2007-07-28 Paul Thomas <pault@gcc.gnu.org>

	PR fortran/32880
	* trans-expr.c (gfc_trans_scalar_assign): Revert to fixed order
	for lse and rse pre expressions, for derived types with
	allocatable components.  Instead, assign the lhs to a temporary
	and deallocate after the assignment.

2007-07-28  Paul Thomas  <pault@gcc.gnu.org>

	PR fortran/32880
	* gfortran.dg/alloc_comp_assign_6.f90: New test.


git-svn-id: https://gcc.gnu.org/svn/gcc/trunk@127011 138bc75d-0d04-0410-961f-82ee72b054a4

4 files changed, 76 insertions, 13 deletions

diff --git a/gcc/fortran/ChangeLog b/gcc/fortran/ChangeLog
index 29c134d8c06..5f8e39da7d3 100644
--- a/gcc/fortran/ChangeLog
+++ b/gcc/fortran/ChangeLog
@@ -1,3 +1,11 @@
+2007-07-28  Paul Thomas  <pault@gcc.gnu.org>
+
+	PR fortran/32880
+	* trans-expr.c (gfc_trans_scalar_assign): Revert to fixed order
+	for lse and rse pre expressions, for derived types with
+	allocatable components.  Instead, assign the lhs to a temporary
+	and deallocate after the assignment.
+
 2007-07-28  Janne Blomqvist  <jb@gcc.gnu.org>
 
 	PR fortran/32909
diff --git a/gcc/fortran/trans-expr.c b/gcc/fortran/trans-expr.c
index 2436574aa3d..528bf39dbe6 100644
--- a/gcc/fortran/trans-expr.c
+++ b/gcc/fortran/trans-expr.c
@@ -3512,25 +3512,20 @@ gfc_trans_scalar_assign (gfc_se * lse, gfc_se * rse, gfc_typespec ts,
 	}
 
       /* Deallocate the lhs allocated components as long as it is not
-	 the same as the rhs.  */
+	 the same as the rhs.  This must be done following the assignment
+	 to prevent deallocating data that could be used in the rhs
+	 expression.  */
       if (!l_is_temp)
 	{
-	  tmp = gfc_deallocate_alloc_comp (ts.derived, lse->expr, 0);
+	  tmp = gfc_evaluate_now (lse->expr, &lse->pre);
+	  tmp = gfc_deallocate_alloc_comp (ts.derived, tmp, 0);
 	  if (r_is_var)
 	    tmp = build3_v (COND_EXPR, cond, build_empty_stmt (), tmp);
-	  gfc_add_expr_to_block (&lse->pre, tmp);
+	  gfc_add_expr_to_block (&lse->post, tmp);
 	}
 
-      if (r_is_var)
-	{
-	  gfc_add_block_to_block (&block, &lse->pre);
-	  gfc_add_block_to_block (&block, &rse->pre);
-	}
-      else
-	{
-	  gfc_add_block_to_block (&block, &rse->pre);
-	  gfc_add_block_to_block (&block, &lse->pre);
-	}
+      gfc_add_block_to_block (&block, &rse->pre);
+      gfc_add_block_to_block (&block, &lse->pre);
 
       gfc_add_modify_expr (&block, lse->expr,
 			   fold_convert (TREE_TYPE (lse->expr), rse->expr));
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index c8f444a91a1..8f81053e5de 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2007-07-28  Paul Thomas  <pault@gcc.gnu.org>
+
+	PR fortran/32880
+	* gfortran.dg/alloc_comp_assign_6.f90: New tests.
+
 2007-07-28  Rask Ingemann Lambertsen  <rask@sygehus.dk>
 
 	PR testsuite/32471
diff --git a/gcc/testsuite/gfortran.dg/alloc_comp_assign_6.f90 b/gcc/testsuite/gfortran.dg/alloc_comp_assign_6.f90
new file mode 100644
index 00000000000..4e8edc22872
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/alloc_comp_assign_6.f90
@@ -0,0 +1,55 @@
+! { dg-do run }
+! Tests the fix for pr32880, in which 'res' was deallocated
+! before it could be used in the concatenation.
+! Adapted from vst28.f95, in Lawrie Schonfeld's iso_varying_string
+! testsuite, by Tobias Burnus.
+!
+module iso_varying_string
+  type varying_string
+     character(LEN=1), dimension(:), allocatable :: chars
+  end type varying_string
+  interface assignment(=)
+     module procedure op_assign_VS_CH
+  end interface assignment(=)
+  interface operator(//)
+     module procedure op_concat_VS_CH
+  end interface operator(//)
+contains
+  elemental subroutine op_assign_VS_CH (var, exp)
+    type(varying_string), intent(out) :: var
+    character(LEN=*), intent(in)      :: exp
+    integer                      :: length
+    integer                      :: i_char
+    length = len(exp)
+    allocate(var%chars(length))
+    forall(i_char = 1:length)
+       var%chars(i_char) = exp(i_char:i_char)
+    end forall
+  end subroutine op_assign_VS_CH
+  elemental function op_concat_VS_CH (string_a, string_b) result (concat_string)
+    type(varying_string), intent(in) :: string_a
+    character(LEN=*), intent(in)     :: string_b
+    type(varying_string)             :: concat_string
+    len_string_a = size(string_a%chars)
+    allocate(concat_string%chars(len_string_a+len(string_b)))
+    if (len_string_a >0) &
+       concat_string%chars(:len_string_a) = string_a%chars
+    if (len (string_b) > 0) &
+       concat_string%chars(len_string_a+1:) = string_b
+  end function op_concat_VS_CH
+end module iso_varying_string
+
+program VST28
+  use iso_varying_string
+  character(len=10) :: char_a
+  type(VARYING_STRING) :: res
+  char_a = "abcdefghij"
+  res = char_a(5:5)
+  res = res//char_a(6:6)
+  if(size(res%chars) /= 2 .or. any(res%chars /= ['e','f'])) then
+    write(*,*) 'ERROR: should be ef, got: ', res%chars, size(res%chars)
+    call abort ()
+  end if
+end program VST28
+
+! { dg-final { cleanup-modules "iso_varying_string" } }