https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64921
Uroš Bizjak <ubizjak at gmail dot com> changed:
What |Removed |Added
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CC| |rguenther at suse dot de
--- Comment #18 from Uroš Bizjak <ubizjak at gmail dot com> ---
(In reply to Uroš Bizjak from comment #17)
> (In reply to Mat Cross from comment #14)
> > For the record, perhaps it is of interest for me to note that we are running
> > into this (cf. PR64230 comment 9) on code like
> >
> > Program test
> > Implicit None
> > Type :: t1
> > Integer, Allocatable :: i
> > End Type
> > Type :: t2
> > Integer, Allocatable :: i
> > End Type
> > Type, Extends (t1) :: t3
> > Type (t2) :: j
> > End Type
> > Type, Extends (t3) :: t4
> > Integer, Allocatable :: k
> > End Type
> > Call s
> > Print *, 'ok'
> > Contains
> > Subroutine s
> > Class (t1), Allocatable :: x
> > Allocate (t4 :: x)
> > End Subroutine
> > End Program
> >
> > Since the crash is in bad compiler-generated finalization code (since 4.9),
> > and given that (if I recall correctly) gfortran is using the Fortran 2008
> > semantics for entities declared in a main program being implicitly saved,
> > this is why removing the Deallocate (in the comment 12 example) works - the
> > finalizer is never called then.
>
> No wonder this test crashes. Tree-optimizers (-O2) on x86_64 produce:
[...]
I was able to trace dumps down to _.fre2 tree dump, where we have:
<bb 12>:
# idx_104 = PHI <0(11), idx_122(16)>
offset_115 = 0;
ptr2_119 = (struct t3 *) offset_115;
_120 = &ptr2_119->j;
This can't be right, we have a dereference from zero. If the frontend produced
correct code, then tree-optimization passes made a mess here.
CC Richi.
