir -fopenmp --openmp-enable-delayed-privatization-staging -o - %s 2>&1 \
 ! RUN:   | FileCheck %s
 
 subroutine target_simple