[flang-commits] [flang] aec735c - [Flang][OpenMP][MLIR] Fix common block mapping for regular and declare target link (#91829)

[via flang-commits]

Author: agozillon
Date: 2024-06-25T20:54:04+02:00
New Revision: aec735cf476c3975b026aa79fa40dda06a27fac3

URL: https://github.com/llvm/llvm-project/commit/aec735cf476c3975b026aa79fa40dda06a27fac3
DIFF: https://github.com/llvm/llvm-project/commit/aec735cf476c3975b026aa79fa40dda06a27fac3.diff

LOG: [Flang][OpenMP][MLIR] Fix common block mapping for regular and declare target link (#91829)

This PR attempts to fix common block mapping for regular mapping of
these types as well as when they have been marked as "declare target
link". This PR should allow correct mapping of both the members of a
common block and the full common block via its block symbol.

The main changes were some adjustments to the Fortran OpenMP lowering to
HLFIR/FIR, the lowering of the LLVM+OpenMP dialect to LLVM-IR and
adjustments to the way the we handle target kernel map argument
rebinding inside of the OMPIRBuilder.

For the Fortran OpenMP lowering were two changes, one to prevent the
implicit capture of common block members when the common block symbol
itself has been marked and the other creates intermediate member access
inside of the target region to be used in-place of those external to the
target region, this prevents external usages breaking the
IsolatedFromAbove pact.

In the latter case, there was an adjustment to the size calculation for
types to better handle cases where we pass an array as the type of a map
(as opposed to the bounds and the type of the element), which occurs in
the case of common blocks. There is also some adjustment to how
handleDeclareTargetMapVar handles renaming of declare target symbols in
the module to the reference pointer, now it will only apply to those
within the kernel that is currently being generated and we also perform
a modification to replace constants with instructions as necessary as we
cannot replace these with our reference pointer (non-constant and
constants do not mix nicely).

In the case of the OpenMPIRBuilder some changes were made to defer
global symbol rebinding to kernel arguments until all other arguments
have been rebound. This makes sure we do not replace uses that may refer
to the global (e.g. a GEP) but are themselves actually a separate
argument that needs bound.

Currently "declare target to" still needs some work, but this may be the
case for all types in conjunction with "declare target to" at the
moment.

Added: 
    flang/test/Lower/OpenMP/common-block-map.f90
    mlir/test/Target/LLVMIR/omptarget-fortran-common-block-host.mlir
    offload/test/offloading/fortran/target-map-all-common-block-members.f90
    offload/test/offloading/fortran/target-map-common-block.f90
    offload/test/offloading/fortran/target-map-declare-target-link-common-block.f90
    offload/test/offloading/fortran/target-map-first-common-block-member.f90
    offload/test/offloading/fortran/target-map-mix-imp-exp-common-block-members.f90
    offload/test/offloading/fortran/target-map-second-common-block-member.f90

Modified: 
    flang/lib/Lower/OpenMP/OpenMP.cpp
    flang/test/Fir/convert-to-llvm-openmp-and-fir.fir
    flang/test/Integration/OpenMP/map-types-and-sizes.f90
    llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp
    mlir/lib/Target/LLVMIR/Dialect/OpenMP/OpenMPToLLVMIRTranslation.cpp

Removed: 
    


################################################################################
diff  --git a/flang/lib/Lower/OpenMP/OpenMP.cpp b/flang/lib/Lower/OpenMP/OpenMP.cpp
index 7d75e6f67dc1b..23f27496091a5 100644
--- a/flang/lib/Lower/OpenMP/OpenMP.cpp
+++ b/flang/lib/Lower/OpenMP/OpenMP.cpp
@@ -776,6 +776,33 @@ static void genBodyOfTargetDataOp(
   }
 }
 
+// This generates intermediate common block member accesses within a region
+// and then rebinds the members symbol to the intermediate accessors we have
+// generated so that subsequent code generation will utilise these instead.
+//
+// When the scope changes, the bindings to the intermediate accessors should
+// be dropped in place of the original symbol bindings.
+//
+// This is for utilisation with TargetOp.
+static void genIntermediateCommonBlockAccessors(
+    Fortran::lower::AbstractConverter &converter,
+    const mlir::Location &currentLocation, mlir::Region &region,
+    llvm::ArrayRef<const Fortran::semantics::Symbol *> mapSyms) {
+  for (auto [argIndex, argSymbol] : llvm::enumerate(mapSyms)) {
+    if (auto *details =
+            argSymbol->detailsIf<Fortran::semantics::CommonBlockDetails>()) {
+      for (auto obj : details->objects()) {
+        auto targetCBMemberBind = Fortran::lower::genCommonBlockMember(
+            converter, currentLocation, *obj, region.getArgument(argIndex));
+        fir::ExtendedValue sexv = converter.getSymbolExtendedValue(*obj);
+        fir::ExtendedValue targetCBExv =
+            getExtendedValue(sexv, targetCBMemberBind);
+        converter.bindSymbol(*obj, targetCBExv);
+      }
+    }
+  }
+}
+
 // This functions creates a block for the body of the targetOp's region. It adds
 // all the symbols present in mapSymbols as block arguments to this block.
 static void
@@ -955,6 +982,16 @@ genBodyOfTargetOp(lower::AbstractConverter &converter, lower::SymMap &symTable,
   // Create the insertion point after the marker.
   firOpBuilder.setInsertionPointAfter(undefMarker.getDefiningOp());
 
+  // If we map a common block using it's symbol e.g. map(tofrom: /common_block/)
+  // and accessing it's members within the target region, there is a large
+  // chance we will end up with uses external to the region accessing the common
+  // resolve these, we do so by generating new common block member accesses
+  // within the region, binding them to the member symbol for the scope of the
+  // region so that subsequent code generation within the region will utilise
+  // our new member accesses we have created.
+  genIntermediateCommonBlockAccessors(converter, currentLocation, region,
+                                      mapSyms);
+
   if (ConstructQueue::iterator next = std::next(item); next != queue.end()) {
     genOMPDispatch(converter, symTable, semaCtx, eval, currentLocation, queue,
                    next);
@@ -1670,6 +1707,13 @@ genTargetOp(lower::AbstractConverter &converter, lower::SymMap &symTable,
     if (dsp.getAllSymbolsToPrivatize().contains(&sym))
       return;
 
+    // if the symbol is part of an already mapped common block, do not make a
+    // map for it.
+    if (const Fortran::semantics::Symbol *common =
+            Fortran::semantics::FindCommonBlockContaining(sym.GetUltimate()))
+      if (llvm::find(mapSyms, common) != mapSyms.end())
+        return;
+
     if (llvm::find(mapSyms, &sym) == mapSyms.end()) {
       mlir::Value baseOp = converter.getSymbolAddress(sym);
       if (!baseOp)

diff  --git a/flang/test/Fir/convert-to-llvm-openmp-and-fir.fir b/flang/test/Fir/convert-to-llvm-openmp-and-fir.fir
index 396fbaeacf39f..8b62787bb3094 100644
--- a/flang/test/Fir/convert-to-llvm-openmp-and-fir.fir
+++ b/flang/test/Fir/convert-to-llvm-openmp-and-fir.fir
@@ -1006,3 +1006,77 @@ func.func @omp_map_info_nested_derived_type_explicit_member_conversion(%arg0 : !
 }
 
 // -----
+
+// CHECK-LABEL:  llvm.func @omp_map_common_block_using_common_block_symbol
+
+// CHECK: %[[ADDR_OF:.*]] = llvm.mlir.addressof @var_common_ : !llvm.ptr
+// CHECK: %[[CB_MAP:.*]] = omp.map.info var_ptr(%[[ADDR_OF]] : !llvm.ptr, !llvm.array<8 x i8>) map_clauses(tofrom) capture(ByRef) -> !llvm.ptr {name = "var_common"}
+// CHECK:    omp.target map_entries(%[[CB_MAP]] -> %[[ARG0:.*]] : !llvm.ptr) {
+// CHECK:    ^bb0(%[[ARG0]]: !llvm.ptr):
+// CHECK:      %[[VAR_2_OFFSET:.*]] = llvm.mlir.constant(4 : index) : i64
+// CHECK:      %[[VAR_1_OFFSET:.*]] = llvm.mlir.constant(0 : index) : i64
+// CHECK:      %{{.*}} = llvm.getelementptr %[[ARG0]][%[[VAR_1_OFFSET]]] : (!llvm.ptr, i64) -> !llvm.ptr, i8
+// CHECK:      %{{.*}} = llvm.getelementptr %[[ARG0]][%[[VAR_2_OFFSET]]] : (!llvm.ptr, i64) -> !llvm.ptr, i8
+
+func.func @omp_map_common_block_using_common_block_symbol() {
+  %0 = fir.address_of(@var_common_) : !fir.ref<!fir.array<8xi8>>
+  %1 = omp.map.info var_ptr(%0 : !fir.ref<!fir.array<8xi8>>, !fir.array<8xi8>) map_clauses(tofrom) capture(ByRef) -> !fir.ref<!fir.array<8xi8>> {name = "var_common"}
+  omp.target map_entries(%1 -> %arg0 : !fir.ref<!fir.array<8xi8>>) {
+  ^bb0(%arg0: !fir.ref<!fir.array<8xi8>>):
+    %c4 = arith.constant 4 : index
+    %c0 = arith.constant 0 : index
+    %c20_i32 = arith.constant 20 : i32
+    %2 = fir.convert %arg0 : (!fir.ref<!fir.array<8xi8>>) -> !fir.ref<!fir.array<?xi8>>
+    %3 = fir.coordinate_of %2, %c0 : (!fir.ref<!fir.array<?xi8>>, index) -> !fir.ref<i8>
+    %4 = fir.convert %3 : (!fir.ref<i8>) -> !fir.ref<i32>
+    %5 = fir.convert %arg0 : (!fir.ref<!fir.array<8xi8>>) -> !fir.ref<!fir.array<?xi8>>
+    %6 = fir.coordinate_of %5, %c4 : (!fir.ref<!fir.array<?xi8>>, index) -> !fir.ref<i8>
+    %7 = fir.convert %6 : (!fir.ref<i8>) -> !fir.ref<i32>
+    %8 = fir.load %4 : !fir.ref<i32>
+    %9 = arith.addi %8, %c20_i32 : i32
+    fir.store %9 to %7 : !fir.ref<i32>
+    omp.terminator
+  }
+  return
+}
+
+fir.global common @var_common_(dense<0> : vector<8xi8>) {alignment = 4 : i64} : !fir.array<8xi8>
+
+// -----
+
+// CHECK-LABEL:  llvm.func @omp_map_common_block_using_common_block_members
+
+// CHECK:    %[[VAR_2_OFFSET:.*]] = llvm.mlir.constant(4 : index) : i64
+// CHECK:    %[[VAR_1_OFFSET:.*]] = llvm.mlir.constant(0 : index) : i64
+// CHECK:    %[[ADDR_OF:.*]] = llvm.mlir.addressof @var_common_ : !llvm.ptr
+// CHECK:    %[[VAR_1_CB_GEP:.*]] = llvm.getelementptr %[[ADDR_OF]][%[[VAR_1_OFFSET]]] : (!llvm.ptr, i64) -> !llvm.ptr, i8
+// CHECK:    %[[VAR_2_CB_GEP:.*]] = llvm.getelementptr %[[ADDR_OF]][%[[VAR_2_OFFSET]]] : (!llvm.ptr, i64) -> !llvm.ptr, i8
+// CHECK:    %[[MAP_CB_VAR_1:.*]] = omp.map.info var_ptr(%[[VAR_1_CB_GEP]] : !llvm.ptr, i32) map_clauses(tofrom) capture(ByRef) -> !llvm.ptr {name = "var1"}
+// CHECK:    %[[MAP_CB_VAR_2:.*]] = omp.map.info var_ptr(%[[VAR_2_CB_GEP]] : !llvm.ptr, i32) map_clauses(tofrom) capture(ByRef) -> !llvm.ptr {name = "var2"}
+// CHECK:    omp.target map_entries(%[[MAP_CB_VAR_1]] -> %[[ARG0:.*]], %[[MAP_CB_VAR_2]] -> %[[ARG1:.*]] : !llvm.ptr, !llvm.ptr) {
+// CHECK:     ^bb0(%[[ARG0]]: !llvm.ptr, %[[ARG1]]: !llvm.ptr):
+
+func.func @omp_map_common_block_using_common_block_members() {
+  %c4 = arith.constant 4 : index
+  %c0 = arith.constant 0 : index
+  %0 = fir.address_of(@var_common_) : !fir.ref<!fir.array<8xi8>>
+  %1 = fir.convert %0 : (!fir.ref<!fir.array<8xi8>>) -> !fir.ref<!fir.array<?xi8>>
+  %2 = fir.coordinate_of %1, %c0 : (!fir.ref<!fir.array<?xi8>>, index) -> !fir.ref<i8>
+  %3 = fir.convert %2 : (!fir.ref<i8>) -> !fir.ref<i32>
+  %4 = fir.convert %0 : (!fir.ref<!fir.array<8xi8>>) -> !fir.ref<!fir.array<?xi8>>
+  %5 = fir.coordinate_of %4, %c4 : (!fir.ref<!fir.array<?xi8>>, index) -> !fir.ref<i8>
+  %6 = fir.convert %5 : (!fir.ref<i8>) -> !fir.ref<i32>
+  %7 = omp.map.info var_ptr(%3 : !fir.ref<i32>, i32) map_clauses(tofrom) capture(ByRef) -> !fir.ref<i32> {name = "var1"}
+  %8 = omp.map.info var_ptr(%6 : !fir.ref<i32>, i32) map_clauses(tofrom) capture(ByRef) -> !fir.ref<i32> {name = "var2"}
+  omp.target map_entries(%7 -> %arg0, %8 -> %arg1 : !fir.ref<i32>, !fir.ref<i32>) {
+  ^bb0(%arg0: !fir.ref<i32>, %arg1: !fir.ref<i32>):
+    %c10_i32 = arith.constant 10 : i32
+    %9 = fir.load %arg0 : !fir.ref<i32>
+    %10 = arith.muli %9, %c10_i32 : i32
+    fir.store %10 to %arg1 : !fir.ref<i32>
+    omp.terminator
+  }
+  return
+}
+
+fir.global common @var_common_(dense<0> : vector<8xi8>) {alignment = 4 : i64} : !fir.array<8xi8>

diff  --git a/flang/test/Integration/OpenMP/map-types-and-sizes.f90 b/flang/test/Integration/OpenMP/map-types-and-sizes.f90
index f3a20690f05a9..591be0b680a51 100644
--- a/flang/test/Integration/OpenMP/map-types-and-sizes.f90
+++ b/flang/test/Integration/OpenMP/map-types-and-sizes.f90
@@ -231,6 +231,31 @@ subroutine mapType_char
   !$omp end target
 end subroutine mapType_char
 
+!CHECK: @.offload_sizes{{.*}} = private unnamed_addr constant [1 x i64] [i64 8]
+!CHECK: @.offload_maptypes{{.*}} = private unnamed_addr constant [1 x i64] [i64 35]
+subroutine mapType_common_block
+  implicit none
+  common /var_common/ var1, var2
+  integer :: var1, var2
+!$omp target map(tofrom: /var_common/)
+  var1 = var1 + 20
+  var2 = var2 + 30
+!$omp end target
+end subroutine mapType_common_block
+
+!CHECK: @.offload_sizes{{.*}} = private unnamed_addr constant [2 x i64] [i64 4, i64 4]
+!CHECK: @.offload_maptypes{{.*}} = private unnamed_addr constant [2 x i64] [i64 35, i64 35]
+subroutine mapType_common_block_members
+  implicit none
+  common /var_common/ var1, var2
+  integer :: var1, var2
+
+!$omp target map(tofrom: var1, var2)
+  var2 = var1
+!$omp end target
+end subroutine mapType_common_block_members
+
+
 !CHECK-LABEL: define {{.*}} @{{.*}}maptype_ptr_explicit_{{.*}}
 !CHECK: %[[ALLOCA:.*]] = alloca { ptr, i64, i32, i8, i8, i8, i8 }, i64 1, align 8
 !CHECK: %[[ALLOCA_GEP:.*]] = getelementptr { ptr, i64, i32, i8, i8, i8, i8 }, ptr %[[ALLOCA]], i32 1
@@ -346,3 +371,19 @@ end subroutine mapType_char
 !CHECK: store ptr %[[ALLOCA]], ptr %[[BASE_PTR_ARR]], align 8
 !CHECK: %[[OFFLOAD_PTR_ARR:.*]] = getelementptr inbounds [1 x ptr], ptr %.offload_ptrs, i32 0, i32 0
 !CHECK: store ptr %[[ARR_OFF]], ptr %[[OFFLOAD_PTR_ARR]], align 8
+
+!CHECK-LABEL: define {{.*}} @{{.*}}maptype_common_block_{{.*}}
+!CHECK: %[[BASE_PTR_ARR:.*]] = getelementptr inbounds [1 x ptr], ptr %.offload_baseptrs, i32 0, i32 0
+!CHECK: store ptr @var_common_, ptr %[[BASE_PTR_ARR]], align 8
+!CHECK: %[[OFFLOAD_PTR_ARR:.*]] = getelementptr inbounds [1 x ptr], ptr %.offload_ptrs, i32 0, i32 0
+!CHECK: store ptr @var_common_, ptr %[[OFFLOAD_PTR_ARR]], align 8
+
+!CHECK-LABEL: define {{.*}} @{{.*}}maptype_common_block_members_{{.*}}
+!CHECK: %[[BASE_PTR_ARR:.*]] = getelementptr inbounds [2 x ptr], ptr %.offload_baseptrs, i32 0, i32 0
+!CHECK: store ptr @var_common_, ptr %[[BASE_PTR_ARR]], align 8
+!CHECK: %[[OFFLOAD_PTR_ARR:.*]] = getelementptr inbounds [2 x ptr], ptr %.offload_ptrs, i32 0, i32 0
+!CHECK: store ptr @var_common_, ptr %[[OFFLOAD_PTR_ARR]], align 8
+!CHECK: %[[BASE_PTR_ARR_1:.*]] = getelementptr inbounds [2 x ptr], ptr %.offload_baseptrs, i32 0, i32 1
+!CHECK: store ptr getelementptr (i8, ptr @var_common_, i64 4), ptr %[[BASE_PTR_ARR_1]], align 8
+!CHECK: %[[OFFLOAD_PTR_ARR_1:.*]] = getelementptr inbounds [2 x ptr], ptr %.offload_ptrs, i32 0, i32 1
+!CHECK: store ptr getelementptr (i8, ptr @var_common_, i64 4), ptr %[[OFFLOAD_PTR_ARR_1]], align 8

diff  --git a/flang/test/Lower/OpenMP/common-block-map.f90 b/flang/test/Lower/OpenMP/common-block-map.f90
new file mode 100644
index 0000000000000..5033129683a8e
--- /dev/null
+++ b/flang/test/Lower/OpenMP/common-block-map.f90
@@ -0,0 +1,83 @@
+!RUN: %flang_fc1 -emit-hlfir -fopenmp %s -o - | FileCheck %s
+
+!CHECK: fir.global common @var_common_(dense<0> : vector<8xi8>) {{.*}} : !fir.array<8xi8>
+!CHECK: fir.global common @var_common_link_(dense<0> : vector<8xi8>) {{{.*}} omp.declare_target = #omp.declaretarget<device_type = (any), capture_clause = (link)>} : !fir.array<8xi8>
+
+!CHECK-LABEL: func.func @_QPmap_full_block
+!CHECK: %[[CB_ADDR:.*]] = fir.address_of(@var_common_) : !fir.ref<!fir.array<8xi8>>
+!CHECK: %[[MAP:.*]] = omp.map.info var_ptr(%[[CB_ADDR]] : !fir.ref<!fir.array<8xi8>>, !fir.array<8xi8>) map_clauses(tofrom) capture(ByRef) -> !fir.ref<!fir.array<8xi8>> {name = "var_common"}
+!CHECK: omp.target map_entries(%[[MAP]] -> %[[MAP_ARG:.*]] : !fir.ref<!fir.array<8xi8>>) {
+!CHECK:  ^bb0(%[[MAP_ARG]]: !fir.ref<!fir.array<8xi8>>):
+!CHECK:    %[[CONV:.*]] = fir.convert %[[MAP_ARG]] : (!fir.ref<!fir.array<8xi8>>) -> !fir.ref<!fir.array<?xi8>>
+!CHECK:    %[[INDEX:.*]] = arith.constant 0 : index
+!CHECK:    %[[COORD:.*]] = fir.coordinate_of %[[CONV]], %[[INDEX]] : (!fir.ref<!fir.array<?xi8>>, index) -> !fir.ref<i8>
+!CHECK:    %[[CONV2:.*]] = fir.convert %[[COORD]] : (!fir.ref<i8>) -> !fir.ref<i32>
+!CHECK:    %[[CB_MEMBER_1:.*]]:2 = hlfir.declare %[[CONV2]] {uniq_name = "_QFmap_full_blockEvar1"} : (!fir.ref<i32>) -> (!fir.ref<i32>, !fir.ref<i32>)
+!CHECK:    %[[CONV3:.*]] = fir.convert %[[MAP_ARG]] : (!fir.ref<!fir.array<8xi8>>) -> !fir.ref<!fir.array<?xi8>>
+!CHECK:    %[[INDEX2:.*]] = arith.constant 4 : index
+!CHECK:    %[[COORD2:.*]] = fir.coordinate_of %[[CONV3]], %[[INDEX2]] : (!fir.ref<!fir.array<?xi8>>, index) -> !fir.ref<i8>
+!CHECK:    %[[CONV4:.*]] = fir.convert %[[COORD2]] : (!fir.ref<i8>) -> !fir.ref<i32>
+!CHECK:    %[[CB_MEMBER_2:.*]]:2 = hlfir.declare %[[CONV4]] {uniq_name = "_QFmap_full_blockEvar2"} : (!fir.ref<i32>) -> (!fir.ref<i32>, !fir.ref<i32>)
+subroutine map_full_block
+    implicit none
+    common /var_common/ var1, var2
+    integer :: var1, var2
+!$omp target map(tofrom: /var_common/)
+    var1 = var1 + 20
+    var2 = var2 + 30
+!$omp end target
+end
+
+!CHECK-LABEL: @_QPmap_mix_of_members
+!CHECK: %[[COMMON_BLOCK:.*]] = fir.address_of(@var_common_) : !fir.ref<!fir.array<8xi8>>
+!CHECK: %[[CB_CONV:.*]] = fir.convert %[[COMMON_BLOCK]] : (!fir.ref<!fir.array<8xi8>>) -> !fir.ref<!fir.array<?xi8>>
+!CHECK: %[[INDEX:.*]] = arith.constant 0 : index
+!CHECK: %[[COORD:.*]] = fir.coordinate_of %[[CB_CONV]], %[[INDEX]] : (!fir.ref<!fir.array<?xi8>>, index) -> !fir.ref<i8>
+!CHECK: %[[CONV:.*]] = fir.convert %[[COORD]] : (!fir.ref<i8>) -> !fir.ref<i32>
+!CHECK: %[[CB_MEMBER_1:.*]]:2 = hlfir.declare %[[CONV]] {uniq_name = "_QFmap_mix_of_membersEvar1"} : (!fir.ref<i32>) -> (!fir.ref<i32>, !fir.ref<i32>)
+!CHECK: %[[CB_CONV:.*]] = fir.convert %[[COMMON_BLOCK]] : (!fir.ref<!fir.array<8xi8>>) -> !fir.ref<!fir.array<?xi8>>
+!CHECK: %[[INDEX:.*]] = arith.constant 4 : index
+!CHECK: %[[COORD:.*]] = fir.coordinate_of %[[CB_CONV]], %[[INDEX]] : (!fir.ref<!fir.array<?xi8>>, index) -> !fir.ref<i8>
+!CHECK: %[[CONV:.*]] = fir.convert %[[COORD]] : (!fir.ref<i8>) -> !fir.ref<i32>
+!CHECK: %[[CB_MEMBER_2:.*]]:2 = hlfir.declare %[[CONV]] {uniq_name = "_QFmap_mix_of_membersEvar2"} : (!fir.ref<i32>) -> (!fir.ref<i32>, !fir.ref<i32>)
+!CHECK: %[[MAP_EXP:.*]] = omp.map.info var_ptr(%[[CB_MEMBER_2]]#0 : !fir.ref<i32>, i32) map_clauses(tofrom) capture(ByRef) -> !fir.ref<i32> {name = "var2"}
+!CHECK: %[[MAP_IMP:.*]] = omp.map.info var_ptr(%[[CB_MEMBER_1]]#1 : !fir.ref<i32>, i32) map_clauses(implicit, exit_release_or_enter_alloc) capture(ByCopy) -> !fir.ref<i32> {name = "var1"}
+!CHECK: omp.target map_entries(%[[MAP_EXP]] -> %[[ARG_EXP:.*]], %[[MAP_IMP]] -> %[[ARG_IMP:.*]] : !fir.ref<i32>, !fir.ref<i32>) {
+!CHECK: ^bb0(%[[ARG_EXP]]: !fir.ref<i32>, %[[ARG_IMP]]: !fir.ref<i32>):
+!CHECK:  %[[EXP_MEMBER:.*]]:2 = hlfir.declare %[[ARG_EXP]] {uniq_name = "_QFmap_mix_of_membersEvar2"} : (!fir.ref<i32>) -> (!fir.ref<i32>, !fir.ref<i32>)
+!CHECK:  %[[IMP_MEMBER:.*]]:2 = hlfir.declare %[[ARG_IMP]] {uniq_name = "_QFmap_mix_of_membersEvar1"} : (!fir.ref<i32>) -> (!fir.ref<i32>, !fir.ref<i32>)
+subroutine map_mix_of_members
+    implicit none
+    common /var_common/ var1, var2
+    integer :: var1, var2
+
+!$omp target map(tofrom: var2)
+  var2 = var1
+!$omp end target
+end
+
+!CHECK-LABEL: @_QQmain
+!CHECK: %[[DECL_TAR_CB:.*]] = fir.address_of(@var_common_link_) : !fir.ref<!fir.array<8xi8>>
+!CHECK: %[[MAP_DECL_TAR_CB:.*]] = omp.map.info var_ptr(%[[DECL_TAR_CB]] : !fir.ref<!fir.array<8xi8>>, !fir.array<8xi8>) map_clauses(tofrom) capture(ByRef) -> !fir.ref<!fir.array<8xi8>> {name = "var_common_link"}
+!CHECK: omp.target map_entries(%[[MAP_DECL_TAR_CB]] -> %[[MAP_DECL_TAR_ARG:.*]] : !fir.ref<!fir.array<8xi8>>) {
+!CHECK: ^bb0(%[[MAP_DECL_TAR_ARG]]: !fir.ref<!fir.array<8xi8>>):
+!CHECK:  %[[CONV:.*]] = fir.convert %[[MAP_DECL_TAR_ARG]] : (!fir.ref<!fir.array<8xi8>>) -> !fir.ref<!fir.array<?xi8>>
+!CHECK:  %[[INDEX:.*]] = arith.constant 0 : index
+!CHECK:  %[[COORD:.*]] = fir.coordinate_of %[[CONV]], %[[INDEX]] : (!fir.ref<!fir.array<?xi8>>, index) -> !fir.ref<i8>
+!CHECK:  %[[CONV:.*]] = fir.convert %[[COORD]] : (!fir.ref<i8>) -> !fir.ref<i32>
+!CHECK:  %[[MEMBER_ONE:.*]]:2 = hlfir.declare %[[CONV]] {uniq_name = "_QFElink1"} : (!fir.ref<i32>) -> (!fir.ref<i32>, !fir.ref<i32>)
+!CHECK:  %[[CONV:.*]] = fir.convert %[[MAP_DECL_TAR_ARG]] : (!fir.ref<!fir.array<8xi8>>) -> !fir.ref<!fir.array<?xi8>>
+!CHECK:  %[[INDEX:.*]] = arith.constant 4 : index
+!CHECK:  %[[COORD:.*]] = fir.coordinate_of %[[CONV]], %[[INDEX]] : (!fir.ref<!fir.array<?xi8>>, index) -> !fir.ref<i8>
+!CHECK:  %[[CONV:.*]] = fir.convert %[[COORD]] : (!fir.ref<i8>) -> !fir.ref<i32>
+!CHECK:  %[[MEMBER_TWO:.*]]:2 = hlfir.declare %[[CONV]] {uniq_name = "_QFElink2"} : (!fir.ref<i32>) -> (!fir.ref<i32>, !fir.ref<i32>)
+program main
+    implicit none
+    common /var_common_link/ link1, link2
+    integer :: link1, link2
+    !$omp declare target link(/var_common_link/)
+
+!$omp target map(tofrom: /var_common_link/)
+    link1 = link2 + 20
+!$omp end target
+end program

diff  --git a/llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp b/llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp
index dbf7154229d38..65231f50566c3 100644
--- a/llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp
+++ b/llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp
@@ -5164,15 +5164,7 @@ static Function *createOutlinedFunction(
           ? make_range(Func->arg_begin() + 1, Func->arg_end())
           : Func->args();
 
-  // Rewrite uses of input valus to parameters.
-  for (auto InArg : zip(Inputs, ArgRange)) {
-    Value *Input = std::get<0>(InArg);
-    Argument &Arg = std::get<1>(InArg);
-    Value *InputCopy = nullptr;
-
-    Builder.restoreIP(
-        ArgAccessorFuncCB(Arg, Input, InputCopy, AllocaIP, Builder.saveIP()));
-
+  auto ReplaceValue = [](Value *Input, Value *InputCopy, Function *Func) {
     // Things like GEP's can come in the form of Constants. Constants and
     // ConstantExpr's do not have access to the knowledge of what they're
     // contained in, so we must dig a little to find an instruction so we
@@ -5198,8 +5190,49 @@ static Function *createOutlinedFunction(
       if (auto *Instr = dyn_cast<Instruction>(User))
         if (Instr->getFunction() == Func)
           Instr->replaceUsesOfWith(Input, InputCopy);
+  };
+
+  SmallVector<std::pair<Value *, Value *>> DeferredReplacement;
+
+  // Rewrite uses of input valus to parameters.
+  for (auto InArg : zip(Inputs, ArgRange)) {
+    Value *Input = std::get<0>(InArg);
+    Argument &Arg = std::get<1>(InArg);
+    Value *InputCopy = nullptr;
+
+    Builder.restoreIP(
+        ArgAccessorFuncCB(Arg, Input, InputCopy, AllocaIP, Builder.saveIP()));
+
+    // In certain cases a Global may be set up for replacement, however, this
+    // Global may be used in multiple arguments to the kernel, just segmented
+    // apart, for example, if we have a global array, that is sectioned into
+    // multiple mappings (technically not legal in OpenMP, but there is a case
+    // in Fortran for Common Blocks where this is neccesary), we will end up
+    // with GEP's into this array inside the kernel, that refer to the Global
+    // but are technically seperate arguments to the kernel for all intents and
+    // purposes. If we have mapped a segment that requires a GEP into the 0-th
+    // index, it will fold into an referal to the Global, if we then encounter
+    // this folded GEP during replacement all of the references to the
+    // Global in the kernel will be replaced with the argument we have generated
+    // that corresponds to it, including any other GEP's that refer to the
+    // Global that may be other arguments. This will invalidate all of the other
+    // preceding mapped arguments that refer to the same global that may be
+    // seperate segments. To prevent this, we defer global processing until all
+    // other processing has been performed.
+    if (llvm::isa<llvm::GlobalValue>(std::get<0>(InArg)) ||
+        llvm::isa<llvm::GlobalObject>(std::get<0>(InArg)) ||
+        llvm::isa<llvm::GlobalVariable>(std::get<0>(InArg))) {
+      DeferredReplacement.push_back(std::make_pair(Input, InputCopy));
+      continue;
+    }
+
+    ReplaceValue(Input, InputCopy, Func);
   }
 
+  // Replace all of our deferred Input values, currently just Globals.
+  for (auto Deferred : DeferredReplacement)
+    ReplaceValue(std::get<0>(Deferred), std::get<1>(Deferred), Func);
+
   // Restore insert point.
   Builder.restoreIP(OldInsertPoint);
 

diff  --git a/mlir/lib/Target/LLVMIR/Dialect/OpenMP/OpenMPToLLVMIRTranslation.cpp b/mlir/lib/Target/LLVMIR/Dialect/OpenMP/OpenMPToLLVMIRTranslation.cpp
index 35d992e574535..8832828a49e57 100644
--- a/mlir/lib/Target/LLVMIR/Dialect/OpenMP/OpenMPToLLVMIRTranslation.cpp
+++ b/mlir/lib/Target/LLVMIR/Dialect/OpenMP/OpenMPToLLVMIRTranslation.cpp
@@ -30,6 +30,7 @@
 #include "llvm/Frontend/OpenMP/OMPIRBuilder.h"
 #include "llvm/IR/DebugInfoMetadata.h"
 #include "llvm/IR/IRBuilder.h"
+#include "llvm/IR/ReplaceConstant.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/TargetParser/Triple.h"
 #include "llvm/Transforms/Utils/ModuleUtils.h"
@@ -1976,12 +1977,6 @@ llvm::Value *getSizeInBytes(DataLayout &dl, const mlir::Type &type,
                             Operation *clauseOp, llvm::Value *basePointer,
                             llvm::Type *baseType, llvm::IRBuilderBase &builder,
                             LLVM::ModuleTranslation &moduleTranslation) {
-  // utilising getTypeSizeInBits instead of getTypeSize as getTypeSize gives
-  // the size in inconsistent byte or bit format.
-  uint64_t underlyingTypeSzInBits = dl.getTypeSizeInBits(type);
-  if (auto arrTy = llvm::dyn_cast_if_present<LLVM::LLVMArrayType>(type))
-    underlyingTypeSzInBits = getArrayElementSizeInBits(arrTy, dl);
-
   if (auto memberClause =
           mlir::dyn_cast_if_present<mlir::omp::MapInfoOp>(clauseOp)) {
     // This calculates the size to transfer based on bounds and the underlying
@@ -2007,6 +2002,12 @@ llvm::Value *getSizeInBytes(DataLayout &dl, const mlir::Type &type,
         }
       }
 
+      // utilising getTypeSizeInBits instead of getTypeSize as getTypeSize gives
+      // the size in inconsistent byte or bit format.
+      uint64_t underlyingTypeSzInBits = dl.getTypeSizeInBits(type);
+      if (auto arrTy = llvm::dyn_cast_if_present<LLVM::LLVMArrayType>(type))
+        underlyingTypeSzInBits = getArrayElementSizeInBits(arrTy, dl);
+
       // The size in bytes x number of elements, the sizeInBytes stored is
       // the underyling types size, e.g. if ptr<i32>, it'll be the i32's
       // size, so we do some on the fly runtime math to get the size in
@@ -2017,7 +2018,7 @@ llvm::Value *getSizeInBytes(DataLayout &dl, const mlir::Type &type,
     }
   }
 
-  return builder.getInt64(underlyingTypeSzInBits / 8);
+  return builder.getInt64(dl.getTypeSizeInBits(type) / 8);
 }
 
 void collectMapDataFromMapOperands(MapInfoData &mapData,
@@ -2898,7 +2899,7 @@ static bool targetOpSupported(Operation &opInst) {
 static void
 handleDeclareTargetMapVar(MapInfoData &mapData,
                           LLVM::ModuleTranslation &moduleTranslation,
-                          llvm::IRBuilderBase &builder) {
+                          llvm::IRBuilderBase &builder, llvm::Function *func) {
   for (size_t i = 0; i < mapData.MapClause.size(); ++i) {
     // In the case of declare target mapped variables, the basePointer is
     // the reference pointer generated by the convertDeclareTargetAttr
@@ -2913,19 +2914,31 @@ handleDeclareTargetMapVar(MapInfoData &mapData,
     // reference pointer and the pointer are assigned in the kernel argument
     // structure for the host.
     if (mapData.IsDeclareTarget[i]) {
+      // If the original map value is a constant, then we have to make sure all
+      // of it's uses within the current kernel/function that we are going to
+      // rewrite are converted to instructions, as we will be altering the old
+      // use (OriginalValue) from a constant to an instruction, which will be
+      // illegal and ICE the compiler if the user is a constant expression of
+      // some kind e.g. a constant GEP.
+      if (auto *constant = dyn_cast<llvm::Constant>(mapData.OriginalValue[i]))
+        convertUsersOfConstantsToInstructions(constant, func, false);
+
       // The users iterator will get invalidated if we modify an element,
-      // so we populate this vector of uses to alter each user on an individual
-      // basis to emit its own load (rather than one load for all).
+      // so we populate this vector of uses to alter each user on an
+      // individual basis to emit its own load (rather than one load for
+      // all).
       llvm::SmallVector<llvm::User *> userVec;
       for (llvm::User *user : mapData.OriginalValue[i]->users())
         userVec.push_back(user);
 
       for (llvm::User *user : userVec) {
         if (auto *insn = dyn_cast<llvm::Instruction>(user)) {
-          auto *load = builder.CreateLoad(mapData.BasePointers[i]->getType(),
-                                          mapData.BasePointers[i]);
-          load->moveBefore(insn);
-          user->replaceUsesOfWith(mapData.OriginalValue[i], load);
+          if (insn->getFunction() == func) {
+            auto *load = builder.CreateLoad(mapData.BasePointers[i]->getType(),
+                                            mapData.BasePointers[i]);
+            load->moveBefore(insn);
+            user->replaceUsesOfWith(mapData.OriginalValue[i], load);
+          }
         }
       }
     }
@@ -3043,6 +3056,7 @@ convertOmpTarget(Operation &opInst, llvm::IRBuilderBase &builder,
   auto &targetRegion = targetOp.getRegion();
   DataLayout dl = DataLayout(opInst.getParentOfType<ModuleOp>());
   SmallVector<Value> mapOperands = targetOp.getMapOperands();
+  llvm::Function *llvmOutlinedFn = nullptr;
 
   LogicalResult bodyGenStatus = success();
   using InsertPointTy = llvm::OpenMPIRBuilder::InsertPointTy;
@@ -3052,7 +3066,7 @@ convertOmpTarget(Operation &opInst, llvm::IRBuilderBase &builder,
     // original function to the new outlined function.
     llvm::Function *llvmParentFn =
         moduleTranslation.lookupFunction(parentFn.getName());
-    llvm::Function *llvmOutlinedFn = codeGenIP.getBlock()->getParent();
+    llvmOutlinedFn = codeGenIP.getBlock()->getParent();
     assert(llvmParentFn && llvmOutlinedFn &&
            "Both parent and outlined functions must exist at this point");
 
@@ -3147,7 +3161,8 @@ convertOmpTarget(Operation &opInst, llvm::IRBuilderBase &builder,
   // Remap access operations to declare target reference pointers for the
   // device, essentially generating extra loadop's as necessary
   if (moduleTranslation.getOpenMPBuilder()->Config.isTargetDevice())
-    handleDeclareTargetMapVar(mapData, moduleTranslation, builder);
+    handleDeclareTargetMapVar(mapData, moduleTranslation, builder,
+                              llvmOutlinedFn);
 
   return bodyGenStatus;
 }

diff  --git a/mlir/test/Target/LLVMIR/omptarget-fortran-common-block-host.mlir b/mlir/test/Target/LLVMIR/omptarget-fortran-common-block-host.mlir
new file mode 100644
index 0000000000000..7273f53d0a3db
--- /dev/null
+++ b/mlir/test/Target/LLVMIR/omptarget-fortran-common-block-host.mlir
@@ -0,0 +1,59 @@
+// RUN: mlir-translate -mlir-to-llvmir %s | FileCheck %s
+
+// This test checks the offload sizes, map types and base pointers and pointers
+// provided to the OpenMP kernel argument structure are correct when lowering
+// to LLVM-IR from MLIR when a fortran common block is lowered alongside
+// the omp.map.info.
+
+module attributes {omp.is_target_device = false} {
+  llvm.func @omp_map_common_block_using_common_block_members() {
+    %0 = llvm.mlir.constant(4 : index) : i64
+    %1 = llvm.mlir.constant(0 : index) : i64
+    %2 = llvm.mlir.addressof @var_common_ : !llvm.ptr
+    %3 = llvm.getelementptr %2[%1] : (!llvm.ptr, i64) -> !llvm.ptr, i8
+    %4 = llvm.getelementptr %2[%0] : (!llvm.ptr, i64) -> !llvm.ptr, i8
+    %5 = omp.map.info var_ptr(%3 : !llvm.ptr, i32) map_clauses(tofrom) capture(ByRef) -> !llvm.ptr {name = "var1"}
+    %6 = omp.map.info var_ptr(%4 : !llvm.ptr, i32) map_clauses(tofrom) capture(ByRef) -> !llvm.ptr {name = "var2"}
+    omp.target map_entries(%5 -> %arg0, %6 -> %arg1 : !llvm.ptr, !llvm.ptr) {
+    ^bb0(%arg0: !llvm.ptr, %arg1: !llvm.ptr):
+      omp.terminator
+    }
+    llvm.return
+  }
+
+  llvm.func @omp_map_common_block_using_common_block_symbol() {
+    %0 = llvm.mlir.addressof @var_common_ : !llvm.ptr
+    %1 = omp.map.info var_ptr(%0 : !llvm.ptr, !llvm.array<8 x i8>) map_clauses(tofrom) capture(ByRef) -> !llvm.ptr {name = "var_common"}
+    omp.target map_entries(%1 -> %arg0 : !llvm.ptr) {
+    ^bb0(%arg0: !llvm.ptr):
+      omp.terminator
+    }
+    llvm.return
+  }
+
+  llvm.mlir.global common @var_common_(dense<0> : vector<8xi8>) {addr_space = 0 : i32, alignment = 4 : i64} : !llvm.array<8 x i8>
+}
+
+// CHECK: @[[GLOBAL_BYTE_ARRAY:.*]] = common global [8 x i8] zeroinitializer, align 4
+
+// CHECK: @.offload_sizes{{.*}} = private unnamed_addr constant [2 x i64] [i64 4, i64 4]
+// CHECK: @.offload_maptypes{{.*}} = private unnamed_addr constant [2 x i64] [i64 35, i64 35]
+
+// CHECK: @.offload_sizes{{.*}} = private unnamed_addr constant [1 x i64] [i64 8]
+// CHECK: @.offload_maptypes{{.*}} = private unnamed_addr constant [1 x i64] [i64 35]
+
+// CHECK: define void @omp_map_common_block_using_common_block_members()
+// CHECK:  %[[BASEPTRS:.*]] = getelementptr inbounds [2 x ptr], ptr %.offload_baseptrs, i32 0, i32 0
+// CHECK:  store ptr @[[GLOBAL_BYTE_ARRAY]], ptr %[[BASEPTRS]], align 8
+// CHECK:  %[[OFFLOADPTRS:.*]] = getelementptr inbounds [2 x ptr], ptr %.offload_ptrs, i32 0, i32 0
+// CHECK:  store ptr @[[GLOBAL_BYTE_ARRAY]], ptr %[[OFFLOADPTRS]], align 8
+// CHECK: %[[BASEPTRS:.*]] = getelementptr inbounds [2 x ptr], ptr %.offload_baseptrs, i32 0, i32 1
+// CHECK: store ptr getelementptr (i8, ptr @[[GLOBAL_BYTE_ARRAY]], i64 4), ptr %[[BASEPTRS]], align 8
+// CHECK: %[[OFFLOADPTRS:.*]] = getelementptr inbounds [2 x ptr], ptr %.offload_ptrs, i32 0, i32 1
+// CHECK: store ptr getelementptr (i8, ptr @[[GLOBAL_BYTE_ARRAY]], i64 4), ptr %[[OFFLOADPTRS]], align 8
+
+// CHECK: define void @omp_map_common_block_using_common_block_symbol()
+// CHECK:  %[[BASEPTRS:.*]] = getelementptr inbounds [1 x ptr], ptr %.offload_baseptrs, i32 0, i32 0
+// CHECK:  store ptr @[[GLOBAL_BYTE_ARRAY]], ptr %[[BASEPTRS]], align 8
+// CHECK:  %[[OFFLOADPTRS:.*]] = getelementptr inbounds [1 x ptr], ptr %.offload_ptrs, i32 0, i32 0
+// CHECK:  store ptr @[[GLOBAL_BYTE_ARRAY]], ptr %[[OFFLOADPTRS]], align 8
\ No newline at end of file

diff  --git a/offload/test/offloading/fortran/target-map-all-common-block-members.f90 b/offload/test/offloading/fortran/target-map-all-common-block-members.f90
new file mode 100644
index 0000000000000..def1e7c663073
--- /dev/null
+++ b/offload/test/offloading/fortran/target-map-all-common-block-members.f90
@@ -0,0 +1,55 @@
+! Offloading test checking interaction of
+! mapping all the members of a common block
+! to a target region
+! REQUIRES: flang, amdgcn-amd-amdhsa
+! UNSUPPORTED: nvptx64-nvidia-cuda
+! UNSUPPORTED: nvptx64-nvidia-cuda-LTO
+! UNSUPPORTED: aarch64-unknown-linux-gnu
+! UNSUPPORTED: aarch64-unknown-linux-gnu-LTO
+! UNSUPPORTED: x86_64-pc-linux-gnu
+! UNSUPPORTED: x86_64-pc-linux-gnu-LTO
+
+! RUN: %libomptarget-compile-fortran-run-and-check-generic
+program main
+    implicit none
+    common /var_common/ var1, var2, var3
+    integer :: var1, var2, var3
+
+    call modify_1
+
+  !$omp target map(tofrom: var1, var2, var3)
+    var3 = var3 * 10
+    var2 = var2 * 10
+    var1 = var1 * 10
+  !$omp end target
+
+  call modify_2
+
+  print *, var1
+  print *, var2
+  print *, var3
+end program
+
+subroutine modify_1
+  common /var_common/ var1, var2, var3
+  integer :: var1, var2, var3
+!$omp target map(tofrom: var2, var1, var3)
+  var3 = var3 + 40
+  var2 = var2 + 20
+  var1 = var1 + 30
+!$omp end target
+end
+
+subroutine modify_2
+  common /var_common/ var1, var2, var3
+  integer :: var1, var2, var3
+!$omp target map(tofrom: var2, var3, var1)
+  var3 = var3 + 20
+  var1 = var1 + 10
+  var2 = var2 + 15
+!$omp end target
+end
+
+!CHECK: 310
+!CHECK: 215
+!CHECK: 420

diff  --git a/offload/test/offloading/fortran/target-map-common-block.f90 b/offload/test/offloading/fortran/target-map-common-block.f90
new file mode 100644
index 0000000000000..8fcd504950515
--- /dev/null
+++ b/offload/test/offloading/fortran/target-map-common-block.f90
@@ -0,0 +1,50 @@
+! Offloading test checking interaction of
+! mapping a full common block in a target
+! region
+! REQUIRES: flang, amdgcn-amd-amdhsa
+! UNSUPPORTED: nvptx64-nvidia-cuda
+! UNSUPPORTED: nvptx64-nvidia-cuda-LTO
+! UNSUPPORTED: aarch64-unknown-linux-gnu
+! UNSUPPORTED: aarch64-unknown-linux-gnu-LTO
+! UNSUPPORTED: x86_64-pc-linux-gnu
+! UNSUPPORTED: x86_64-pc-linux-gnu-LTO
+
+! RUN: %libomptarget-compile-fortran-run-and-check-generic
+program main
+    implicit none
+    common /var_common/ var1, var2
+    integer :: var1, var2
+
+    call modify_1
+
+  !$omp target map(tofrom: /var_common/)
+      var1 = var1 + 20
+      var2 = var2 + 50
+  !$omp end target
+
+    call modify_2
+
+    print *, var1
+    print *, var2
+end program
+
+subroutine modify_1
+  common /var_common/ var1, var2
+  integer :: var1, var2
+!$omp target map(tofrom: /var_common/)
+  var1 = var1 + 20
+  var2 = var2 + 30
+!$omp end target
+end
+
+subroutine modify_2
+  common /var_common/ var1, var2
+  integer :: var1, var2
+!$omp target map(tofrom: /var_common/)
+  var1 = var1 * 10
+  var2 = var2 * 10
+!$omp end target
+end
+
+!CHECK: 400
+!CHECK: 800

diff  --git a/offload/test/offloading/fortran/target-map-declare-target-link-common-block.f90 b/offload/test/offloading/fortran/target-map-declare-target-link-common-block.f90
new file mode 100644
index 0000000000000..47f50840befd3
--- /dev/null
+++ b/offload/test/offloading/fortran/target-map-declare-target-link-common-block.f90
@@ -0,0 +1,72 @@
+! Offloading test checking interaction of
+! mapping a declare target link common
+! block with device_type any to a target
+! region
+! REQUIRES: flang, amdgcn-amd-amdhsa
+! UNSUPPORTED: nvptx64-nvidia-cuda
+! UNSUPPORTED: nvptx64-nvidia-cuda-LTO
+! UNSUPPORTED: aarch64-unknown-linux-gnu
+! UNSUPPORTED: aarch64-unknown-linux-gnu-LTO
+! UNSUPPORTED: x86_64-pc-linux-gnu
+! UNSUPPORTED: x86_64-pc-linux-gnu-LTO
+
+! RUN: %libomptarget-compile-fortran-run-and-check-generic
+program main
+    implicit none
+    common /var_common/ var1, var2, var3
+    integer :: var1, var2, var3
+    !$omp declare target link(/var_common/)
+
+    call modify_1
+
+  !$omp target map(tofrom: var2)
+    var2 = var2 + var3
+  !$omp end target
+
+  call modify_2
+  call modify_3
+
+  print *, var1
+  print *, var2
+  print *, var3
+end program
+
+subroutine modify_1
+  common /var_common/ var1, var2, var3
+  integer :: var1, var2, var3
+
+!$omp target map(tofrom: /var_common/)
+  var1 = 10
+  var2 = 20
+  var3 = 30
+!$omp end target
+
+end
+
+subroutine modify_2
+  common /var_common/ var1, var2, var3
+  integer :: var1, var2, var3
+  integer :: copy
+
+!$omp target map(tofrom: copy)
+  copy =  var2 + var3
+!$omp end target
+
+  print *, copy
+end
+
+subroutine modify_3
+  common /var_common/ var1, var2, var3
+  integer :: var1, var2, var3
+
+!$omp target map(tofrom: /var_common/)
+  var1 = var1 + var1
+  var2 = var2 + var2
+  var3 = var3 + var3
+!$omp end target
+end
+
+!CHECK: 80
+!CHECK: 20
+!CHECK: 100
+!CHECK: 60
\ No newline at end of file

diff  --git a/offload/test/offloading/fortran/target-map-first-common-block-member.f90 b/offload/test/offloading/fortran/target-map-first-common-block-member.f90
new file mode 100644
index 0000000000000..69c1fa13501d2
--- /dev/null
+++ b/offload/test/offloading/fortran/target-map-first-common-block-member.f90
@@ -0,0 +1,47 @@
+! Offloading test checking interaction of
+! mapping a member of a common block to a
+! target region
+! REQUIRES: flang, amdgcn-amd-amdhsa
+! UNSUPPORTED: nvptx64-nvidia-cuda
+! UNSUPPORTED: nvptx64-nvidia-cuda-LTO
+! UNSUPPORTED: aarch64-unknown-linux-gnu
+! UNSUPPORTED: aarch64-unknown-linux-gnu-LTO
+! UNSUPPORTED: x86_64-pc-linux-gnu
+! UNSUPPORTED: x86_64-pc-linux-gnu-LTO
+
+! RUN: %libomptarget-compile-fortran-run-and-check-generic
+program main
+    implicit none
+    common /var_common/ var1, var2
+    integer :: var1, var2
+
+    call modify_1
+
+  !$omp target map(tofrom: var1)
+      var1 = var1 + 20
+  !$omp end target
+
+    call modify_2
+
+      print *, var1
+      print *, var2
+end program
+
+subroutine modify_1
+  common /var_common/ var1, var2
+  integer :: var1, var2
+!$omp target map(tofrom: var1)
+  var1 = var1 + 20
+!$omp end target
+end
+
+subroutine modify_2
+  common /var_common/ var1, var2
+  integer :: var1, var2
+!$omp target map(tofrom: var1)
+  var1 = var1 * 10
+!$omp end target
+end
+
+!CHECK: 400
+!CHECK: 0
\ No newline at end of file

diff  --git a/offload/test/offloading/fortran/target-map-mix-imp-exp-common-block-members.f90 b/offload/test/offloading/fortran/target-map-mix-imp-exp-common-block-members.f90
new file mode 100644
index 0000000000000..672630aec7d7c
--- /dev/null
+++ b/offload/test/offloading/fortran/target-map-mix-imp-exp-common-block-members.f90
@@ -0,0 +1,58 @@
+! Offloading test checking interaction of
+! mapping all the members of a common block
+! with a mix of explicit and implicit
+! mapping to a target region
+! REQUIRES: flang, amdgcn-amd-amdhsa
+! UNSUPPORTED: nvptx64-nvidia-cuda
+! UNSUPPORTED: nvptx64-nvidia-cuda-LTO
+! UNSUPPORTED: aarch64-unknown-linux-gnu
+! UNSUPPORTED: aarch64-unknown-linux-gnu-LTO
+! UNSUPPORTED: x86_64-pc-linux-gnu
+! UNSUPPORTED: x86_64-pc-linux-gnu-LTO
+
+! RUN: %libomptarget-compile-fortran-run-and-check-generic
+program main
+    implicit none
+    common /var_common/ var1, var2, var3
+    integer :: var1, var2, var3
+
+    call modify_1
+
+    !$omp target map(tofrom: var2)
+      var2 = var2 + var3
+    !$omp end target
+
+    call modify_2
+
+    print *, var1
+    print *, var2
+    print *, var3
+end program
+
+subroutine modify_1
+    common /var_common/ var1, var2, var3
+    integer :: var1, var2, var3
+
+  !$omp target map(tofrom: /var_common/)
+    var1 = 10
+    var2 = 20
+    var3 = 30
+  !$omp end target
+end
+
+subroutine modify_2
+    common /var_common/ var1, var2, var3
+    integer :: var1, var2, var3
+    integer :: copy
+
+  !$omp target map(tofrom: copy)
+    copy =  var2 + var3
+  !$omp end target
+
+    print *, copy
+end
+
+!CHECK: 80
+!CHECK: 10
+!CHECK: 50
+!CHECK: 30

diff  --git a/offload/test/offloading/fortran/target-map-second-common-block-member.f90 b/offload/test/offloading/fortran/target-map-second-common-block-member.f90
new file mode 100644
index 0000000000000..3aa937eb9adc6
--- /dev/null
+++ b/offload/test/offloading/fortran/target-map-second-common-block-member.f90
@@ -0,0 +1,47 @@
+! Offloading test checking interaction of
+! mapping a member of a common block to a
+! target region
+! REQUIRES: flang, amdgcn-amd-amdhsa
+! UNSUPPORTED: nvptx64-nvidia-cuda
+! UNSUPPORTED: nvptx64-nvidia-cuda-LTO
+! UNSUPPORTED: aarch64-unknown-linux-gnu
+! UNSUPPORTED: aarch64-unknown-linux-gnu-LTO
+! UNSUPPORTED: x86_64-pc-linux-gnu
+! UNSUPPORTED: x86_64-pc-linux-gnu-LTO
+
+! RUN: %libomptarget-compile-fortran-run-and-check-generic
+program main
+    implicit none
+    common /var_common/ var1, var2
+    integer :: var1, var2
+
+    call modify_1
+
+  !$omp target map(tofrom: var2)
+      var2 = var2 + 20
+  !$omp end target
+
+    call modify_2
+
+      print *, var1
+      print *, var2
+end program
+
+subroutine modify_1
+  common /var_common/ var1, var2
+  integer :: var1, var2
+!$omp target map(tofrom: var2)
+  var2 = var2 + 20
+!$omp end target
+end
+
+subroutine modify_2
+  common /var_common/ var1, var2
+  integer :: var1, var2
+!$omp target map(tofrom: var2)
+  var2 = var2 * 10
+!$omp end target
+end
+
+!CHECK: 0
+!CHECK: 400