From: Harald Anlauf <anlauf@gmx.de>
Date: Sat, 20 Sep 2025 20:20:25 +0000 (+0200)
Subject: Fortran: fix issues with rank-2 deferred-length character arrays [PR108581]
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=749af11149623dbf9ba026fd98bd7f31409fdaed;p=thirdparty%2Fgcc.git

Fortran: fix issues with rank-2 deferred-length character arrays [PR108581]

	PR fortran/108581

gcc/fortran/ChangeLog:

	* trans-array.cc (gfc_conv_expr_descriptor): Take the dynamic
	string length into account when deriving the dataptr offset for
	a deferred-length character array.

gcc/testsuite/ChangeLog:

	* gfortran.dg/deferred_character_39.f90: New test.
---

diff --git a/gcc/fortran/trans-array.cc b/gcc/fortran/trans-array.cc
index abde05f5dde..0111c9566f4 100644
--- a/gcc/fortran/trans-array.cc
+++ b/gcc/fortran/trans-array.cc
@@ -8912,6 +8912,19 @@ gfc_conv_expr_descriptor (gfc_se *se, gfc_expr *expr)
 					  gfc_rank_cst[dim], stride);
 	}
 
+      /* For deferred-length character we need to take the dynamic length
+	 into account for the dataptr offset.  */
+      if (expr->ts.type == BT_CHARACTER
+	  && expr->ts.deferred
+	  && expr->ts.u.cl->backend_decl
+	  && VAR_P (expr->ts.u.cl->backend_decl))
+	{
+	  tree base_type = TREE_TYPE (base);
+	  base = fold_build2_loc (input_location, MULT_EXPR, base_type, base,
+				  fold_convert (base_type,
+						expr->ts.u.cl->backend_decl));
+	}
+
       for (n = loop.dimen; n < loop.dimen + codim; n++)
 	{
 	  from = loop.from[n];
diff --git a/gcc/testsuite/gfortran.dg/deferred_character_39.f90 b/gcc/testsuite/gfortran.dg/deferred_character_39.f90
new file mode 100644
index 00000000000..564f94bb9bd
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/deferred_character_39.f90
@@ -0,0 +1,239 @@
+! { dg-do run }
+! PR fortran/108581 - issues with rank-2 deferred-length character arrays
+
+program p
+  call pr108581
+  call test2
+end
+
+! Derived from original testcase
+subroutine pr108581
+  integer, parameter :: xmin = 0, xmax = 0
+  integer, parameter :: ymin = 0, ymax = 1
+  integer, parameter :: l = 2
+  integer            :: x, y
+  character(8)       :: line1, line2, line3
+  character(*),   parameter :: expect(ymin:ymax) = ['A.','B*']
+  character(len=:), pointer :: a(:,:) => NULL()
+
+  allocate (character(len=l) :: a(xmin:xmax, ymin:ymax))
+  a(xmin:xmax, ymin) = expect(ymin)
+  a(xmin:xmax, ymax) = expect(ymax)
+
+  do y = ymin, ymax
+     write(line1,'(4A)') (a(x, y), x = xmin, xmax)
+     write(line2,'(4A)')  a(xmin:xmax, y)
+     write(line3,'(4A)')  a(    :    , y)
+     if (line1 /= expect(y) .or. &
+         line2 /= expect(y) .or. &
+         line3 /= expect(y)      ) then
+        write(*,*) (a(x, y), x = xmin, xmax)
+        write(*,*)  a(xmin:xmax, y)
+        write(*,*)  a(    :    , y)
+        stop 1 + y
+     end if
+  enddo
+  call chk (a)
+  deallocate (a)
+contains
+  subroutine chk (z)
+    character(len=:), pointer :: z(:,:)
+    integer :: y
+    do y = lbound(z,2), ubound (z,2)
+       write(line2,'(4A)')  z(xmin:xmax, y)
+       write(line3,'(4A)')  z(    :    , y)
+       if (line2 /= expect(y) .or. &
+           line3 /= expect(y)      ) then
+          write(*,*) z(xmin:xmax, y)
+          write(*,*) z(    :    , y)
+          stop 5 + y
+       end if
+    enddo
+  end subroutine chk
+end
+
+! Exercise character kinds, strides, ...
+subroutine test2
+  implicit none
+  integer, parameter :: l = 3
+  integer            :: i
+
+  character(len=l,kind=1), parameter :: str1(*) = &
+       [   "123",   "456",   "789",   "0AB" ]
+  character(len=l,kind=4), parameter :: str4(*) = &
+       [ 4_"123", 4_"456", 4_"789", 4_"0AB" ]
+
+  character(len=l,kind=1), parameter :: str2(*,*) = &
+       reshape ([(str1(i),str1(5-i),i=1,4)], shape=[2,4])
+  character(len=l,kind=4), parameter :: str5(*,*) = &
+       reshape ([(str4(i),str4(5-i),i=1,4)], shape=[2,4])
+
+  character(len=l,kind=1), pointer :: a(:,:) => NULL(), e(:,:) => NULL()
+  character(len=:,kind=1), pointer :: b(:,:) => NULL(), f(:,:) => NULL()
+  character(len=l,kind=4), pointer :: c(:,:) => NULL(), g(:,:) => NULL()
+  character(len=:,kind=4), pointer :: d(:,:) => NULL(), h(:,:) => NULL()
+
+  character(len=16) :: s0, s1, s2, s3, s4
+
+  ! Simple case: shape=[1,4]
+  allocate (a, source = reshape (str1,[1,size(str1)]))
+  allocate (b, source = reshape (str1,[1,size(str1)]))
+  allocate (c, source = reshape (str4,[1,size(str4)]))
+! allocate (d, source=c)        ! ICE, tracked as pr121939
+  d => c
+  ! Positive non-unit stride
+  s0 = concat (str1(1::2))
+  write(s1,'(4A)') a(1,1::2)
+  write(s2,'(4A)') b(1,1::2)
+  write(s3,'(4A)') c(1,1::2)
+  write(s4,'(4A)') d(1,1::2)
+! print *, s0, s1, s2, s3, s4
+  if (s1 /= s0) stop 11
+  if (s2 /= s0) stop 12
+  if (s3 /= s0) stop 13
+  if (s4 /= s0) stop 14
+  s0 = concat (str1(2::2))
+  write(s1,'(4A)') a(1,2::2)
+  write(s2,'(4A)') b(1,2::2)
+  write(s3,'(4A)') c(1,2::2)
+  write(s4,'(4A)') d(1,2::2)
+! print *, s0, s1, s2, s3, s4
+  if (s1 /= s0) stop 15
+  if (s2 /= s0) stop 16
+  if (s3 /= s0) stop 17
+  if (s4 /= s0) stop 18
+
+  ! Negative non-unit stride
+  s0 = concat (str1(3:1:-2))
+  write(s1,'(4A)') a(1,3:1:-2)
+  write(s2,'(4A)') b(1,3:1:-2)
+  write(s3,'(4A)') c(1,3:1:-2)
+  write(s4,'(4A)') d(1,3:1:-2)
+! print *, s0, s1, s2, s3, s4
+  if (s1 /= s0) stop 21
+  if (s2 /= s0) stop 22
+  if (s3 /= s0) stop 23
+  if (s4 /= s0) stop 24
+  s0 = concat (str1(4:1:-2))
+  write(s1,'(4A)') a(1,4:1:-2)
+  write(s2,'(4A)') b(1,4:1:-2)
+  write(s3,'(4A)') c(1,4:1:-2)
+  write(s4,'(4A)') d(1,4:1:-2)
+! print *, s0, s1, s2, s3, s4
+  if (s1 /= s0) stop 25
+  if (s2 /= s0) stop 26
+  if (s3 /= s0) stop 27
+  if (s4 /= s0) stop 28
+  deallocate (a,b,c)
+
+  ! More complex cases with shape=[2,4]
+  allocate (e, source = reshape (str2,[2,size(str2,2)]))
+  allocate (f, source = reshape (str2,[2,size(str2,2)]))
+  allocate (g, source = reshape (str5,[2,size(str5,2)]))
+  h => g
+  s0 = concat (str2(1,3:1:-2))
+  write(s1,'(4A)') e(1,3:1:-2)
+  write(s2,'(4A)') f(1,3:1:-2)
+  write(s3,'(4A)') g(1,3:1:-2)
+  write(s4,'(4A)') h(1,3:1:-2)
+! print *, s0, s1, s2, s3, s4
+  if (s1 /= s0) stop 31
+  if (s2 /= s0) stop 32
+  if (s3 /= s0) stop 33
+  if (s4 /= s0) stop 34
+  s0 = concat (str2(1,4:1:-2))
+  write(s1,'(4A)') e(1,4:1:-2)
+  write(s2,'(4A)') f(1,4:1:-2)
+  write(s3,'(4A)') g(1,4:1:-2)
+  write(s4,'(4A)') h(1,4:1:-2)
+! print *, s0, s1, s2, s3, s4
+  if (s1 /= s0) stop 35
+  if (s2 /= s0) stop 36
+  if (s3 /= s0) stop 37
+  if (s4 /= s0) stop 38
+
+  s0 = concat (str2(2,3:1:-2))
+  write(s1,'(4A)') e(2,3:1:-2)
+  write(s2,'(4A)') f(2,3:1:-2)
+  write(s3,'(4A)') g(2,3:1:-2)
+  write(s4,'(4A)') h(2,3:1:-2)
+! print *, s0, s1, s2, s3, s4
+  if (s1 /= s0) stop 41
+  if (s2 /= s0) stop 42
+  if (s3 /= s0) stop 43
+  if (s4 /= s0) stop 44
+  s0 = concat (str2(2,4:1:-2))
+  write(s1,'(4A)') e(2,4:1:-2)
+  write(s2,'(4A)') f(2,4:1:-2)
+  write(s3,'(4A)') g(2,4:1:-2)
+  write(s4,'(4A)') h(2,4:1:-2)
+! print *, s0, s1, s2, s3, s4
+  if (s1 /= s0) stop 45
+  if (s2 /= s0) stop 46
+  if (s3 /= s0) stop 47
+  if (s4 /= s0) stop 48
+
+  ! Check pointer association with negative stride
+  a => e(2:1:-1,4:1:-1)
+  b => f(2:1:-1,4:1:-1)
+  c => g(2:1:-1,4:1:-1)
+  d => h(2:1:-1,4:1:-1)
+
+  s0 = concat (str2(2,4:1:-2))
+  write(s1,'(4A)') a(1,1::2)
+  write(s2,'(4A)') b(1,1::2)
+  write(s3,'(4A)') c(1,1::2)
+  write(s4,'(4A)') d(1,1::2)
+! print *, s0, s1, s2, s3, s4
+  if (s1 /= s0) stop 51
+  if (s2 /= s0) stop 52
+  if (s3 /= s0) stop 53
+  if (s4 /= s0) stop 54
+  s0 = concat (str2(2,3:1:-2))
+  write(s1,'(4A)') a(1,2::2)
+  write(s2,'(4A)') b(1,2::2)
+  write(s3,'(4A)') c(1,2::2)
+  write(s4,'(4A)') d(1,2::2)
+! print *, s0, s1, s2, s3, s4
+  if (s1 /= s0) stop 55
+  if (s2 /= s0) stop 56
+  if (s3 /= s0) stop 57
+  if (s4 /= s0) stop 58
+
+  s0 = concat (str2(1,4:1:-2))
+  write(s1,'(4A)') a(2,1::2)
+  write(s2,'(4A)') b(2,1::2)
+  write(s3,'(4A)') c(2,1::2)
+  write(s4,'(4A)') d(2,1::2)
+! print *, s0, s1, s2, s3, s4
+  if (s1 /= s0) stop 61
+  if (s2 /= s0) stop 62
+  if (s3 /= s0) stop 63
+  if (s4 /= s0) stop 64
+  s0 = concat (str2(1,3:1:-2))
+  write(s1,'(4A)') a(2,2::2)
+  write(s2,'(4A)') b(2,2::2)
+  write(s3,'(4A)') c(2,2::2)
+  write(s4,'(4A)') d(2,2::2)
+! print *, s0, s1, s2, s3, s4
+  if (s1 /= s0) stop 65
+  if (s2 /= s0) stop 66
+  if (s3 /= s0) stop 67
+  if (s4 /= s0) stop 68
+  deallocate (e,f,g)
+
+contains
+
+  ! Helper function to concatenate string array to scalar string
+  function concat (s)
+    character(len=:), allocatable :: concat
+    character(len=*), intent(in)  :: s(:)
+    integer :: i, l, n
+    n = size (s)
+    l = len  (s)
+    allocate (character(len=l*n) :: concat)
+    do i = 1, n
+       concat(1+(i-1)*l:i*l) = s(i)
+    end do
+  end function concat
+end