https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67149
Bug ID: 67149
Summary: false positive maybe-uniniialized in the presense of
cilk spawn
Product: gcc
Version: 5.1.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: kuszmaul at gmail dot com
Target Milestone: ---
The following program produces an invalid maybe-uninitialized warning on
variable z, which is initialized. There is no way for z to be used
uninitialized.
$ cat warning.cc
extern void f();
extern void h(int, int*);
void g(int m, int *a){
if (m <= 1) return;
int j = 0;
for (int k = m; k < m + 2; k++){
if(a[k]) j = (a)[k];
}
if (j) {
f();
}
int z = m +1;
_Cilk_spawn h(m+1, a);
h(z+2, a);
}
$ g++ --version
g++ (GCC) 5.1.1 20150618 (Red Hat 5.1.1-4)
Copyright (C) 2015 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
$ g++ -O3 -Wall -Werror -g -std=c++11 warning.cc -c -fcilkplus
warning.cc: In function ‘void g(int, int*)’:
warning.cc:13:9: error: ‘z’ may be used uninitialized in this function
[-Werror=maybe-uninitialized]
int z = m +1;
^
cc1plus: all warnings being treated as errors
$
