[flang] Lower parentheses with hlfir.as_expr and hlfir.no_reassoc

[jeanPerier]

Summary

Depends on D139520

[clementval]

LGTM

flang/lib/Lower/ConvertExprToHLFIR.cpp

mlir::Value res = fir::factory::Complex{builder, loc}.extractComplexPart(
         lhs, op.isImaginaryPart);
     return hlfir::EntityWithAttributes{res};
   }
 };
 
 template <typename T>
 struct UnaryOp<Fortran::evaluate::Parentheses<T>> {
   using Op = Fortran::evaluate::Parentheses<T>;
-  static hlfir::EntityWithAttributes
-  gen(mlir::Location loc, fir::FirOpBuilder &, const Op &, hlfir::Entity) {
-    TODO(loc, "Parentheses lowering to HLFIR");
+  static hlfir::EntityWithAttributes gen(mlir::Location loc,
+                                         fir::FirOpBuilder &builder,
+                                         const Op &op, hlfir::Entity lhs) {
+    if (lhs.isVariable())
+      return hlfir::EntityWithAttributes{
+          builder.create<hlfir::AsExprOp>(loc, lhs)};
+    return hlfir::EntityWithAttributes{
+        builder.create<hlfir::NoReassocOp>(loc, lhs.getType(), lhs)};
   }
 };
 
 template <Fortran::common::TypeCategory TC1, int KIND,
           Fortran::common::TypeCategory TC2>
 struct UnaryOp<
     Fortran::evaluate::Convert<Fortran::evaluate::Type<TC1, KIND>, TC2>> {
   using Op =

flang/lib/Optimizer/Builder/HLFIRTools.cpp

 }
 
 void hlfir::genLengthParameters(mlir::Location loc, fir::FirOpBuilder &builder,
                                 Entity entity,
                                 llvm::SmallVectorImpl<mlir::Value> &result) {
   if (!entity.hasLengthParameters())
     return;
   if (entity.getType().isa<hlfir::ExprType>()) {
+    mlir::Value expr = entity;
+    if (auto reassoc = expr.getDefiningOp<hlfir::NoReassocOp>())
+      expr = reassoc.getVal();
     // Going through fir::ExtendedValue would create a temp,
     // which is not desired for an inquiry.
     // TODO: make this an interface when adding further character producing ops.
-    if (auto concat = entity.getDefiningOp<hlfir::ConcatOp>()) {
+    if (auto concat = expr.getDefiningOp<hlfir::ConcatOp>()) {
       result.push_back(concat.getLength());
       return;
+    } else if (auto asExpr = expr.getDefiningOp<hlfir::AsExprOp>()) {
+      hlfir::genLengthParameters(loc, builder, hlfir::Entity{asExpr.getVar()},
+                                 result);
+      return;
     }
     TODO(loc, "inquire type parameters of hlfir.expr");
   }
 
   if (entity.isCharacter()) {
     auto [exv, cleanup] = translateToExtendedValue(loc, builder, entity);
     assert(!cleanup && "translation of entity should not yield cleanup");
     result.push_back(fir::factory::readCharLen(builder, loc, exv));

flang/test/Lower/HLFIR/unary-ops.f90

 ! Test lowering of unary intrinsic operations to HLFIR
 ! RUN: bbc -emit-fir -hlfir -o - %s 2>&1 | FileCheck %s
 
+subroutine parentheses_numeric_var(x)
+  integer :: x
+  call bar((x))
+end subroutine
+! CHECK-LABEL: func.func @_QPparentheses_numeric_var(
+! CHECK:  %[[VAL_2:.*]] = fir.load %{{.*}} : !fir.ref<i32>
+! CHECK:  %[[VAL_3:.*]] = hlfir.no_reassoc %[[VAL_2]] : i32
+
+subroutine parentheses_numeric_expr(x)
+  real :: x
+  call bar((x+1000.)*2.)
+end subroutine
+! CHECK-LABEL: func.func @_QPparentheses_numeric_expr(
+! CHECK:  %[[VAL_4:.*]] = arith.addf
+! CHECK:  %[[VAL_5:.*]] = hlfir.no_reassoc %[[VAL_4]] : f32
+! CHECK:  %[[VAL_7:.*]] = arith.mulf %[[VAL_5]], %{{.*}}
+
+subroutine parentheses_char_var(x)
+  character(*) :: x
+  call bar2((x))
+end subroutine
+! CHECK-LABEL: func.func @_QPparentheses_char_var(
+! CHECK:  %[[VAL_2:.*]]:2 = hlfir.declare
+! CHECK:  %[[VAL_3:.*]] = hlfir.as_expr %[[VAL_2]]#0 : (!fir.boxchar<1>) -> !hlfir.expr<!fir.char<1,?>>
+
+subroutine parentheses_char_expr(x)
+  character(*) :: x
+  call bar2((x//x)//x)
+end subroutine
+! CHECK-LABEL: func.func @_QPparentheses_char_expr(
+! CHECK:  %[[VAL_4:.*]] = hlfir.concat
+! CHECK:  %[[VAL_5:.*]] = hlfir.no_reassoc %[[VAL_4]] : !hlfir.expr<!fir.char<1,?>>
+! CHECK:  %[[VAL_7:.*]] = hlfir.concat %[[VAL_5]], %{{.*}} len %{{.*}}
 subroutine test_not(l, x)
   logical :: l, x
   l = .not.x
 end subroutine
 ! CHECK-LABEL: func.func @_QPtest_not(
 ! CHECK:  %[[VAL_3:.*]]:2 = hlfir.declare %{{.*}}x"} : (!fir.ref<!fir.logical<4>>) -> (!fir.ref<!fir.logical<4>>, !fir.ref<!fir.logical<4>>)
 ! CHECK:  %[[VAL_4:.*]] = fir.load %[[VAL_3]]#0 : !fir.ref<!fir.logical<4>>
 ! CHECK:  %[[VAL_5:.*]] = arith.constant true