From 04a1259ffea29718256beeb2aca3f473c1f259e4 Mon Sep 17 00:00:00 2001 From: Mikael Morin Date: Wed, 30 Jul 2025 11:02:27 +0200 Subject: [PATCH] fortran: Evaluate class function bounds in the scalarizer [PR121342] There is code in gfc_conv_procedure_call that, for polymorphic functions, initializes the scalarization array descriptor information and forcedfully sets loop bounds. This code is changing the decisions made by the scalarizer behind his back, and the test shows an example where the consequences are (badly) visible. In the test, for one of the actual arguments to an elemental subroutine, an offset to the loop variable is missing to access the array, as it was the one originally chosen to set the loop bounds from. This could theoretically be fixed by just clearing the array of choice for the loop bounds. This change takes instead the harder path of adding the missing information to the scalarizer's knowledge so that its decision doesn't need to be forced to something else after the fact. The array descriptor information initialisation for polymorphic functions is moved to gfc_add_loop_ss_code (after the function call generation), and the loop bounds initialization to a new function called after that. As the array chosen to set the loop bounds from is no longer forced to be the polymorphic function result, we have to let the scalarizer set a delta for polymorphic function results. For regular non-polymorphic function result arrays, they are zero-based and the temporary creation makes the loop zero-based as well, so we can continue to skip the delta calculation. In the cases where a temporary is created to store the result of the array function, the creation of the temporary shifts the loop bounds to be zero-based. As there was no delta for polymorphic result arrays, the function result descriptor offset was set to zero in that case for a zero-based array reference to be correct. Now that the scalarizer sets a delta, those forced offset updates have to go because they can make the descriptor invalid and cause erroneous array references. PR fortran/121342 gcc/fortran/ChangeLog: * trans-expr.cc (gfc_conv_subref_array_arg): Remove offset update. (gfc_conv_procedure_call): For polymorphic functions, move the scalarizer descriptor information... * trans-array.cc (gfc_add_loop_ss_code): ... here, and evaluate the bounds to fresh variables. (get_class_info_from_ss): Remove offset update. (gfc_conv_ss_startstride): Don't set a zero value for function result upper bounds. (late_set_loop_bounds): New. (gfc_conv_loop_setup): If the bounds of a function result have been set, and no other array provided loop bounds for a dimension, use the function result bounds as loop bounds for that dimension. (gfc_set_delta): Don't skip delta setting for polymorphic function results. gcc/testsuite/ChangeLog: * gfortran.dg/class_elemental_1.f90: New test. --- gcc/fortran/trans-array.cc | 116 ++++++++++++++---- gcc/fortran/trans-expr.cc | 35 +----- .../gfortran.dg/class_elemental_1.f90 | 35 ++++++ 3 files changed, 132 insertions(+), 54 deletions(-) create mode 100644 gcc/testsuite/gfortran.dg/class_elemental_1.f90 diff --git a/gcc/fortran/trans-array.cc b/gcc/fortran/trans-array.cc index 0f7637dd535..990aaaffb50 100644 --- a/gcc/fortran/trans-array.cc +++ b/gcc/fortran/trans-array.cc @@ -1426,12 +1426,6 @@ get_class_info_from_ss (stmtblock_t * pre, gfc_ss *ss, tree *eltype, tmp2 = gfc_class_len_get (class_expr); gfc_add_modify (pre, tmp, tmp2); } - - if (rhs_function) - { - tmp = gfc_class_data_get (class_expr); - gfc_conv_descriptor_offset_set (pre, tmp, gfc_index_zero_node); - } } else if (rhs_ss->info->data.array.descriptor) { @@ -3372,18 +3366,51 @@ gfc_add_loop_ss_code (gfc_loopinfo * loop, gfc_ss * ss, bool subscript, break; case GFC_SS_FUNCTION: - /* Array function return value. We call the function and save its - result in a temporary for use inside the loop. */ - gfc_init_se (&se, NULL); - se.loop = loop; - se.ss = ss; - if (gfc_is_class_array_function (expr)) - expr->must_finalize = 1; - gfc_conv_expr (&se, expr); - gfc_add_block_to_block (&outer_loop->pre, &se.pre); - gfc_add_block_to_block (&outer_loop->post, &se.post); - gfc_add_block_to_block (&outer_loop->post, &se.finalblock); - ss_info->string_length = se.string_length; + { + /* Array function return value. We call the function and save its + result in a temporary for use inside the loop. */ + gfc_init_se (&se, NULL); + se.loop = loop; + se.ss = ss; + bool class_func = gfc_is_class_array_function (expr); + if (class_func) + expr->must_finalize = 1; + gfc_conv_expr (&se, expr); + gfc_add_block_to_block (&outer_loop->pre, &se.pre); + if (class_func + && se.expr + && GFC_CLASS_TYPE_P (TREE_TYPE (se.expr))) + { + tree tmp = gfc_class_data_get (se.expr); + info->descriptor = tmp; + info->data = gfc_conv_descriptor_data_get (tmp); + info->offset = gfc_conv_descriptor_offset_get (tmp); + for (gfc_ss *s = ss; s; s = s->parent) + for (int n = 0; n < s->dimen; n++) + { + int dim = s->dim[n]; + tree tree_dim = gfc_rank_cst[dim]; + + tree start; + start = gfc_conv_descriptor_lbound_get (tmp, tree_dim); + start = gfc_evaluate_now (start, &outer_loop->pre); + info->start[dim] = start; + + tree end; + end = gfc_conv_descriptor_ubound_get (tmp, tree_dim); + end = gfc_evaluate_now (end, &outer_loop->pre); + info->end[dim] = end; + + tree stride; + stride = gfc_conv_descriptor_stride_get (tmp, tree_dim); + stride = gfc_evaluate_now (stride, &outer_loop->pre); + info->stride[dim] = stride; + } + } + gfc_add_block_to_block (&outer_loop->post, &se.post); + gfc_add_block_to_block (&outer_loop->post, &se.finalblock); + ss_info->string_length = se.string_length; + } break; case GFC_SS_CONSTRUCTOR: @@ -5383,7 +5410,8 @@ done: int dim = ss->dim[n]; info->start[dim] = gfc_index_zero_node; - info->end[dim] = gfc_index_zero_node; + if (ss_info->type != GFC_SS_FUNCTION) + info->end[dim] = gfc_index_zero_node; info->stride[dim] = gfc_index_one_node; } break; @@ -6068,6 +6096,46 @@ set_loop_bounds (gfc_loopinfo *loop) } +/* Last attempt to set the loop bounds, in case they depend on an allocatable + function result. */ + +static void +late_set_loop_bounds (gfc_loopinfo *loop) +{ + int n, dim; + gfc_array_info *info; + gfc_ss **loopspec; + + loopspec = loop->specloop; + + for (n = 0; n < loop->dimen; n++) + { + /* Set the extents of this range. */ + if (loop->from[n] == NULL_TREE + || loop->to[n] == NULL_TREE) + { + /* We should have found the scalarization loop specifier. If not, + that's bad news. */ + gcc_assert (loopspec[n]); + + info = &loopspec[n]->info->data.array; + dim = loopspec[n]->dim[n]; + + if (loopspec[n]->info->type == GFC_SS_FUNCTION + && info->start[dim] + && info->end[dim]) + { + loop->from[n] = info->start[dim]; + loop->to[n] = info->end[dim]; + } + } + } + + for (loop = loop->nested; loop; loop = loop->next) + late_set_loop_bounds (loop); +} + + /* Initialize the scalarization loop. Creates the loop variables. Determines the range of the loop variables. Creates a temporary if required. Also generates code for scalar expressions which have been @@ -6086,6 +6154,8 @@ gfc_conv_loop_setup (gfc_loopinfo * loop, locus * where) allocating the temporary. */ gfc_add_loop_ss_code (loop, loop->ss, false, where); + late_set_loop_bounds (loop); + tmp_ss = loop->temp_ss; /* If we want a temporary then create it. */ if (tmp_ss != NULL) @@ -6142,9 +6212,11 @@ gfc_set_delta (gfc_loopinfo *loop) gfc_ss_type ss_type; ss_type = ss->info->type; - if (ss_type != GFC_SS_SECTION - && ss_type != GFC_SS_COMPONENT - && ss_type != GFC_SS_CONSTRUCTOR) + if (!(ss_type == GFC_SS_SECTION + || ss_type == GFC_SS_COMPONENT + || ss_type == GFC_SS_CONSTRUCTOR + || (ss_type == GFC_SS_FUNCTION + && gfc_is_class_array_function (ss->info->expr)))) continue; info = &ss->info->data.array; diff --git a/gcc/fortran/trans-expr.cc b/gcc/fortran/trans-expr.cc index 0db7ba3fd52..ec240844a5e 100644 --- a/gcc/fortran/trans-expr.cc +++ b/gcc/fortran/trans-expr.cc @@ -5485,16 +5485,6 @@ gfc_conv_subref_array_arg (gfc_se *se, gfc_expr * expr, int g77, /* Translate the expression. */ gfc_conv_expr (&rse, expr); - /* Reset the offset for the function call since the loop - is zero based on the data pointer. Note that the temp - comes first in the loop chain since it is added second. */ - if (gfc_is_class_array_function (expr)) - { - tmp = loop.ss->loop_chain->info->data.array.descriptor; - gfc_conv_descriptor_offset_set (&loop.pre, tmp, - gfc_index_zero_node); - } - gfc_conv_tmp_array_ref (&lse); if (intent != INTENT_OUT) @@ -8864,28 +8854,9 @@ gfc_conv_procedure_call (gfc_se * se, gfc_symbol * sym, && se->expr && GFC_CLASS_TYPE_P (TREE_TYPE (se->expr)) && expr->must_finalize) { - int n; - if (se->ss && se->ss->loop) - { - gfc_add_block_to_block (&se->ss->loop->pre, &se->pre); - se->expr = gfc_evaluate_now (se->expr, &se->ss->loop->pre); - tmp = gfc_class_data_get (se->expr); - info->descriptor = tmp; - info->data = gfc_conv_descriptor_data_get (tmp); - info->offset = gfc_conv_descriptor_offset_get (tmp); - for (n = 0; n < se->ss->loop->dimen; n++) - { - tree dim = gfc_rank_cst[n]; - se->ss->loop->to[n] = gfc_conv_descriptor_ubound_get (tmp, dim); - se->ss->loop->from[n] = gfc_conv_descriptor_lbound_get (tmp, dim); - } - } - else - { - /* TODO Eliminate the doubling of temporaries. This - one is necessary to ensure no memory leakage. */ - se->expr = gfc_evaluate_now (se->expr, &se->pre); - } + /* TODO Eliminate the doubling of temporaries. This + one is necessary to ensure no memory leakage. */ + se->expr = gfc_evaluate_now (se->expr, &se->pre); /* Finalize the result, if necessary. */ attr = expr->value.function.esym diff --git a/gcc/testsuite/gfortran.dg/class_elemental_1.f90 b/gcc/testsuite/gfortran.dg/class_elemental_1.f90 new file mode 100644 index 00000000000..547ae989218 --- /dev/null +++ b/gcc/testsuite/gfortran.dg/class_elemental_1.f90 @@ -0,0 +1,35 @@ +! { dg-do run } +! +! PR fortran/121342 +! The polymorphic function result as actual argument used to force the loop +! bounds around the elemental call, altering access to the other arrays. + +program p + implicit none + type :: t + integer :: i + end type + type :: u + integer :: i, a + end type + type(u) :: accum(5) + integer :: a(3:7), k + a = [ (k*k, k=1,5) ] + call s(accum, f(), a) + ! print *, accum%i + ! print *, accum%a + if (any(accum%i /= accum%a)) error stop 1 +contains + elemental subroutine s(l, c, a) + type(u) , intent(out) :: l + class(t) , intent(in) :: c + integer , intent(in) :: a + l%i = c%i + l%a = a + end subroutine + function f() + class(t), allocatable :: f(:) + allocate(f(-1:3)) + f%i = [ (k*k, k=1,5) ] + end function +end program -- 2.47.2