[gcc r11-9483] Fortran: handle expansion of zero-sized array constructors

[Harald Anlauf <anlauf@gcc.gnu.org>]

https://gcc.gnu.org/g:0351d851f791d81d85d4c366755e0662ea67dc97

commit r11-9483-g0351d851f791d81d85d4c366755e0662ea67dc97
Author: Harald Anlauf <anlauf@gmx.de>
Date:   Mon Jan 17 22:52:08 2022 +0100

    Fortran: handle expansion of zero-sized array constructors
    
    gcc/fortran/ChangeLog:
    
            PR fortran/103692
            * array.c (gfc_expand_constructor): Handle zero-sized array
            constructors.
    
    gcc/testsuite/ChangeLog:
    
            PR fortran/103692
            * gfortran.dg/pr102520.f90: Adjust error messages.
            * gfortran.dg/pr103692.f90: New test.
    
    (cherry picked from commit 0d01a2722671bef37b931fd1f121e44b27e68268)

Diff:
---
 gcc/fortran/array.c                    |  3 +++
 gcc/testsuite/gfortran.dg/pr102520.f90 |  6 ++----
 gcc/testsuite/gfortran.dg/pr103692.f90 | 23 +++++++++++++++++++++++
 3 files changed, 28 insertions(+), 4 deletions(-)

diff --git a/gcc/fortran/array.c b/gcc/fortran/array.c
index addd0ba5a56..b406f6d1f6e 100644
--- a/gcc/fortran/array.c
+++ b/gcc/fortran/array.c
@@ -1883,6 +1883,9 @@ gfc_expand_constructor (gfc_expr *e, bool fatal)
   gfc_expr *f;
   bool rc;
 
+  if (gfc_is_size_zero_array (e))
+    return true;
+
   /* If we can successfully get an array element at the max array size then
      the array is too big to expand, so we just return.  */
   f = gfc_get_array_element (e, flag_max_array_constructor);
diff --git a/gcc/testsuite/gfortran.dg/pr102520.f90 b/gcc/testsuite/gfortran.dg/pr102520.f90
index 1c98c185c17..d2ea8f3a424 100644
--- a/gcc/testsuite/gfortran.dg/pr102520.f90
+++ b/gcc/testsuite/gfortran.dg/pr102520.f90
@@ -5,8 +5,6 @@ program p
   type t
   end type
   type(t), parameter :: a(4)   = shape(1)         ! { dg-error "Incompatible" }
-  type(t), parameter :: b(2,2) = reshape(a,[2,2]) ! { dg-error "Incompatible" }
-  type(t), parameter :: c(2,2) = transpose(b)     ! { dg-error "Unclassifiable" }
+  type(t), parameter :: b(2,2) = reshape(a,[2,2]) ! { dg-error "must be an array" }
+  type(t), parameter :: c(2,2) = transpose(b)     ! { dg-error "must be of rank 2" }
 end
-
-! { dg-error "Different shape for array assignment" " " { target *-*-* } 7 }
diff --git a/gcc/testsuite/gfortran.dg/pr103692.f90 b/gcc/testsuite/gfortran.dg/pr103692.f90
new file mode 100644
index 00000000000..9687a3cec9d
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/pr103692.f90
@@ -0,0 +1,23 @@
+! { dg-do compile }
+! { dg-options "-fdump-tree-original" }
+! PR fortran/103692 - ICE in expand_constructor
+! Contributed by G.Steinmetz
+
+program p
+  character(3), parameter :: a(4) = 'abc'
+  character(*), parameter :: b(*) =  (a(2:1))
+  character(*), parameter :: y(*) = [(a(2:1))]
+  character(*), parameter :: u(*) =  a(2:1)
+  character(*), parameter :: v(*) = [a(2:1)]
+  character(*), parameter :: w(-1) = (a(2:1))
+  character(*), parameter :: x(-1) =  a(2:1)
+  character(5), parameter :: c(3,3) = 'def'
+  character(*), parameter :: d(*)   = [(c(2:1,2:))]
+  character(*), parameter :: e(*,*) =  (c(2:1,2:))
+  if (len(b) /= 3 .or. size (b) /= 0) stop 1
+  if (len(y) /= 3 .or. size (y) /= 0) stop 2
+  if (len(d) /= 5 .or. size (d) /= 0) stop 3
+  if (len(e) /= 5 .or. any (shape (e) /= [0,2])) stop 4
+end
+
+! { dg-final { scan-tree-dump-not "_gfortran_stop_numeric" "original" } }