[flang] prevent legacy lowering from being called in pointer assignment

[jeanPerier]

When doing a pointer assignment with an RHS that is an array section, the code fell in the legacy lowering code even with HLFIR enabled. Escape this old code when HLFIR is on.

Should fix #80884.

[llvmbot]

@llvm/pr-subscribers-flang-fir-hlfir

Author: None (jeanPerier)

Changes

When doing a pointer assignment with an RHS that is an array section, the code fell in the legacy lowering code even with HLFIR enabled. Escape this old code when HLFIR is on.

Should fix #80884.

---

Full diff: https://github.com/llvm/llvm-project/pull/81750.diff

2 Files Affected:

• (modified) flang/lib/Lower/Bridge.cpp (+8-1)
• (added) flang/test/Lower/HLFIR/issue80884.f90 (+32)

diff --git a/flang/lib/Lower/Bridge.cpp b/flang/lib/Lower/Bridge.cpp
index 76e127207d764e..2d7f748cefa2d8 100644
--- a/flang/lib/Lower/Bridge.cpp
+++ b/flang/lib/Lower/Bridge.cpp
@@ -3419,6 +3419,13 @@ class FirConverter : public Fortran::lower::AbstractConverter {
       fir::factory::disassociateMutableBox(*builder, loc, lhs);
       return;
     }
+    if (lowerToHighLevelFIR()) {
+      fir::ExtendedValue rhs = genExprAddr(assign.rhs, stmtCtx);
+      fir::factory::associateMutableBoxWithRemap(*builder, loc, lhs, rhs,
+                                                 lbounds, ubounds);
+      return;
+    }
+    // Legacy lowering below.
     // Do not generate a temp in case rhs is an array section.
     fir::ExtendedValue rhs =
         Fortran::lower::isArraySectionWithoutVectorSubscript(assign.rhs)
@@ -3427,7 +3434,7 @@ class FirConverter : public Fortran::lower::AbstractConverter {
             : genExprAddr(assign.rhs, stmtCtx);
     fir::factory::associateMutableBoxWithRemap(*builder, loc, lhs, rhs, lbounds,
                                                ubounds);
-    if (!lowerToHighLevelFIR() && explicitIterationSpace()) {
+    if (explicitIterationSpace()) {
       mlir::ValueRange inners = explicitIterSpace.getInnerArgs();
       if (!inners.empty())
         builder->create<fir::ResultOp>(loc, inners);
diff --git a/flang/test/Lower/HLFIR/issue80884.f90 b/flang/test/Lower/HLFIR/issue80884.f90
new file mode 100644
index 00000000000000..2a7792b6004c4d
--- /dev/null
+++ b/flang/test/Lower/HLFIR/issue80884.f90
@@ -0,0 +1,32 @@
+! Test lowering of pointer remapping with component ref in the RHS.
+! RUN: bbc -emit-hlfir -o - %s -I nw | FileCheck %s
+
+subroutine issue80884(p, targ)
+  type t0
+    real :: array(10, 10)
+  end type
+  type, extends(t0) :: t
+  end type
+  type(t), target :: targ
+  real, pointer :: p(:)
+  p(1:100) => targ%array
+end subroutine
+! CHECK-LABEL:   func.func @_QPissue80884(
+! CHECK:           %[[VAL_2:.*]]:2 = hlfir.declare %{{.*}} {fortran_attrs = #fir.var_attrs<pointer>, uniq_name = "_QFissue80884Ep"} : (!fir.ref<!fir.box<!fir.ptr<!fir.array<?xf32>>>>) -> (!fir.ref<!fir.box<!fir.ptr<!fir.array<?xf32>>>>, !fir.ref<!fir.box<!fir.ptr<!fir.array<?xf32>>>>)
+! CHECK:           %[[VAL_3:.*]]:2 = hlfir.declare %{{.*}} {fortran_attrs = #fir.var_attrs<target>, uniq_name = "_QFissue80884Etarg"} : (!fir.ref<!fir.type<_QFissue80884Tt{t0:!fir.type<_QFissue80884Tt0{array:!fir.array<10x10xf32>}>}>>) -> (!fir.ref<!fir.type<_QFissue80884Tt{t0:!fir.type<_QFissue80884Tt0{array:!fir.array<10x10xf32>}>}>>, !fir.ref<!fir.type<_QFissue80884Tt{t0:!fir.type<_QFissue80884Tt0{array:!fir.array<10x10xf32>}>}>>)
+! CHECK:           %[[VAL_4:.*]] = arith.constant 1 : i64
+! CHECK:           %[[VAL_5:.*]] = arith.constant 100 : i64
+! CHECK:           %[[VAL_6:.*]] = hlfir.designate %[[VAL_3]]#0{"t0"}   : (!fir.ref<!fir.type<_QFissue80884Tt{t0:!fir.type<_QFissue80884Tt0{array:!fir.array<10x10xf32>}>}>>) -> !fir.ref<!fir.type<_QFissue80884Tt0{array:!fir.array<10x10xf32>}>>
+! CHECK:           %[[VAL_7:.*]] = arith.constant 10 : index
+! CHECK:           %[[VAL_8:.*]] = arith.constant 10 : index
+! CHECK:           %[[VAL_9:.*]] = fir.shape %[[VAL_7]], %[[VAL_8]] : (index, index) -> !fir.shape<2>
+! CHECK:           %[[VAL_10:.*]] = hlfir.designate %[[VAL_6]]{"array"}   shape %[[VAL_9]] : (!fir.ref<!fir.type<_QFissue80884Tt0{array:!fir.array<10x10xf32>}>>, !fir.shape<2>) -> !fir.ref<!fir.array<10x10xf32>>
+! CHECK:           %[[VAL_11:.*]] = arith.constant 1 : index
+! CHECK:           %[[VAL_12:.*]] = fir.convert %[[VAL_4]] : (i64) -> index
+! CHECK:           %[[VAL_13:.*]] = fir.convert %[[VAL_5]] : (i64) -> index
+! CHECK:           %[[VAL_14:.*]] = arith.subi %[[VAL_13]], %[[VAL_12]] : index
+! CHECK:           %[[VAL_15:.*]] = arith.addi %[[VAL_14]], %[[VAL_11]] : index
+! CHECK:           %[[VAL_16:.*]] = fir.convert %[[VAL_10]] : (!fir.ref<!fir.array<10x10xf32>>) -> !fir.ref<!fir.array<?xf32>>
+! CHECK:           %[[VAL_17:.*]] = fir.shape_shift %[[VAL_4]], %[[VAL_15]] : (i64, index) -> !fir.shapeshift<1>
+! CHECK:           %[[VAL_18:.*]] = fir.embox %[[VAL_16]](%[[VAL_17]]) : (!fir.ref<!fir.array<?xf32>>, !fir.shapeshift<1>) -> !fir.box<!fir.ptr<!fir.array<?xf32>>>
+! CHECK:           fir.store %[[VAL_18]] to %[[VAL_2]]#1 : !fir.ref<!fir.box<!fir.ptr<!fir.array<?xf32>>>>

[psteinfeld]

All builds and tests correctly and looks good.

I did not try the code from bug #80884, though.