https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95768
Bug ID: 95768
Summary: -march=sandybridge -O2 -Wall crashes as 'during GIMPLE
pass: uninit ... Segmentation fault'
Product: gcc
Version: 11.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: slyfox at inbox dot ru
Target Milestone: ---
SIGSEGV initially observed on qtcore-5.14.2 package.
Here is the minimal(ish) reproducer:
// $ cat bug.cc
extern "C" void *malloc(unsigned long);
class a {
public:
enum c { Array };
};
class d {
public:
static int e(int);
};
class f {
public:
int g;
void operator=(int) { d::e(g); }
};
template < typename, int, int > using h = f;
template < int i, int j > using k = h< int, i, j >;
template < int i, int j > using l = h< int, i, j >;
class m {
public:
k< 0, 1 > is_object;
k< 1, 1 > length;
};
class n {
public:
m *o() { return (m *)this; }
};
class p {
public:
enum {} alloc;
n *header;
p(a::c) {
header = (n *)malloc(alloc);
m b = *header->o();
b.length = 0;
}
};
void detach2() { p(a::Array); }
LANG=C /usr/bin/x86_64-pc-linux-gnu-g++ -march=sandybridge -O2 -Wall -c bug.cc
-o bug.o
bug.cc: In constructor 'p::p(a::c)':
bug.cc:32:26: warning: '*<unknown>.p::alloc' is used uninitialized
[-Wuninitialized]
32 | header = (n *)malloc(alloc);
| ^~~~~
'
during GIMPLE pass: uninit
In function 'void detach2()':
Segmentation fault
37 | void detach2() { p(a::Array); }
| ^~~~~~~
0xa9c91f crash_signal
../../gcc-11.0.0_pre9999/gcc/toplev.c:328
0x7f2dc77d2c3f ???
/usr/src/debug/sys-libs/glibc-2.31-r5/glibc-2.31/signal/../sysdeps/unix/sysv/linux/x86_64/sigaction.c:0
0xce7494 location_wrapper_p(tree_node const*)
../../gcc-11.0.0_pre9999/gcc/tree.h:3999
0xce7494 tree_strip_any_location_wrapper(tree_node*)
../../gcc-11.0.0_pre9999/gcc/tree.h:4011
0xce7494 integer_onep(tree_node const*)
../../gcc-11.0.0_pre9999/gcc/tree.c:2573
0x4e0ee3 dump_expr
../../gcc-11.0.0_pre9999/gcc/cp/error.c:2386
0x4e3640 expr_to_string(tree_node*)
../../gcc-11.0.0_pre9999/gcc/cp/error.c:3109
0x4e3cfc cp_printer
../../gcc-11.0.0_pre9999/gcc/cp/error.c:4264
0x13e0646 pp_format(pretty_printer*, text_info*)
../../gcc-11.0.0_pre9999/gcc/pretty-print.c:1475
0x13d48e2 diagnostic_report_diagnostic(diagnostic_context*, diagnostic_info*)
../../gcc-11.0.0_pre9999/gcc/diagnostic.c:1159
0x13d683a diagnostic_impl
../../gcc-11.0.0_pre9999/gcc/diagnostic.c:1309
0x13d683a warning_at(unsigned int, int, char const*, ...)
../../gcc-11.0.0_pre9999/gcc/diagnostic.c:1446
0xc5e7ed maybe_warn_operand
../../gcc-11.0.0_pre9999/gcc/tree-ssa-uninit.c:418
0xc619e9 warn_uninitialized_vars
../../gcc-11.0.0_pre9999/gcc/tree-ssa-uninit.c:640
0xc66016 execute
../../gcc-11.0.0_pre9999/gcc/tree-ssa-uninit.c:2936
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <https://bugs.gentoo.org/> for instructions.
