[flang][openacc] Generate acc.bound op when local array is passed without subscript

[clementval]

Summary

Add support to generate the acc.bound operation when the array is passed without
any subscripts. Without this patch, no bound is generated.

[clementval]

Remove debug code

[clementval]

Some tests need an update.

[clementval]

Update older tests with correct bounds

[jeanPerier]

flang/lib/Lower/OpenACC.cpp

150–152

I do not follow why the extent is being substracted the lower bound here. Does the acc::DataBoundsOp extent depends on its startIdx argument?

BTW, is "zero" needed here (since it is an optional argument of acc::DataBoundsOp, isn't it implied to be zero when absent)?

[clementval]

flang/lib/Lower/OpenACC.cpp

150–152

That a mistake. Let me fix that.

If lbound is zero we can indeed omit it.

[clementval]

Fix extent and omit lowerbound

[clementval]

clang-format

[razvanlupusoru]

Thank you for normalizing the representation.

flang/lib/Lower/OpenACC.cpp

std::visit(
             },
             [&](const Fortran::parser::Name &name) {
               addOperands(*name.symbol);
             }},
         accObject.u);
   }
 }
 
+/// Generate the acc.bounds operation from the descriptor information.
 static llvm::SmallVector<mlir::Value>
 genBoundsOpsFromBox(fir::FirOpBuilder &builder, mlir::Location loc,
                     Fortran::lower::AbstractConverter &converter,
                     Fortran::lower::SymbolRef sym, mlir::Value box, int rank) {
   llvm::SmallVector<mlir::Value> bounds;
   mlir::Type idxTy = builder.getIndexType();
   fir::ExtendedValue dataExv = converter.getSymbolExtendedValue(sym);
   mlir::Type boundTy = builder.getType<mlir::acc::DataBoundsType>();
for (int dim = 0; dim < rank; ++dim) {
     mlir::Value bound = builder.create<mlir::acc::DataBoundsOp>(
         loc, boundTy, empty, empty, dimInfo.getExtent(),
         dimInfo.getByteStride(), true, baseLb);
     bounds.push_back(bound);
   }
   return bounds;
 }
 
+/// Generate acc.bounds operation for base array without any subscripts
+/// provided.
+static llvm::SmallVector<mlir::Value>
+genBaseBoundsOps(fir::FirOpBuilder &builder, mlir::Location loc,
+                 Fortran::lower::AbstractConverter &converter,
+                 const Fortran::parser::Name &name, mlir::Value baseAddr) {
+  mlir::Type idxTy = builder.getIndexType();
+  mlir::Type boundTy = builder.getType<mlir::acc::DataBoundsType>();
+  fir::ExtendedValue dataExv = converter.getSymbolExtendedValue(*name.symbol);
+  llvm::SmallVector<mlir::Value> bounds;
+
+  if (dataExv.rank() == 0)
+    return bounds;
+
+  for (std::size_t dim = 0; dim < dataExv.rank(); ++dim) {
+    mlir::Value zero = builder.createIntegerConstant(loc, idxTy, 0);
+    mlir::Value one = builder.createIntegerConstant(loc, idxTy, 1);
+    mlir::Value lbound =
+        fir::factory::readLowerBound(builder, loc, dataExv, dim, one);
+    mlir::Value extent = fir::factory::readExtent(builder, loc, dataExv, dim);
+    extent = builder.create<mlir::arith::SubIOp>(loc, extent, lbound);
+    mlir::Value bound = builder.create<mlir::acc::DataBoundsOp>(
+        loc, boundTy, zero, mlir::Value(), extent, one, false, lbound);
+    bounds.push_back(bound);
+  }
+  return bounds;
+}
+
+/// Generate acc.bounds operations for an array section when subscripts are
+/// provided.
 static llvm::SmallVector<mlir::Value>
 genBoundsOps(fir::FirOpBuilder &builder, mlir::Location loc,
              Fortran::lower::AbstractConverter &converter,
              Fortran::lower::StatementContext &stmtCtx,
              const std::list<Fortran::parser::SectionSubscript> &subscripts,
              std::stringstream &asFortran, const Fortran::parser::Name &name,
              mlir::Value baseAddr) {
   int dimension = 0;
std::visit(
                     mlir::Value baseAddr =
                         getDataOperandBaseAddr(*name.symbol, operandLocation);
                     llvm::SmallVector<mlir::Value> bounds;
                     if (fir::unwrapRefType(baseAddr.getType())
                             .isa<fir::BaseBoxType>())
                       bounds = genBoundsOpsFromBox(builder, operandLocation,
                                                    converter, *name.symbol,
                                                    baseAddr, (*expr).Rank());
+                    if (fir::unwrapRefType(baseAddr.getType())
+                            .isa<fir::SequenceType>())
+                      bounds = genBaseBoundsOps(builder, operandLocation,
+                                                converter, name, baseAddr);
                     createOpAndAddOperand(baseAddr, name.ToString(),
                                           operandLocation, bounds);
                   } else { // Unsupported
                     llvm::report_fatal_error(
                         "Unsupported type of OpenACC operand");
                   }
                 }
               }

flang/test/Lower/OpenACC/acc-enter-data.f90

 subroutine acc_enter_data_dummy(a, b, n, m)
   integer :: n, m
   real :: a(1:10)
   real :: b(n:m)
 
 !CHECK-LABEL: func.func @_QPacc_enter_data_dummy
 !CHECK-SAME:    %[[A:.*]]: !fir.ref<!fir.array<10xf32>> {fir.bindc_name = "a"}, %[[B:.*]]: !fir.ref<!fir.array<?xf32>> {fir.bindc_name = "b"}, %[[N:.*]]: !fir.ref<i32> {fir.bindc_name = "n"}, %[[M:.*]]: !fir.ref<i32> {fir.bindc_name = "m"}
 
+!CHECK: %[[C10:.*]] = arith.constant 10 : index
 !CHECK: %[[LOAD_N:.*]] = fir.load %[[N]] : !fir.ref<i32>
 !CHECK: %[[N_I64:.*]] = fir.convert %[[LOAD_N]] : (i32) -> i64
 !CHECK: %[[N_IDX:.*]] = fir.convert %[[N_I64]] : (i64) -> index
 !CHECK: %[[LOAD_M:.*]] = fir.load %[[M]] : !fir.ref<i32>
 !CHECK: %[[M_I64:.*]] = fir.convert %[[LOAD_M]] : (i32) -> i64
 !CHECK: %[[M_IDX:.*]] = fir.convert %[[M_I64]] : (i64) -> index
 !CHECK: %[[M_N:.*]] = arith.subi %[[M_IDX]], %[[N_IDX]] : index
 !CHECK: %[[C1:.*]] = arith.constant 1 : index
 !CHECK: %[[M_N_1:.*]] = arith.addi %[[M_N]], %[[C1]] : index
 !CHECK: %[[C0:.*]] = arith.constant 0 : index
 !CHECK: %[[CMP:.*]] = arith.cmpi sgt, %[[M_N_1]], %[[C0]] : index
 !CHECK: %[[EXT_B:.*]] = arith.select %[[CMP]], %[[M_N_1]], %[[C0]] : index
 
+  !$acc enter data create(a)
+!CHECK: %[[C0:.*]] = arith.constant 0 : index
+!CHECK: %[[C1:.*]] = arith.constant 1 : index
+!CHECK: %[[EXT:.*]] = arith.subi %[[C10]], %[[C1]] : index
+!CHECK: %[[BOUND:.*]] = acc.bounds lowerbound(%[[C0]] : index) extent(%[[EXT]] : index) stride(%[[C1]] : index) startIdx(%[[C1]] : index)
+!CHECK: %[[CREATE:.*]] = acc.create varPtr(%[[A]] : !fir.ref<!fir.array<10xf32>>) bounds(%[[BOUND]]) -> !fir.ref<!fir.array<10xf32>> {name = "a", structured = false}
+!CHECK: acc.enter_data dataOperands(%[[CREATE]] : !fir.ref<!fir.array<10xf32>>)
+
+  !$acc enter data create(b)
+!CHECK: %[[C0:.*]] = arith.constant 0 : index
+!CHECK: %[[C1:.*]] = arith.constant 1 : index
+!CHECK: %[[EXT:.*]] = arith.subi %[[EXT_B]], %[[N_IDX]] : index
+!CHECK: %[[BOUND:.*]] = acc.bounds lowerbound(%[[C0]] : index) extent(%[[EXT]] : index) stride(%[[C1]] : index) startIdx(%[[N_IDX]] : index)
+!CHECK: %[[CREATE:.*]] = acc.create varPtr(%[[B]] : !fir.ref<!fir.array<?xf32>>) bounds(%[[BOUND]]) -> !fir.ref<!fir.array<?xf32>> {name = "b", structured = false}
+!CHECK: acc.enter_data dataOperands(%[[CREATE]] : !fir.ref<!fir.array<?xf32>>)
+
   !$acc enter data create(a(5:10))
 !CHECK: %[[LB1:.*]] = arith.constant 4 : index
 !CHECK: %[[UB1:.*]] = arith.constant 9 : index
 !CHECK: %[[BOUND1:.*]] = acc.bounds lowerbound(%[[LB1]] : index) upperbound(%[[UB1]] : index)  startIdx(%c1{{.*}} : index)
 !CHECK: %[[CREATE1:.*]] = acc.create varPtr(%[[A]] : !fir.ref<!fir.array<10xf32>>) bounds(%[[BOUND1]]) -> !fir.ref<!fir.array<10xf32>> {name = "a(5:10)", structured = false}
 !CHECK: acc.enter_data dataOperands(%[[CREATE1]] : !fir.ref<!fir.array<10xf32>>)
 
   !$acc enter data create(b(n:m))