https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80119
Bug ID: 80119
Summary: -Wmaybe-uninitialized wrongly flags the body of a
short-circuited if-clause
Product: gcc
Version: 6.3.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: julian.pfeifle at upc dot edu
Target Milestone: ---
Consider
#include <type_traits>
template <bool b>
void failing_function(std::integral_constant<bool, b>)
{
int i;
if (b && (i=4)) {
++i;
}
}
int main (void)
{
failing_function(std::false_type());
}
Compiling with -Wall gives
test.cc: In function `void failing_function(std::integral_constant<bool, __v>)
[with bool b = false]`:
test.cc:8:7: error: `i` may be used uninitialized in this function
[-Werror=maybe-uninitialized]
++i;
^~
even though b is false, for which reason the body of the if-clause shouldn't
even be considered.
Calling failing_function(std::true_type()) compiles, as expected.
The `i=4` originally was a more complicated function call.
The error is important because it precludes compiling with -Werror.
gcc versions up to 6.1.0 handled this fine, I don't know about 6.2.*.
