https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122847
Bug ID: 122847
Summary: [16 Regression] ICE non-trivial conversion in
‘ssa_name’
Product: gcc
Version: 16.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: kacper.slominski72 at gmail dot com
Target Milestone: ---
Originally found while compiling Linux 6.17.9 (original preprocessed file and
error attached). Fails at all optimization levels above -O0.
Reduced test case:
struct {
char x[6];
} *a, b;
int c;
int d() {
char *p = a ? a->x : b.x;
char e = *p;
if (c)
return *(short *)p & e;
return 0;
}
Built with the following flags:
$ gcc min.c -c -o min.o -fno-strict-aliasing -O1
I've modified the reduced code a bit to get rid of UB and make it not a no-op
(original reduction did had just a `*(short *)p & *(unsigned int *)0;`
expression in the consequent.
Fails with:
min.c: In function ‘d’:
min.c:14:1: error: non-trivial conversion in ‘ssa_name’
14 | }
| ^
short int
char
_4 = e_12;
during GIMPLE pass: phiprop
min.c:14:1: internal compiler error: verify_gimple failed
0x55ab2f465764 internal_error(char const*, ...)
/usr/src/debug/sys-devel/gcc-16.0.9999/gcc-16.0.9999/gcc/diagnostic-global-context.cc:787
0x55ab2dc5cf0d verify_gimple_in_cfg(function*, bool, bool)
/usr/src/debug/sys-devel/gcc-16.0.9999/gcc-16.0.9999/gcc/tree-cfg.cc:5599
0x55ab2da49bfd execute_function_todo
/usr/src/debug/sys-devel/gcc-16.0.9999/gcc-16.0.9999/gcc/passes.cc:2097
0x55ab2da4a03e do_per_function
/usr/src/debug/sys-devel/gcc-16.0.9999/gcc-16.0.9999/gcc/passes.cc:1696
0x55ab2da4a03e execute_todo
/usr/src/debug/sys-devel/gcc-16.0.9999/gcc-16.0.9999/gcc/passes.cc:2149
gcc version:
gcc (Gentoo 16.0.9999 p, commit d93ac8e926116356695925acea88cb496d9ddaa8)
16.0.0 20251125 (experimental) 6931ba63fc0fc4b9def5d6c4d13a3e29682448b0
