https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63906
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Summary|[5 Regression] lra_remat |[5 Regression] dse after
|mis-compiles glibc on |reload miscompiles glibc
|aarch64 |with lra_remat turned on
| |aarch64
--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
It looks like dse is removing more stores when lra_remat is enable:
(insn 538 537 2663 41 (set (mem/f:DI (plus:DI (reg/f:DI 1 x1 [581])
(const_int 16 [0x10])) [1 runp_409->next+0 S8 A128])
(const_int 0 [0])) dl-deps.c:283 42 {*movdi_aarch64}
(nil))
That is for:
newp->next = NULL;
tail->next = newp;
DSE (after reload) thinks tail->next is the same as the store to newp->next
with LRA_REMAT turned on.
**scanning insn=538
mem: (plus:DI (reg/f:DI 1 x1 [581])
(const_int 16 [0x10]))
after canon_rtx address: (plus:DI (reg/f:DI 1 x1 [581])
(const_int 16 [0x10]))
after cselib_expand address: (plus:DI (reg/f:DI 31 sp)
(const_int 16 [0x10]))
....
**scanning insn=539
mem: (plus:DI (reg/v/f:DI 2 x2 [orig:88 runp ] [88])
(const_int 16 [0x10]))
after canon_rtx address: (plus:DI (reg/v/f:DI 2 x2 [orig:88 runp ] [88])
(const_int 16 [0x10]))
after cselib_expand address: (plus:DI (reg/f:DI 31 sp)
(const_int 16 [0x10]))
after canon_rtx address: (plus:DI (reg/f:DI 31 sp)
(const_int 16 [0x10]))
varying cselib base=2:4287 offset = 16
processing cselib store [16..24)
**scanning insn=539
mem: (plus:DI (reg/v/f:DI 2 x2 [orig:88 runp ] [88])
(const_int 16 [0x10]))
after canon_rtx address: (plus:DI (reg/v/f:DI 2 x2 [orig:88 runp ] [88])
(const_int 16 [0x10]))
after cselib_expand address: (plus:DI (reg/f:DI 31 sp)
(const_int 16 [0x10]))
after canon_rtx address: (plus:DI (reg/f:DI 31 sp)
(const_int 16 [0x10]))
varying cselib base=2:4287 offset = 16
processing cselib store [16..24)
