https://gcc.gnu.org/g:6589f31a914e75161c0e098ec3e129d9b8c6011a
commit r16-8907-g6589f31a914e75161c0e098ec3e129d9b8c6011a Author: Mikael Morin <[email protected]> Date: Thu May 7 20:48:26 2026 +0200 fortran: Add bounds checking code to the scalarizer block [PR125192] In gfc_conv_expr_descriptor, the array bounds checking code is added to the root block, which is a different block from the scalarizer block used to generate the array descriptor reference. This causes the array bounds checking code to come before, which can be problematic if the descriptor reference uses variables generated by the scalarizer, as they are used in bounds checking code before their definition in that case. This change adds the bounds checking code to the same block the scalarizer uses to generate the array descriptor reference, solving the use before definition problem. PR fortran/125192 PR fortran/125198 gcc/fortran/ChangeLog: * trans-array.cc (gfc_conv_expr_descriptor): Add bounds checking code to the outermost loop's preliminary block. gcc/testsuite/ChangeLog: * gfortran.dg/bounds_check_29.f90: New test. (cherry picked from commit 0c0c58310180b75a4ff23044006f7ddabe7f894c) Diff: --- gcc/fortran/trans-array.cc | 2 +- gcc/testsuite/gfortran.dg/bounds_check_29.f90 | 62 +++++++++++++++++++++++++++ 2 files changed, 63 insertions(+), 1 deletion(-) diff --git a/gcc/fortran/trans-array.cc b/gcc/fortran/trans-array.cc index 4f86ae2889bc..cb55e5082d4f 100644 --- a/gcc/fortran/trans-array.cc +++ b/gcc/fortran/trans-array.cc @@ -8652,7 +8652,7 @@ gfc_conv_expr_descriptor (gfc_se *se, gfc_expr *expr) /* Add bounds-checking for elemental dimensions. */ if ((gfc_option.rtcheck & GFC_RTCHECK_BOUNDS) && !expr->no_bounds_check) - array_bound_check_elemental (&se->pre, ss, expr); + array_bound_check_elemental (&outermost_loop (&loop)->pre, ss, expr); if (need_tmp) { diff --git a/gcc/testsuite/gfortran.dg/bounds_check_29.f90 b/gcc/testsuite/gfortran.dg/bounds_check_29.f90 new file mode 100644 index 000000000000..42ab7afaa470 --- /dev/null +++ b/gcc/testsuite/gfortran.dg/bounds_check_29.f90 @@ -0,0 +1,62 @@ +! { dg-do run } +! { dg-additional-options "-fcheck=bounds" } +! +! Check that if an array descriptor reference uses variables, they are +! not used uninitialized by the bounds-checking code. + + +! PR fortran/125192 +! Original example from Philippe Wautelet <philippe.wautelet at cnrs dot fr> + +subroutine boundcheck_bug + implicit none + + type isba_pe_t + real, pointer, dimension(:,:) :: xwg + end type isba_pe_t + type isba_npe_t + type(isba_pe_t), dimension(:), pointer :: al=>null() + end type isba_npe_t + type(isba_npe_t) :: npe + + allocate(npe%al(10)) + allocate(npe%al(1)%xwg(3,4)) + + call random_number( npe%al(1)%xwg(:,3) ) +end subroutine boundcheck_bug + + +! PR fortran/125198 +! Original example from Neil Carlson <neil.n.carlson at gmail dot com> + +module unstr_mesh_type + type unstr_mesh + real, allocatable :: normal(:,:) + contains + procedure :: compute_geometry + end type +contains + subroutine compute_geometry(this) + class(unstr_mesh), intent(inout) :: this + character(64) :: buf + !print *, this%normal(1,1) ! THIS IS OKAY + write(buf,*) this%normal(1,1) + if (trim(buf) /= ' 0.00000000') error stop 1 + !print *, this%normal(:,1) ! SPURIOUS BOUNDS ERROR HERE + write(buf,*) this%normal(:,1) + if (trim(buf) /= ' 0.00000000 0.00000000 0.00000000') error stop 2 + !if (any(this%normal(:,1) /= 0.0)) error stop 2 + end subroutine +end module + +subroutine test_pr125198 +use unstr_mesh_type +type(unstr_mesh) :: mesh +allocate(mesh%normal(3,10), source=0.0) +call mesh%compute_geometry +end subroutine + + +call boundcheck_bug +call test_pr125198 +end
