[gcc r15-658] Fortran: Fix SHAPE for zero-size arrays

[Tobias Burnus via Gcc-cvs]

https://gcc.gnu.org/g:b701306a9b38bd74cdc26c7ece5add22f2203b56

commit r15-658-gb701306a9b38bd74cdc26c7ece5add22f2203b56
Author: Tobias Burnus <tbur...@baylibre.com>
Date:   Mon May 20 08:34:48 2024 +0200

    Fortran: Fix SHAPE for zero-size arrays
    
            PR fortran/115150
    
    gcc/fortran/ChangeLog:
    
            * trans-intrinsic.cc (gfc_conv_intrinsic_bound): Fix SHAPE
            for zero-size arrays
    
    gcc/testsuite/ChangeLog:
    
            * gfortran.dg/shape_12.f90: New test.

Diff:
---
 gcc/fortran/trans-intrinsic.cc         |  4 ++-
 gcc/testsuite/gfortran.dg/shape_12.f90 | 51 ++++++++++++++++++++++++++++++++++
 2 files changed, 54 insertions(+), 1 deletion(-)

diff --git a/gcc/fortran/trans-intrinsic.cc b/gcc/fortran/trans-intrinsic.cc
index 80dc3426ab04..912c1000e186 100644
--- a/gcc/fortran/trans-intrinsic.cc
+++ b/gcc/fortran/trans-intrinsic.cc
@@ -3090,7 +3090,9 @@ gfc_conv_intrinsic_bound (gfc_se * se, gfc_expr * expr, 
enum gfc_isym_id op)
                                      lbound, gfc_index_one_node);
        }
       else if (op == GFC_ISYM_SHAPE)
-       se->expr = size;
+       se->expr = fold_build2_loc (input_location, MAX_EXPR,
+                                   gfc_array_index_type, size,
+                                   gfc_index_zero_node);
       else
        gcc_unreachable ();
 
diff --git a/gcc/testsuite/gfortran.dg/shape_12.f90 
b/gcc/testsuite/gfortran.dg/shape_12.f90
new file mode 100644
index 000000000000..e672e1ff9f95
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/shape_12.f90
@@ -0,0 +1,51 @@
+! { dg-do run }
+!
+! PR fortran/115150
+!
+! Check that SHAPE handles zero-sized arrays correctly
+!
+implicit none
+call one
+call two
+
+contains
+
+subroutine one
+  real,allocatable :: A(:),B(:,:)
+  allocate(a(3:0), b(5:1, 2:5))
+
+  if (any (shape(a) /= [0])) stop 1
+  if (any (shape(b) /= [0, 4])) stop 2
+  if (size(a) /= 0) stop 3
+  if (size(b) /= 0) stop 4
+  if (any (lbound(a) /= [1])) stop 5
+  if (any (lbound(b) /= [1, 2])) stop 6
+  if (any (ubound(a) /= [0])) stop 5
+  if (any (ubound(b) /= [0,5])) stop 6
+end
+
+subroutine two
+integer :: x1(10), x2(10,10)
+call f(x1, x2, -3)
+end
+
+subroutine f(y1, y2, n)
+  integer, value :: n
+  integer :: y1(1:n)
+  integer :: y2(1:n,4,2:*)
+  call g(y1, y2)
+end
+
+subroutine g(z1, z2)
+  integer :: z1(..), z2(..)
+
+  if (any (shape(z1) /= [0])) stop 1
+  if (any (shape(z2) /= [0, 4, -1])) stop 2
+  if (size(z1) /= 0) stop 3
+  if (size(z2) /= 0) stop 4
+  if (any (lbound(z1) /= [1])) stop 5
+  if (any (lbound(z2) /= [1, 1, 1])) stop 6
+  if (any (ubound(z1) /= [0])) stop 5
+  if (any (ubound(z2) /= [0, 4, -1])) stop 6
+end
+end