Hello,
this is about a pointer bounds remapping regression introduced at
http://gcc.gnu.org/r190641
That revision introduced support for se.descriptor_only in
gfc_conv_expr_descriptor with this hunk:
> Index: trans-array.c
> ===================================================================
> --- trans-array.c (révision 220514)
> +++ trans-array.c (copie de travail)
> @@ -6574,7 +6574,7 @@ gfc_conv_expr_descriptor (gfc_se *se, gfc_expr *ex
> /* Create a new descriptor if the array doesn't have one. */
> full = 0;
> }
> - else if (info->ref->u.ar.type == AR_FULL)
> + else if (info->ref->u.ar.type == AR_FULL || se->descriptor_only)
> full = 1;
> else if (se->direct_byref)
> full = 0;
The problem comes from gfc_trans_pointer_assign, which uses several
times the same gfc_se struct, the first time with descriptor_only set,
the other times without clearing it.
This was not a problem before the above change, because the flag wasn't
looked at.
After the change however, one should make sure that descriptor_only is
not inherited from a previous use.
The fix proposed clears the flag upon reuse, which should match exactly
the original behaviour, making it rather safe, and suitable also for the
branches.
I have to admit that I'm not completely satisfied with it however.
I would prefer no GFC_SE reuse at all, namely collect every piece of
code in a separate struct, and merge them later explicitly into a block.
Alas, the code is not exactly straightforward to my eyes, and my
attempt in that direction to sneak some orthogonality in that madness
failed.
Anyway, regression tested on x86_64-linux, OK for trunk/4.9/4.8 ?
Mikael
2015-02-09 Mikael Morin <[email protected]>
PR fortran/61138
* trans-expr.c (gfc_trans_pointer_assignment): Clear DESCRIPTOR_ONLY
field before reusing LSE.
2015-02-09 Mikael Morin <[email protected]>
PR fortran/61138
gfortran.dg/pointer_remapping_9.f90: New.
Index: trans-expr.c
===================================================================
--- trans-expr.c (révision 220514)
+++ trans-expr.c (copie de travail)
@@ -7339,6 +7339,7 @@ gfc_trans_pointer_assignment (gfc_expr * expr1, gf
bound, bound, 0,
GFC_ARRAY_POINTER_CONT, false);
tmp = gfc_create_var (tmp, "ptrtemp");
+ lse.descriptor_only = 0;
lse.expr = tmp;
lse.direct_byref = 1;
gfc_conv_expr_descriptor (&lse, expr2);
@@ -7354,6 +7355,7 @@ gfc_trans_pointer_assignment (gfc_expr * expr1, gf
else if (expr2->expr_type == EXPR_VARIABLE)
{
/* Assign directly to the LHS's descriptor. */
+ lse.descriptor_only = 0;
lse.direct_byref = 1;
gfc_conv_expr_descriptor (&lse, expr2);
strlen_rhs = lse.string_length;
@@ -7405,6 +7407,7 @@ gfc_trans_pointer_assignment (gfc_expr * expr1, gf
/* Assign to a temporary descriptor and then copy that
temporary to the pointer. */
tmp = gfc_create_var (TREE_TYPE (desc), "ptrtemp");
+ lse.descriptor_only = 0;
lse.expr = tmp;
lse.direct_byref = 1;
gfc_conv_expr_descriptor (&lse, expr2);
! { dg-do run }
!
! PR fortran/61138
! Wrong code with pointer-bounds remapping
!
! Contributed by Tobias Burnus <[email protected]>
implicit none
integer, target :: tgt(10)
integer, target, allocatable :: tgt2(:)
integer, pointer :: ptr(:)
tgt = [1,2,3,4,5,6,7,8,9,10]
tgt2 = [1,2,3,4,5,6,7,8,9,10]
ptr(-5:) => tgt(5:) ! Okay
if (size(ptr) /= 6 .or. lbound(ptr,1) /= -5) call abort()
if (any (ptr /= [5,6,7,8,9,10])) call abort()
ptr(-5:) => tgt2(5:) ! wrongly associates the whole array
print '(*(i4))', size(ptr), lbound(ptr)
print '(*(i4))', ptr
if (size(ptr) /= 6 .or. lbound(ptr,1) /= -5) call abort()
if (any (ptr /= [5,6,7,8,9,10])) call abort()
end
