[Bug target/43808] [4.6 Regression] -fipa-reference -fschedule-insns -fstrict-aliasing causes two gfortran check failures
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43808 Jakub Jelinek changed: What|Removed |Added Status|ASSIGNED|RESOLVED Resolution||FIXED --- Comment #14 from Jakub Jelinek 2010-11-09 19:32:30 UTC --- Fixed.
[Bug target/43808] [4.6 Regression] -fipa-reference -fschedule-insns -fstrict-aliasing causes two gfortran check failures
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43808 --- Comment #13 from Jakub Jelinek 2010-11-09 19:31:48 UTC --- Author: jakub Date: Tue Nov 9 19:31:45 2010 New Revision: 166509 URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=166509 Log: PR target/43808 * cfgexpand.c (partition_stack_vars): Call update_alias_info_with_stack_vars unconditionally. (update_alias_info_with_stack_vars): Allow unused unreferenced vars when not optimizing. * gfortran.dg/pr43808.f90: New test. Added: trunk/gcc/testsuite/gfortran.dg/pr43808.f90 Modified: trunk/gcc/ChangeLog trunk/gcc/cfgexpand.c trunk/gcc/testsuite/ChangeLog
[Bug target/43808] [4.6 Regression] -fipa-reference -fschedule-insns -fstrict-aliasing causes two gfortran check failures
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43808
--- Comment #12 from Jakub Jelinek 2010-11-09
12:47:56 UTC ---
The first patch bootstrapped/regtested fine on both x86_64-linux and
i686-linux, the second one caused a couple of regressions on x86_64-linux (and
worked fine on i686-linux):
FAIL: gcc.target/x86_64/abi/test_3_element_struct_and_unions.c compilation,
-O0 (internal compiler error)
UNRESOLVED: gcc.target/x86_64/abi/test_3_element_struct_and_unions.c execution,
-O0
FAIL: gcc.target/x86_64/abi/test_basic_array_size_and_align.c compilation, -O0
(internal compiler error)
UNRESOLVED: gcc.target/x86_64/abi/test_basic_array_size_and_align.c execution,
-O0
FAIL: gnat.dg/gen_disp.adb (test for excess errors)
FAIL: gnat.dg/specs/private_with.ads (test for excess errors)
All of these are ICEs in update_alias_info_with_stack_vars, short testcase on
x86_64-linux is:
int
main (void)
{
{
struct S1 { long double t1; long double t2; float t3; } s1;
}
{
struct S2 { long double t1; long double t2; double t3; } s2;
}
}
The ICE is in:
/* We should never end up partitioning SSA names (though they
may end up on the stack). Neither should we allocate stack
space to something that is unused and thus unreferenced. */
gcc_assert (DECL_P (decl)
&& referenced_var_lookup (DECL_UID (decl)));
decl is s1 (VAR_DECL), but referenced_var_lookup returns NULL on it.
Wonder if we just shouldn't add && optimize into the assert, or whether it is
really a problem if a non-referenced var makes it in.
[Bug target/43808] [4.6 Regression] -fipa-reference -fschedule-insns -fstrict-aliasing causes two gfortran check failures
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43808 --- Comment #11 from Jakub Jelinek 2010-11-08 16:39:39 UTC --- Created attachment 22329 --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=22329 gcc46-pr43808-2.patch Another possible fix (also untested).
[Bug target/43808] [4.6 Regression] -fipa-reference -fschedule-insns -fstrict-aliasing causes two gfortran check failures
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43808 Jakub Jelinek changed: What|Removed |Added AssignedTo|rguenth at gcc dot gnu.org |jakub at gcc dot gnu.org --- Comment #10 from Jakub Jelinek 2010-11-08 16:38:55 UTC --- Created attachment 22328 --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=22328 gcc46-pr43808-1.patch One possible fix (so far untested).
[Bug target/43808] [4.6 Regression] -fipa-reference -fschedule-insns -fstrict-aliasing causes two gfortran check failures
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43808 --- Comment #9 from Jakub Jelinek 2010-11-08 15:38:21 UTC --- Ah, if (optimize) update_alias_info_with_stack_vars (); explains that. Guess it should be if (optimize || ...). if (optimize || flag_strict_aliasing) would work for this testcase, but not sure if things still wouldn't break for -O0 -fschedule-insns or similar.
[Bug target/43808] [4.6 Regression] -fipa-reference -fschedule-insns -fstrict-aliasing causes two gfortran check failures
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43808 Richard Guenther changed: What|Removed |Added Status|NEW |ASSIGNED AssignedTo|unassigned at gcc dot |rguenth at gcc dot gnu.org |gnu.org | --- Comment #8 from Richard Guenther 2010-11-08 15:35:38 UTC --- I will still have a look.
[Bug target/43808] [4.6 Regression] -fipa-reference -fschedule-insns -fstrict-aliasing causes two gfortran check failures
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43808
--- Comment #7 from Richard Guenther 2010-11-08
15:32:03 UTC ---
(In reply to comment #6)
> Indeed, for
> x:
> (mem/s:DI (reg/f:DI 117 [ D.1692 ]) [6 MEM[(struct a[2] *)D.1692_63]+0 S8
> A64])
> mem:
> (mem/s/f/c:DI (plus:DI (reg/f:DI 20 frame)
> (const_int -384 [0xfe80])) [3 D.1548.i.data+0 S8 A64])
> rtx_refs_may_alias_p (x, mem, 0)
> returns 0.
> indirect_ref_may_alias_decl_p is called with base1 the MEM_REF and base2
> VAR_DECL D.1548.
>
> And the problem is that may_be_aliased is false for D.1548. Sure, it doesn't
> have address taken. But as expansion decided to share its slot together with
> other variables and those are may_be_aliased, this of course breaks.
>
> I wonder whether expansion shouldn't somehow make sure that if at least one
> var
> in the partition is may_be_aliased, all of them are. Be it by not merging
> vars
> that have different may_be_aliased, or by say marking the non-addressable vars
> TREE_ADDRESSABLE if anything in the partition is addressable.
>
> Richard?
We do this already, see cfgexpand.c:add_partitioned_vars_to_ptset and
update_alias_info_with_stack_vars and alias.c:ao_ref_from_mem:
/* If this is a reference based on a partitioned decl replace the
base with an INDIRECT_REF of the pointer representative we
created during stack slot partitioning. */
if (TREE_CODE (base) == VAR_DECL
&& ! TREE_STATIC (base)
&& cfun->gimple_df->decls_to_pointers != NULL)
{
void *namep;
namep = pointer_map_contains (cfun->gimple_df->decls_to_pointers, base);
if (namep)
ref->base = build_simple_mem_ref (*(tree *)namep);
}
and we try to handle this particular case in update_alias_info_with_stack_vars:
/* Make all points-to sets that contain one member of a partition
contain all members of the partition. */
if (decls_to_partitions)
{
unsigned i;
struct pointer_set_t *visited = pointer_set_create ();
bitmap temp = BITMAP_ALLOC (NULL);
for (i = 1; i < num_ssa_names; i++)
{
...
So you say that for some reason this doesn't work.
[Bug target/43808] [4.6 Regression] -fipa-reference -fschedule-insns -fstrict-aliasing causes two gfortran check failures
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43808 --- Comment #6 from Jakub Jelinek 2010-11-08 15:21:41 UTC --- Indeed, for x: (mem/s:DI (reg/f:DI 117 [ D.1692 ]) [6 MEM[(struct a[2] *)D.1692_63]+0 S8 A64]) mem: (mem/s/f/c:DI (plus:DI (reg/f:DI 20 frame) (const_int -384 [0xfe80])) [3 D.1548.i.data+0 S8 A64]) rtx_refs_may_alias_p (x, mem, 0) returns 0. indirect_ref_may_alias_decl_p is called with base1 the MEM_REF and base2 VAR_DECL D.1548. And the problem is that may_be_aliased is false for D.1548. Sure, it doesn't have address taken. But as expansion decided to share its slot together with other variables and those are may_be_aliased, this of course breaks. I wonder whether expansion shouldn't somehow make sure that if at least one var in the partition is may_be_aliased, all of them are. Be it by not merging vars that have different may_be_aliased, or by say marking the non-addressable vars TREE_ADDRESSABLE if anything in the partition is addressable. Richard?
[Bug target/43808] [4.6 Regression] -fipa-reference -fschedule-insns -fstrict-aliasing causes two gfortran check failures
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43808
--- Comment #5 from Jakub Jelinek 2010-11-08
14:39:51 UTC ---
The problem seems to be that on the c.f90:
...
D.1548.i.data = 0B;
atmp.7.dtype = 3113;
atmp.7.dim[0].stride = 1;
atmp.7.dim[0].lbound = 0;
atmp.7.dim[0].ubound = 1;
D.1691_62 = (void * restrict) &A.8[0];
atmp.7.data = D.1691_62;
atmp.7.offset = 0;
D.1692_63 = atmp.7.data;
MEM[(struct a[2] *)D.1692_63][0] = x[0];
D.1693_64 = atmp.7.data;
MEM[(struct a[2] *)D.1693_64][1] = x[1];
Partition 10: size 96 align 16
A.8, offset 0
A.20, offset 0
a.0, offset 0
D.1548, offset 0
(thus D.1548 and A.8 share stack slot) and we have in *.asmcons:
// This is D.1548.i.data = 0B;
(insn 250 249 251 18 (set (mem/s/f/c:DI (plus:DI (reg/f:DI 20 frame)
(const_int -384 [0xfe80])) [3 D.1548.i.data+0 S8
A64])
(const_int 0 [0])) c.f90:5 62 {*movdi_internal_rex64}
(nil))
...
// This is D.1691_62 = (void * restrict) &A.8[0];
(insn 255 254 256 18 (parallel [
(set (reg/f:DI 116 [ D.1691 ])
(plus:DI (reg/f:DI 20 frame)
(const_int -384 [0xfe80])))
(clobber (reg:CC 17 flags))
]) c.f90:6 253 {*adddi_1}
(nil))
// This is atmp.7.data = D.1691_62;
(insn 256 255 257 18 (set (mem/s/f/c:DI (plus:DI (reg/f:DI 20 frame)
(const_int -192 [0xff40])) [3 atmp.7.data+0 S8
A64])
(reg/f:DI 116 [ D.1691 ])) c.f90:6 62 {*movdi_internal_rex64}
(nil))
...
// This is D.1692_63 = atmp.7.data;
(insn 258 257 260 18 (set (reg/f:DI 117 [ D.1692 ])
(mem/s/f/c:DI (plus:DI (reg/f:DI 20 frame)
(const_int -192 [0xff40])) [3 atmp.7.data+0 S8
A64])) c.f90:6 62 {*movdi_internal_rex64}
(nil))
// These two are start of MEM[(struct a[2] *)D.1692_63][0] = x[0];
(insn 260 258 261 18 (set (reg:DI 332)
(mem/s:DI (symbol_ref:DI ("x.1518") [flags 0x2] ) [6 x+0 S8 A256])) c.f90:6 62 {*movdi_internal_rex64}
(nil))
(insn 261 260 262 18 (set (mem/s:DI (reg/f:DI 117 [ D.1692 ]) [6 MEM[(struct
a[2] *)D.1692_63]+0 S8 A64])
(reg:DI 332)) c.f90:6 62 {*movdi_internal_rex64}
(nil))
Now sched1 unfortunately schedules insn 250 after insn 261 (and whole bunch of
other insns) and as D.1548 and A.8 share stack space, this means overwriting
first 8 bytes in A.8 with NULL.
This all is with current trunk, ./f951 -quiet -fdump-tree-optimized -g
-fipa-reference -fschedule-insns -fno-schedule-insns2 -fstrict-aliasing
-fverbose-asm c.f90 on x86_64-linux.
D.1548 is:
unit size
align 64 symtab -238246416 alias set 6 canonical type 0x71cd69d8
fields
BLK file c.f90 line 1 col 0 size
unit size
align 64 offset_align 128
offset
bit offset context
>
pointer_to_this chain >
used ignored BLK file c.f90 line 5 col 0 size unit size
align 64 context
(mem/s/c:BLK (plus:DI (reg/f:DI 54 virtual-stack-vars)
(const_int -384 [0xfe80])) [6 D.1548+0 S48 A64]) chain
>
.
In the MEM[(struct a[2] *)D.1692_63][0] = x[0]; stmt LHS is:
unit size
align 64 symtab -238246416 alias set 6 canonical type 0x71cd69d8
fields
BLK file c.f90 line 1 col 0 size
unit size
align 64 offset_align 128
offset
bit offset context
>
pointer_to_this chain >
arg 0
BLK
size
unit size
align 64 symtab 0 alias set 6 canonical type 0x71ac63f0 domain
pointer_to_this >
arg 0
visited var def_stmt D.1692_63 =
atmp.7.data;
version 63>
arg 1
c.f90:6:0>
arg 1 constant 0>
c.f90:6:0>
and the type of MEM_REF's arg1 is:
unit size
align 64 symtab -238246416 alias set 6 canonical type
0x71cd69d8 fields
pointer_to_this chain >
BLK
size
unit size
align 64 symtab 0 alias set 6 canonical type 0x71ac63f0
domain
public DI
size
unit size
align 64 symtab 0 alias set -1 canonical type 0x71abf888
precision 64 min max >
pointer_to_this >
public unsigned restrict DI size unit size
align 64 symtab 0 alias set -1 canonical type 0x71ac6540>
So alias set 6 for the aggregate copy is fine and so is 3 for the void * type
(which is part of array_descriptor1 aggregate, which is part of struct a).
So it must be the alias oracle saying these two can't alias, perhaps related
somehow to the restrict or something. Richard, can you have a look at this?
[Bug target/43808] [4.6 Regression] -fipa-reference -fschedule-insns -fstrict-aliasing causes two gfortran check failures
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43808 --- Comment #4 from Richard Guenther 2010-11-08 11:27:33 UTC --- As usual this might be as well a type-merging problem in the Frontend.
[Bug target/43808] [4.6 Regression] -fipa-reference -fschedule-insns -fstrict-aliasing causes two gfortran check failures
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43808
Jakub Jelinek changed:
What|Removed |Added
CC||jakub at gcc dot gnu.org
--- Comment #3 from Jakub Jelinek 2010-11-08
11:11:56 UTC ---
Smaller testcase:
b.f90:
module pr43808
type :: a
integer, allocatable :: i(:)
end type a
type :: b
type (a), allocatable :: at(:)
end type b
contains
subroutine foo(y)
type(b) :: y(2)
forall (j=1:2,k=1:4, y(1)%at(j)%i(k) .ne. y(2)%at(j)%i(k)) &
y(1)%at(j)%i(k) = 999
end subroutine foo
end module pr43808
c.f90:
use pr43808
type(a) :: x(2)
type(b) :: y(2)
x(1) = a((/1,2,3,4/))
x(2) = a((/1,2,3,4/)+10)
y(1) = b((/x(1),x(2)/))
y(2) = b((/x(1),x(2)/))
call foo(y)
end
./f951 -quiet -g b.f90; ./f951 -quiet -g -fipa-reference -fschedule-insns
-fno-schedule-insns2 -fstrict-aliasing -fverbose-asm c.f90; gfortran -o b{,.s}
c.s; ./b; echo $?
Segmentation fault (core dumped)
139
[Bug target/43808] [4.6 Regression] -fipa-reference -fschedule-insns -fstrict-aliasing causes two gfortran check failures
--- Comment #2 from rguenth at gcc dot gnu dot org 2010-09-02 10:41 --- This looks like a genuine RTL alias problem, ipa-reference just causes x, y and z to be marked as not aliased. -- rguenth at gcc dot gnu dot org changed: What|Removed |Added Keywords||alias Priority|P3 |P1 Last reconfirmed|2010-07-23 11:47:07 |2010-09-02 10:41:30 date|| http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43808
[Bug target/43808] [4.6 Regression] -fipa-reference -fschedule-insns -fstrict-aliasing causes two gfortran check failures
--- Comment #1 from rguenth at gcc dot gnu dot org 2010-07-23 11:47 --- Confirmed. -- rguenth at gcc dot gnu dot org changed: What|Removed |Added Status|UNCONFIRMED |NEW Ever Confirmed|0 |1 Last reconfirmed|-00-00 00:00:00 |2010-07-23 11:47:07 date|| http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43808
[Bug target/43808] [4.6 Regression] -fipa-reference -fschedule-insns -fstrict-aliasing causes two gfortran check failures
-- rguenth at gcc dot gnu dot org changed: What|Removed |Added Keywords||wrong-code Target Milestone|--- |4.6.0 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43808
