[flang] use hlfir base when translating assumed-rank entity to fir::ExtendedValue (#94822)

The hlfir::Entity to fir::ExtendedValue conversion usually uses the "fir
base" output of hlfir.declare (which is the same as the input) to avoid
introducing temporary descriptors for the sole purpose of introducing
updating lower bound information. This is possible because local lower
bounds, if any, are tracked in a vector inside the fir::ExtendedValue.

With assumed-ranks, the lower bounds cannot be tracked inside the
fir::ExtendedValue vector (their numbers is unknown at compile time).
Hence, the fir.box/fir.class used in fir::ExtendedValue in lowering must
always contain accurate local lower bound information.

Author: jeanPerier

flang/lib/Optimizer/Builder/HLFIRTools.cpp

@@ -882,10 +882,15 @@ static fir::ExtendedValue translateVariableToExtendedValue(
     mlir::Location loc, fir::FirOpBuilder &builder, hlfir::Entity variable,
     bool forceHlfirBase = false, bool contiguousHint = false) {
   assert(variable.isVariable() && "must be a variable");
-  /// When going towards FIR, use the original base value to avoid
-  /// introducing descriptors at runtime when they are not required.
-  mlir::Value base =
-      forceHlfirBase ? variable.getBase() : variable.getFirBase();
+  // When going towards FIR, use the original base value to avoid
+  // introducing descriptors at runtime when they are not required.
+  // This is not done for assumed-rank since the fir::ExtendedValue cannot
+  // held the related lower bounds in an vector. The lower bounds of the
+  // descriptor must always be used instead.
+
+  mlir::Value base = (forceHlfirBase || variable.isAssumedRank())
+                         ? variable.getBase()
+                         : variable.getFirBase();
   if (variable.isMutableBox())
     return fir::MutableBoxValue(base, getExplicitTypeParams(variable),
                                 fir::MutableProperties{});

flang/test/Lower/HLFIR/assumed-rank-inquiries-2.f90

@@ -29,7 +29,7 @@ subroutine test_size_4(x)
 ! CHECK-SAME:                              %[[VAL_0:.*]]: !fir.box<!fir.array<*:f32>> {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 = "_QFtest_size_1Ex"} : (!fir.box<!fir.array<*:f32>>, !fir.dscope) -> (!fir.box<!fir.array<*:f32>>, !fir.box<!fir.array<*:f32>>)
-! CHECK:           %[[VAL_5:.*]] = fir.convert %[[VAL_2]]#1 : (!fir.box<!fir.array<*:f32>>) -> !fir.box<none>
+! CHECK:           %[[VAL_5:.*]] = fir.convert %[[VAL_2]]#0 : (!fir.box<!fir.array<*:f32>>) -> !fir.box<none>
 ! CHECK:           %[[VAL_7:.*]] = fir.call @_FortranASize(%[[VAL_5]]
 ! CHECK:           %[[VAL_8:.*]] = fir.convert %[[VAL_7]] : (i64) -> i32
 ! CHECK:           %[[VAL_9:.*]]:3 = hlfir.associate %[[VAL_8]] {adapt.valuebyref} : (i32) -> (!fir.ref<i32>, !fir.ref<i32>, i1)
@@ -49,13 +49,13 @@ subroutine test_size_4(x)
 ! CHECK:           %[[VAL_6:.*]] = arith.constant 0 : i64
 ! CHECK:           %[[VAL_7:.*]] = arith.cmpi eq, %[[VAL_5]], %[[VAL_6]] : i64
 ! CHECK:           %[[VAL_8:.*]] = fir.if %[[VAL_7]] -> (i32) {
-! CHECK:             %[[VAL_11:.*]] = fir.convert %[[VAL_3]]#1 : (!fir.box<!fir.array<*:f32>>) -> !fir.box<none>
+! CHECK:             %[[VAL_11:.*]] = fir.convert %[[VAL_3]]#0 : (!fir.box<!fir.array<*:f32>>) -> !fir.box<none>
 ! CHECK:             %[[VAL_13:.*]] = fir.call @_FortranASize(%[[VAL_11]]
 ! CHECK:             %[[VAL_14:.*]] = fir.convert %[[VAL_13]] : (i64) -> i32
 ! CHECK:             fir.result %[[VAL_14]] : i32
 ! CHECK:           } else {
 ! CHECK:             %[[VAL_15:.*]] = fir.load %[[VAL_1]] : !fir.ref<i32>
-! CHECK:             %[[VAL_18:.*]] = fir.convert %[[VAL_3]]#1 : (!fir.box<!fir.array<*:f32>>) -> !fir.box<none>
+! CHECK:             %[[VAL_18:.*]] = fir.convert %[[VAL_3]]#0 : (!fir.box<!fir.array<*:f32>>) -> !fir.box<none>
 ! CHECK:             %[[VAL_20:.*]] = fir.call @_FortranASizeDim(%[[VAL_18]]
 ! CHECK:             %[[VAL_21:.*]] = fir.convert %[[VAL_20]] : (i64) -> i32
 ! CHECK:             fir.result %[[VAL_21]] : i32
@@ -76,13 +76,13 @@ subroutine test_size_4(x)
 ! CHECK:           %[[VAL_6:.*]] = arith.constant 0 : i64
 ! CHECK:           %[[VAL_7:.*]] = arith.cmpi eq, %[[VAL_5]], %[[VAL_6]] : i64
 ! CHECK:           %[[VAL_8:.*]] = fir.if %[[VAL_7]] -> (i32) {
-! CHECK:             %[[VAL_11:.*]] = fir.convert %[[VAL_4]]#1 : (!fir.box<!fir.array<*:f32>>) -> !fir.box<none>
+! CHECK:             %[[VAL_11:.*]] = fir.convert %[[VAL_4]]#0 : (!fir.box<!fir.array<*:f32>>) -> !fir.box<none>
 ! CHECK:             %[[VAL_13:.*]] = fir.call @_FortranASize(%[[VAL_11]],
 ! CHECK:             %[[VAL_14:.*]] = fir.convert %[[VAL_13]] : (i64) -> i32
 ! CHECK:             fir.result %[[VAL_14]] : i32
 ! CHECK:           } else {
 ! CHECK:             %[[VAL_15:.*]] = fir.load %[[VAL_3]]#1 : !fir.ref<i32>
-! CHECK:             %[[VAL_18:.*]] = fir.convert %[[VAL_4]]#1 : (!fir.box<!fir.array<*:f32>>) -> !fir.box<none>
+! CHECK:             %[[VAL_18:.*]] = fir.convert %[[VAL_4]]#0 : (!fir.box<!fir.array<*:f32>>) -> !fir.box<none>
 ! CHECK:             %[[VAL_20:.*]] = fir.call @_FortranASizeDim(%[[VAL_18]]
 ! CHECK:             %[[VAL_21:.*]] = fir.convert %[[VAL_20]] : (i64) -> i32
 ! CHECK:             fir.result %[[VAL_21]] : i32
@@ -97,7 +97,7 @@ subroutine test_size_4(x)
 ! CHECK-SAME:                              %[[VAL_0:.*]]: !fir.ref<!fir.box<!fir.heap<!fir.array<*:f32>>>> {fir.bindc_name = "x"}) {
 ! CHECK:           %[[VAL_1:.*]] = fir.dummy_scope : !fir.dscope
 ! CHECK:           %[[VAL_2:.*]]:2 = hlfir.declare %[[VAL_0]] dummy_scope %[[VAL_1]] {fortran_attrs = #fir.var_attrs<allocatable>, uniq_name = "_QFtest_size_4Ex"} : (!fir.ref<!fir.box<!fir.heap<!fir.array<*:f32>>>>, !fir.dscope) -> (!fir.ref<!fir.box<!fir.heap<!fir.array<*:f32>>>>, !fir.ref<!fir.box<!fir.heap<!fir.array<*:f32>>>>)
-! CHECK:           %[[VAL_3:.*]] = fir.load %[[VAL_2]]#1 : !fir.ref<!fir.box<!fir.heap<!fir.array<*:f32>>>>
+! CHECK:           %[[VAL_3:.*]] = fir.load %[[VAL_2]]#0 : !fir.ref<!fir.box<!fir.heap<!fir.array<*:f32>>>>
 ! CHECK:           %[[VAL_6:.*]] = fir.convert %[[VAL_3]] : (!fir.box<!fir.heap<!fir.array<*:f32>>>) -> !fir.box<none>
 ! CHECK:           %[[VAL_8:.*]] = fir.call @_FortranASize(%[[VAL_6]]
 ! CHECK:           %[[VAL_9:.*]] = fir.convert %[[VAL_8]] : (i64) -> i32