[flang] Enable scalar real type in lowering

This patch enables scalar real type in lowering.
It is tested on function return types.

This patch is part of the upstreaming effort from fir-dev branch.

Depends on D119698

Reviewed By: kiranchandramohan

Differential Revision: https://reviews.llvm.org/D119699

Co-authored-by: Jean Perier <jperier@nvidia.com>

flang/lib/Lower/ConvertType.cpp

@@ -23,6 +23,27 @@
 // Intrinsic type translation helpers
 //===--------------------------------------------------------------------===//
 
+static mlir::Type genRealType(mlir::MLIRContext *context, int kind) {
+  if (Fortran::evaluate::IsValidKindOfIntrinsicType(
+          Fortran::common::TypeCategory::Real, kind)) {
+    switch (kind) {
+    case 2:
+      return mlir::FloatType::getF16(context);
+    case 3:
+      return mlir::FloatType::getBF16(context);
+    case 4:
+      return mlir::FloatType::getF32(context);
+    case 8:
+      return mlir::FloatType::getF64(context);
+    case 10:
+      return mlir::FloatType::getF80(context);
+    case 16:
+      return mlir::FloatType::getF128(context);
+    }
+  }
+  llvm_unreachable("REAL type translation not implemented");
+}
+
 template <int KIND>
 int getIntegerBits() {
   return Fortran::evaluate::Type<Fortran::common::TypeCategory::Integer,
@@ -58,7 +79,7 @@ static mlir::Type genFIRType(mlir::MLIRContext *context,
                              Fortran::common::TypeCategory tc, int kind) {
   switch (tc) {
   case Fortran::common::TypeCategory::Real:
-    TODO_NOLOC("genFIRType Real");
+    return genRealType(context, kind);
   case Fortran::common::TypeCategory::Integer:
     return genIntegerType(context, kind);
   case Fortran::common::TypeCategory::Complex:
@@ -107,66 +128,6 @@ mlir::Type genFIRType(mlir::MLIRContext *context) {
   }
 }
 
-template <>
-mlir::Type
-genFIRType<Fortran::common::TypeCategory::Real, 2>(mlir::MLIRContext *context) {
-  return mlir::FloatType::getF16(context);
-}
-
-template <>
-mlir::Type
-genFIRType<Fortran::common::TypeCategory::Real, 3>(mlir::MLIRContext *context) {
-  return mlir::FloatType::getBF16(context);
-}
-
-template <>
-mlir::Type
-genFIRType<Fortran::common::TypeCategory::Real, 4>(mlir::MLIRContext *context) {
-  return mlir::FloatType::getF32(context);
-}
-
-template <>
-mlir::Type
-genFIRType<Fortran::common::TypeCategory::Real, 8>(mlir::MLIRContext *context) {
-  return mlir::FloatType::getF64(context);
-}
-
-template <>
-mlir::Type genFIRType<Fortran::common::TypeCategory::Real, 10>(
-    mlir::MLIRContext *context) {
-  return fir::RealType::get(context, 10);
-}
-
-template <>
-mlir::Type genFIRType<Fortran::common::TypeCategory::Real, 16>(
-    mlir::MLIRContext *context) {
-  return fir::RealType::get(context, 16);
-}
-
-template <>
-mlir::Type
-genFIRType<Fortran::common::TypeCategory::Real>(mlir::MLIRContext *context,
-                                                int kind) {
-  if (Fortran::evaluate::IsValidKindOfIntrinsicType(
-          Fortran::common::TypeCategory::Real, kind)) {
-    switch (kind) {
-    case 2:
-      return genFIRType<Fortran::common::TypeCategory::Real, 2>(context);
-    case 3:
-      return genFIRType<Fortran::common::TypeCategory::Real, 3>(context);
-    case 4:
-      return genFIRType<Fortran::common::TypeCategory::Real, 4>(context);
-    case 8:
-      return genFIRType<Fortran::common::TypeCategory::Real, 8>(context);
-    case 10:
-      return genFIRType<Fortran::common::TypeCategory::Real, 10>(context);
-    case 16:
-      return genFIRType<Fortran::common::TypeCategory::Real, 16>(context);
-    }
-  }
-  llvm_unreachable("REAL type translation not implemented");
-}
-
 template <>
 mlir::Type
 genFIRType<Fortran::common::TypeCategory::Character>(mlir::MLIRContext *context,

flang/test/Lower/basic-function.f90

@@ -67,3 +67,34 @@ logical(8) function lfct4()
 end
 ! CHECK-LABEL: func @_QPlfct4() -> !fir.logical<8>
 ! CHECK:         return %{{.*}} : !fir.logical<8>
+
+real(2) function rfct1()
+end
+! CHECK-LABEL: func @_QPrfct1() -> f16
+! CHECK:         return %{{.*}} : f16
+
+real(3) function rfct2()
+end
+! CHECK-LABEL: func @_QPrfct2() -> bf16
+! CHECK:         return %{{.*}} : bf16
+
+real function rfct3()
+end
+! CHECK-LABEL: func @_QPrfct3() -> f32
+! CHECK:         return %{{.*}} : f32
+
+real(8) function rfct4()
+end
+! CHECK-LABEL: func @_QPrfct4() -> f64
+! CHECK:         return %{{.*}} : f64
+
+real(10) function rfct5()
+end
+! CHECK-LABEL: func @_QPrfct5() -> f80
+! CHECK:         return %{{.*}} : f80
+
+real(16) function rfct6()
+end
+! CHECK-LABEL: func @_QPrfct6() -> f128
+! CHECK:         return %{{.*}} : f128
+