[flang] Fixed fir.dummy_scope generation to work for TBAA.

flang/lib/Lower/Bridge.cpp

@@ -5508,7 +5508,10 @@ class FirConverter : public Fortran::lower::AbstractConverter {
     for (const Fortran::lower::CalleeInterface::PassedEntity &arg :
          callee.getPassedArguments())
       mapPassedEntity(arg);
-    if (lowerToHighLevelFIR() && !callee.getPassedArguments().empty()) {
+
+    // Always generate fir.dummy_scope even if there are no arguments.
+    // It is currently used to create proper TBAA forest.
+    if (lowerToHighLevelFIR()) {
       mlir::Value scopeOp = builder->create<fir::DummyScopeOp>(toLocation());
       setDummyArgsScope(scopeOp);
     }

flang/test/Driver/emit-mlir.f90

@@ -13,6 +13,7 @@
 ! CHECK-SAME: dlti.dl_spec =
 ! CHECK-SAME: llvm.data_layout =
 ! CHECK-LABEL: func @_QQmain() {
+! CHECK-NEXT:  fir.dummy_scope
 ! CHECK-NEXT:  return
 ! CHECK-NEXT: }
 ! CHECK-NEXT: func.func private @_FortranAProgramStart(i32, !llvm.ptr, !llvm.ptr, !llvm.ptr)

flang/test/Lower/HLFIR/calls-f77.f90

@@ -9,6 +9,7 @@ subroutine call_no_arg()
   call void()
 end subroutine
 ! CHECK-LABEL: func.func @_QPcall_no_arg() {
+! CHECK-NEXT:  fir.dummy_scope
 ! CHECK-NEXT:  fir.call @_QPvoid() fastmath<contract> : () -> ()
 ! CHECK-NEXT:  return
 

flang/test/Lower/HLFIR/dummy-scope.f90

@@ -0,0 +1,52 @@
+! RUN: bbc -emit-hlfir %s -o - | FileCheck %s
+
+! Test fir.dummy_scope assignment to argument x
+subroutine sub_arg(x)
+  integer :: x
+end subroutine sub_arg
+! CHECK-LABEL:   func.func @_QPsub_arg(
+! CHECK-SAME:                          %[[VAL_0:[0-9]+|[a-zA-Z$._-][a-zA-Z0-9$._-]*]]: !fir.ref<i32> {fir.bindc_name = "x"}) {
+! CHECK:           %[[VAL_1:.*]] = fir.dummy_scope : !fir.dscope
+! CHECK:           %[[VAL_2:.*]]:2 = hlfir.declare %[[VAL_0]] dummy_scope %[[VAL_1]] {uniq_name = "_QFsub_argEx"} : (!fir.ref<i32>, !fir.dscope) -> (!fir.ref<i32>, !fir.ref<i32>)
+! CHECK:           return
+! CHECK:         }
+
+! Test fir.dummy_scope is created even when there are no arguments.
+subroutine sub_noarg
+end subroutine sub_noarg
+! CHECK-LABEL:   func.func @_QPsub_noarg() {
+! CHECK:           %[[VAL_0:.*]] = fir.dummy_scope : !fir.dscope
+! CHECK:           return
+! CHECK:         }
+
+! Test fir.dummy_scope assignment to argument x
+function func_arg(x)
+  integer :: x, func_arg
+  func_arg = x
+end function func_arg
+! CHECK-LABEL:   func.func @_QPfunc_arg(
+! CHECK-SAME:                           %[[VAL_0:[0-9]+|[a-zA-Z$._-][a-zA-Z0-9$._-]*]]: !fir.ref<i32> {fir.bindc_name = "x"}) -> i32 {
+! CHECK:           %[[VAL_1:.*]] = fir.dummy_scope : !fir.dscope
+! CHECK:           %[[VAL_2:.*]] = fir.alloca i32 {bindc_name = "func_arg", uniq_name = "_QFfunc_argEfunc_arg"}
+! CHECK:           %[[VAL_3:.*]]:2 = hlfir.declare %[[VAL_2]] {uniq_name = "_QFfunc_argEfunc_arg"} : (!fir.ref<i32>) -> (!fir.ref<i32>, !fir.ref<i32>)
+! CHECK:           %[[VAL_4:.*]]:2 = hlfir.declare %[[VAL_0]] dummy_scope %[[VAL_1]] {uniq_name = "_QFfunc_argEx"} : (!fir.ref<i32>, !fir.dscope) -> (!fir.ref<i32>, !fir.ref<i32>)
+! CHECK:           %[[VAL_5:.*]] = fir.load %[[VAL_4]]#0 : !fir.ref<i32>
+! CHECK:           hlfir.assign %[[VAL_5]] to %[[VAL_3]]#0 : i32, !fir.ref<i32>
+! CHECK:           %[[VAL_6:.*]] = fir.load %[[VAL_3]]#0 : !fir.ref<i32>
+! CHECK:           return %[[VAL_6]] : i32
+! CHECK:         }
+
+! Test fir.dummy_scope is created even when there are no arguments.
+function func_noarg
+  integer :: func_noarg
+  func_noarg = 1
+end function func_noarg
+! CHECK-LABEL:   func.func @_QPfunc_noarg() -> i32 {
+! CHECK:           %[[VAL_0:.*]] = fir.dummy_scope : !fir.dscope
+! CHECK:           %[[VAL_1:.*]] = fir.alloca i32 {bindc_name = "func_noarg", uniq_name = "_QFfunc_noargEfunc_noarg"}
+! CHECK:           %[[VAL_2:.*]]:2 = hlfir.declare %[[VAL_1]] {uniq_name = "_QFfunc_noargEfunc_noarg"} : (!fir.ref<i32>) -> (!fir.ref<i32>, !fir.ref<i32>)
+! CHECK:           %[[VAL_3:.*]] = arith.constant 1 : i32
+! CHECK:           hlfir.assign %[[VAL_3]] to %[[VAL_2]]#0 : i32, !fir.ref<i32>
+! CHECK:           %[[VAL_4:.*]] = fir.load %[[VAL_2]]#0 : !fir.ref<i32>
+! CHECK:           return %[[VAL_4]] : i32
+! CHECK:         }

flang/test/Lower/OpenMP/real10.f90

@@ -2,7 +2,7 @@
 
 !RUN: %flang_fc1 -emit-hlfir -fopenmp -triple amdgcn -fopenmp -fopenmp-is-target-device -o - %s | FileCheck %s
 
-!CHECK: hlfir.declare %0 {uniq_name = "_QFEx"} : (!fir.ref<f80>) -> (!fir.ref<f80>, !fir.ref<f80>)
+!CHECK: hlfir.declare %{{.*}} {uniq_name = "_QFEx"} : (!fir.ref<f80>) -> (!fir.ref<f80>, !fir.ref<f80>)
 
 program p
   real(10) :: x

flang/test/Lower/main_location.f90

@@ -12,6 +12,7 @@
 end
 
 ! TEST1: func.func @_QQmain() {
+! TEST1-NEXT: fir.dummy_scope : !fir.dscope loc("{{.*}}test1.f90":1:1)
 ! TEST1-NEXT: return loc("{{.*}}test1.f90":3:1)
 ! TEST1-NEXT: } loc("{{.*}}test1.f90":1:1)
 
@@ -22,5 +23,6 @@
 end program
 
 ! TEST2: func.func @_QQmain() {
+! TEST2-NEXT: fir.dummy_scope : !fir.dscope loc("{{.*}}test2.f90":2:1)
 ! TEST2-NEXT: return loc("{{.*}}test2.f90":4:1)
 ! TEST2-NEXT: } loc("{{.*}}test2.f90":2:1)

flang/test/Transforms/tbaa-with-dummy-scope2.fir

@@ -0,0 +1,106 @@
+// RUN: fir-opt --fir-add-alias-tags --split-input-file %s | FileCheck %s
+
+// This test demonstrates the need for fir.dummy_scope even
+// when a function does not have dummy arguments.
+//
+// The original source is:
+// module m
+//   integer :: glob
+// end module m
+// subroutine test1
+//   use m
+//   call inner(glob)
+//   glob = 2
+// contains
+//   subroutine inner(x)
+//     integer :: x
+//     integer :: y
+//     y = 1
+//     x = y
+//   end subroutine inner
+// end subroutine test1
+//
+// 'inner' function is manually inlined in FIR.
+// When fir.dummy_scope is missing, TBAA tags for glob and x
+// are placed into the same TBAA root. Since glob is a global
+// and x is a dummy argument, TBAA ends up reporting no-alias
+// for them, which is incorrect.
+func.func @_QPtest1() attributes {noinline} {
+  %c1_i32 = arith.constant 1 : i32
+  %c2_i32 = arith.constant 2 : i32
+  %0 = fir.alloca i32 {bindc_name = "y", uniq_name = "_QFtest1FinnerEy"}
+  %1 = fir.address_of(@_QMmEglob) : !fir.ref<i32>
+  %2 = fir.declare %1 {uniq_name = "_QMmEglob"} : (!fir.ref<i32>) -> !fir.ref<i32>
+  %3 = fir.dummy_scope : !fir.dscope
+  %4 = fir.declare %2 dummy_scope %3 {uniq_name = "_QFtest1FinnerEx"} : (!fir.ref<i32>, !fir.dscope) -> !fir.ref<i32>
+  %5 = fir.declare %0 {uniq_name = "_QFtest1FinnerEy"} : (!fir.ref<i32>) -> !fir.ref<i32>
+  fir.store %c1_i32 to %5 : !fir.ref<i32>
+  %6 = fir.load %5 : !fir.ref<i32>
+  fir.store %6 to %4 : !fir.ref<i32>
+  fir.store %c2_i32 to %2 : !fir.ref<i32>
+  return
+}
+// CHECK: #[[$ATTR_0:.+]] = #llvm.tbaa_root<id = "Flang function root _QPtest1">
+// CHECK: #[[$ATTR_1:.+]] = #llvm.tbaa_type_desc<id = "any access", members = {<#[[$ATTR_0]], 0>}>
+// CHECK: #[[$ATTR_2:.+]] = #llvm.tbaa_type_desc<id = "any data access", members = {<#[[$ATTR_1]], 0>}>
+// CHECK: #[[$ATTR_3:.+]] = #llvm.tbaa_type_desc<id = "dummy arg data", members = {<#[[$ATTR_2]], 0>}>
+// CHECK: #[[$ATTR_4:.+]] = #llvm.tbaa_type_desc<id = "global data", members = {<#[[$ATTR_2]], 0>}>
+// CHECK: #[[$ATTR_5:.+]] = #llvm.tbaa_type_desc<id = "dummy arg data/_QFtest1FinnerEx", members = {<#[[$ATTR_3]], 0>}>
+// CHECK: #[[$ATTR_6:.+]] = #llvm.tbaa_type_desc<id = "global data/_QMmEglob", members = {<#[[$ATTR_4]], 0>}>
+// CHECK: #[[$ATTR_7:.+]] = #llvm.tbaa_tag<base_type = #[[$ATTR_5]], access_type = #[[$ATTR_5]], offset = 0>
+// CHECK: #[[$ATTR_8:.+]] = #llvm.tbaa_tag<base_type = #[[$ATTR_6]], access_type = #[[$ATTR_6]], offset = 0>
+// CHECK-LABEL:   func.func @_QPtest1() attributes {noinline} {
+// CHECK:           %[[VAL_2:.*]] = fir.alloca i32 {bindc_name = "y", uniq_name = "_QFtest1FinnerEy"}
+// CHECK:           %[[VAL_3:.*]] = fir.address_of(@_QMmEglob) : !fir.ref<i32>
+// CHECK:           %[[VAL_4:.*]] = fir.declare %[[VAL_3]] {uniq_name = "_QMmEglob"} : (!fir.ref<i32>) -> !fir.ref<i32>
+// CHECK:           %[[VAL_5:.*]] = fir.dummy_scope : !fir.dscope
+// CHECK:           %[[VAL_6:.*]] = fir.declare %[[VAL_4]] dummy_scope %[[VAL_5]] {uniq_name = "_QFtest1FinnerEx"} : (!fir.ref<i32>, !fir.dscope) -> !fir.ref<i32>
+// CHECK:           %[[VAL_7:.*]] = fir.declare %[[VAL_2]] {uniq_name = "_QFtest1FinnerEy"} : (!fir.ref<i32>) -> !fir.ref<i32>
+// CHECK:           fir.store %{{.*}} to %[[VAL_7]] : !fir.ref<i32>
+// CHECK:           %[[VAL_8:.*]] = fir.load %[[VAL_7]] : !fir.ref<i32>
+// CHECK:           fir.store %[[VAL_8]] to %[[VAL_6]] {tbaa = [#[[$ATTR_7]]]} : !fir.ref<i32>
+// CHECK:           fir.store %{{.*}} to %[[VAL_4]] {tbaa = [#[[$ATTR_8]]]} : !fir.ref<i32>
+
+// -----
+
+// This test has fir.dummy_scope in place, and TBAA is correct.
+func.func @_QPtest2() attributes {noinline} {
+  %c1_i32 = arith.constant 1 : i32
+  %c2_i32 = arith.constant 2 : i32
+  %0 = fir.alloca i32 {bindc_name = "y", uniq_name = "_QFtest2FinnerEy"}
+  %test_dummy_scope = fir.dummy_scope : !fir.dscope
+  %1 = fir.address_of(@_QMmEglob) : !fir.ref<i32>
+  %2 = fir.declare %1 {uniq_name = "_QMmEglob"} : (!fir.ref<i32>) -> !fir.ref<i32>
+  %3 = fir.dummy_scope : !fir.dscope
+  %4 = fir.declare %2 dummy_scope %3 {uniq_name = "_QFtest2FinnerEx"} : (!fir.ref<i32>, !fir.dscope) -> !fir.ref<i32>
+  %5 = fir.declare %0 {uniq_name = "_QFtest2FinnerEy"} : (!fir.ref<i32>) -> !fir.ref<i32>
+  fir.store %c1_i32 to %5 : !fir.ref<i32>
+  %6 = fir.load %5 : !fir.ref<i32>
+  fir.store %6 to %4 : !fir.ref<i32>
+  fir.store %c2_i32 to %2 : !fir.ref<i32>
+  return
+}
+// CHECK: #[[$ATTR_0:.+]] = #llvm.tbaa_root<id = "Flang function root _QPtest2 - Scope 1">
+// CHECK: #[[$ATTR_1:.+]] = #llvm.tbaa_root<id = "Flang function root _QPtest2">
+// CHECK: #[[$ATTR_2:.+]] = #llvm.tbaa_type_desc<id = "any access", members = {<#[[$ATTR_0]], 0>}>
+// CHECK: #[[$ATTR_3:.+]] = #llvm.tbaa_type_desc<id = "any access", members = {<#[[$ATTR_1]], 0>}>
+// CHECK: #[[$ATTR_4:.+]] = #llvm.tbaa_type_desc<id = "any data access", members = {<#[[$ATTR_2]], 0>}>
+// CHECK: #[[$ATTR_5:.+]] = #llvm.tbaa_type_desc<id = "any data access", members = {<#[[$ATTR_3]], 0>}>
+// CHECK: #[[$ATTR_6:.+]] = #llvm.tbaa_type_desc<id = "dummy arg data", members = {<#[[$ATTR_4]], 0>}>
+// CHECK: #[[$ATTR_7:.+]] = #llvm.tbaa_type_desc<id = "global data", members = {<#[[$ATTR_5]], 0>}>
+// CHECK: #[[$ATTR_8:.+]] = #llvm.tbaa_type_desc<id = "dummy arg data/_QFtest2FinnerEx", members = {<#[[$ATTR_6]], 0>}>
+// CHECK: #[[$ATTR_9:.+]] = #llvm.tbaa_type_desc<id = "global data/_QMmEglob", members = {<#[[$ATTR_7]], 0>}>
+// CHECK: #[[$ATTR_10:.+]] = #llvm.tbaa_tag<base_type = #[[$ATTR_8]], access_type = #[[$ATTR_8]], offset = 0>
+// CHECK: #[[$ATTR_11:.+]] = #llvm.tbaa_tag<base_type = #[[$ATTR_9]], access_type = #[[$ATTR_9]], offset = 0>
+// CHECK-LABEL:   func.func @_QPtest2() attributes {noinline} {
+// CHECK:           %[[VAL_2:.*]] = fir.alloca i32 {bindc_name = "y", uniq_name = "_QFtest2FinnerEy"}
+// CHECK:           %[[VAL_3:.*]] = fir.dummy_scope : !fir.dscope
+// CHECK:           %[[VAL_4:.*]] = fir.address_of(@_QMmEglob) : !fir.ref<i32>
+// CHECK:           %[[VAL_5:.*]] = fir.declare %[[VAL_4]] {uniq_name = "_QMmEglob"} : (!fir.ref<i32>) -> !fir.ref<i32>
+// CHECK:           %[[VAL_6:.*]] = fir.dummy_scope : !fir.dscope
+// CHECK:           %[[VAL_7:.*]] = fir.declare %[[VAL_5]] dummy_scope %[[VAL_6]] {uniq_name = "_QFtest2FinnerEx"} : (!fir.ref<i32>, !fir.dscope) -> !fir.ref<i32>
+// CHECK:           %[[VAL_8:.*]] = fir.declare %[[VAL_2]] {uniq_name = "_QFtest2FinnerEy"} : (!fir.ref<i32>) -> !fir.ref<i32>
+// CHECK:           fir.store %{{.*}} to %[[VAL_8]] : !fir.ref<i32>
+// CHECK:           %[[VAL_9:.*]] = fir.load %[[VAL_8]] : !fir.ref<i32>
+// CHECK:           fir.store %[[VAL_9]] to %[[VAL_7]] {tbaa = [#[[$ATTR_10]]]} : !fir.ref<i32>
+// CHECK:           fir.store %{{.*}} to %[[VAL_5]] {tbaa = [#[[$ATTR_11]]]} : !fir.ref<i32>