https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102403
Bug ID: 102403
Summary: [12 Regression] ICE in in init_from_control_deps, at
gimple-predicate-analysis.cc:2364
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: middle-end
Assignee: unassigned at gcc dot gnu.org
Reporter: msebor at gcc dot gnu.org
Target Milestone: ---
As reported in
https://gcc.gnu.org/pipermail/gcc-patches/2021-September/579736.html, the
following test case reduced from s_fmaf.c triggers an ICE in the new
predicate-analysis module introduced in r12-3640.
$ cat s_fmaf.c && gcc -S -O2 -Wall -Werror s_fmaf.c
int __fmaf (void)
{
int a = 0;
int b, c, d, e, f;
int r = 0;
switch (b)
{
default:
c |= 1;
case 0:
if (c == 0)
a = 1;
switch (d) {
case 15:
f = c;
break;
case 11:
case 6:
case 4:
f = c;
case 10:
e = a;
}
if (e == 0)
f = 0;
r = f;
}
return r;
}
s_fmaf.c: In function ‘__fmaf’:
s_fmaf.c:8:3: error: ‘b’ is used uninitialized [-Werror=uninitialized]
8 | switch (b)
| ^~~~~~
s_fmaf.c:4:7: note: ‘b’ was declared here
4 | int b, c, d, e, f;
| ^
s_fmaf.c:4:13: error: ‘d’ is used uninitialized [-Werror=uninitialized]
4 | int b, c, d, e, f;
| ^
s_fmaf.c:4:10: error: ‘c’ may be used uninitialized
[-Werror=maybe-uninitialized]
4 | int b, c, d, e, f;
| ^
during GIMPLE pass: uninit
s_fmaf.c:1:5: internal compiler error: in init_from_control_deps, at
gimple-predicate-analysis.cc:2364
1 | int __fmaf (void)
| ^~~~~~
0x264d8b4 predicate::init_from_control_deps(vec<edge_def*, va_heap, vl_ptr>
const*, unsigned int)
/src/gcc/master/gcc/gimple-predicate-analysis.cc:2364
0x264c28c predicate::init_from_phi_def(gphi*)
/src/gcc/master/gcc/gimple-predicate-analysis.cc:1829
0x264c47a predicate::is_use_guarded(gimple*, basic_block_def*, gphi*, unsigned
int, hash_set<gphi*, false, default_hash_traits<gphi*> >*)
/src/gcc/master/gcc/gimple-predicate-analysis.cc:1902
0x264c5b3 predicate::is_use_guarded(gimple*, basic_block_def*, gphi*, unsigned
int)
/src/gcc/master/gcc/gimple-predicate-analysis.cc:1933
0x1672895 find_uninit_use
/src/gcc/master/gcc/tree-ssa-uninit.c:1092
0x1672b11 warn_uninitialized_phi
/src/gcc/master/gcc/tree-ssa-uninit.c:1149
0x1673090 execute_late_warn_uninitialized
/src/gcc/master/gcc/tree-ssa-uninit.c:1275
0x167310b execute
/src/gcc/master/gcc/tree-ssa-uninit.c:1288
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <https://gcc.gnu.org/bugs/> for instructions.
