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

Author: ergawy

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);
 }
 

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 {

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;

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

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)

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