https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105971
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Assignee|unassigned at gcc dot gnu.org |rguenth at gcc dot
gnu.org
Last reconfirmed| |2022-06-15
Priority|P3 |P2
Ever confirmed|0 |1
Status|UNCONFIRMED |ASSIGNED
Keywords|needs-bisection |
--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
Confirmed.
#1 0x0000000002d39e66 in bitmap_check_index (map=0x44062b0, index=-1)
at /space/rguenther/src/gcc/gcc/sbitmap.h:104
104 gcc_checking_assert (index >= 0);
get_byte_range returns true but a size of zero, it seems to be constrainted
on "COPY inside REF" but we have
(gdb) p *use_ref
$3 = {ref = <realpart_expr 0x7ffff6a0f920>,
base = <function_decl 0x7ffff6a00200 a>,
offset = {<poly_int_pod<1, long>> = {coeffs = {0}}, <No data fields>},
size = {<poly_int_pod<1, long>> = {coeffs = {32}}, <No data fields>},
max_size = {<poly_int_pod<1, long>> = {coeffs = {32}}, <No data fields>},
ref_alias_set = -1, base_alias_set = -1, volatile_p = false}
(gdb) p *ref
$4 = {ref = <imagpart_expr 0x7ffff6a0f9a0>,
base = <function_decl 0x7ffff6a00200 a>,
offset = {<poly_int_pod<1, long>> = {coeffs = {32}}, <No data fields>},
size = {<poly_int_pod<1, long>> = {coeffs = {32}}, <No data fields>},
max_size = {<poly_int_pod<1, long>> = {coeffs = {32}}, <No data fields>},
ref_alias_set = -1, base_alias_set = -1, volatile_p = false}
which means the refs do not overlap. We have
(gdb) p debug_gimple_stmt (use_stmt)
# VUSE <.MEM_16>
_2 = REALPART_EXPR <MEM[(complex float *)a]>;
$5 = void
(gdb) p debug_gimple_stmt (stmt)
# .MEM_21 = VDEF <.MEM_18>
IMAGPART_EXPR <MEM[(complex float *)a]> = _5;
so we expected ref_maybe_used_by_stmt_p to return false but it does not
(because we reference a FUNCTION_DECL). That's because of
/* We can end up referring to code via function and label decls.
As we likely do not properly track code aliases conservatively
bail out. */
if (TREE_CODE (base1) == FUNCTION_DECL
|| TREE_CODE (base1) == LABEL_DECL
|| TREE_CODE (base2) == FUNCTION_DECL
|| TREE_CODE (base2) == LABEL_DECL)
return true;
we can make this less restrictive for the case of two decls which is also
the case DSE is interested in here.
