[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 jakub at gcc dot gnu.org 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 #13 from Jakub Jelinek jakub at gcc dot gnu.org 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=gccview=revrev=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 Jakub Jelinek jakub at gcc dot gnu.org changed: What|Removed |Added Status|ASSIGNED|RESOLVED Resolution||FIXED --- Comment #14 from Jakub Jelinek jakub at gcc dot gnu.org 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
Jakub Jelinek jakub at gcc dot gnu.org changed:
What|Removed |Added
CC||jakub at gcc dot gnu.org
--- Comment #3 from Jakub Jelinek jakub at gcc dot gnu.org 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
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43808 --- Comment #4 from Richard Guenther rguenth at gcc dot gnu.org 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
--- Comment #5 from Jakub Jelinek jakub at gcc dot gnu.org 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] var_decl
0x7ff967060140 x) [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:
var_decl 0x71ac9140 D.1548
type record_type 0x71cd69d8 a asm_written BLK
size integer_cst 0x71cccb40 constant 384
unit size integer_cst 0x71cc7dc0 constant 48
align 64 symtab -238246416 alias set 6 canonical type 0x71cd69d8
fields field_decl 0x71cd85f0 i type record_type 0x71cd6dc8
array1_integer(kind=4)
BLK file c.f90 line 1 col 0 size integer_cst 0x71cccb40 384
unit size integer_cst 0x71cc7dc0 48
align 64 offset_align 128
offset integer_cst 0x71bdb438 constant 0
bit offset integer_cst 0x71bdbb40 constant 0 context
record_type 0x71cd69d8 a
pointer_to_this pointer_type 0x71abf690 chain type_decl
0x71abd170 D.1516
used ignored BLK file c.f90 line 5 col 0 size integer_cst 0x71cccb40
384 unit size integer_cst 0x71cc7dc0 48
align 64 context function_decl 0x71cd7100 MAIN__
(mem/s/c:BLK (plus:DI (reg/f:DI 54 virtual-stack-vars)
(const_int -384 [0xfe80])) [6 D.1548+0 S48 A64]) chain
var_decl 0x71ac1aa0 a.3
.
In the MEM[(struct a[2] *)D.1692_63][0] = x[0]; stmt LHS is:
array_ref 0x71c14630
type record_type 0x71cd69d8 a asm_written BLK
size integer_cst 0x71cccb40 constant 384
unit size integer_cst 0x71cc7dc0 constant 48
align 64 symtab -238246416 alias set 6 canonical type 0x71cd69d8
fields field_decl 0x71cd85f0 i type record_type 0x71cd6dc8
array1_integer(kind=4)
BLK file c.f90 line 1 col 0 size integer_cst 0x71cccb40 384
unit size integer_cst 0x71cc7dc0 48
align 64 offset_align 128
offset integer_cst 0x71bdb438 constant 0
bit offset integer_cst 0x71bdbb40 constant 0 context
record_type 0x71cd69d8 a
pointer_to_this pointer_type 0x71abf690 chain type_decl
0x71abd170 D.1516
arg 0 mem_ref 0x71adca80
type array_type 0x71ac63f0 type record_type 0x71cd69d8 a
BLK
size integer_cst 0x71cccbb8 constant 768
unit size integer_cst 0x71cc7e38 constant 96
align 64 symtab 0 alias set 6 canonical type 0x71ac63f0 domain
integer_type 0x71abf888
pointer_to_this pointer_type
[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 jakub at gcc dot gnu.org 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 #7 from Richard Guenther rguenth at gcc dot gnu.org 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 Richard Guenther rguenth at gcc dot gnu.org 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 rguenth at gcc dot gnu.org 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 #9 from Jakub Jelinek jakub at gcc dot gnu.org 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 Jakub Jelinek jakub at gcc dot gnu.org changed: What|Removed |Added AssignedTo|rguenth at gcc dot gnu.org |jakub at gcc dot gnu.org --- Comment #10 from Jakub Jelinek jakub at gcc dot gnu.org 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 #11 from Jakub Jelinek jakub at gcc dot gnu.org 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
--- 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
