https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96278
Bug ID: 96278
Summary: three-way comparison operator comparison to 0:
spurious nullptr warning
Product: gcc
Version: 10.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: gu...@henkel-wallace.org
Target Milestone: ---
Bug in g++ 10.1.0 with libstdc++
compile following program doing `g++-10 -std=c++20
-Wzero-as-null-pointer-constant`
#include <iostream>
#include <compare>
int main () {
bool result { (1 <=> 2) < 0 };
std::cout << (result ? "Yes" : "No") << std::endl;
}
produces the error:
foo.cc:5:27: warning: zero as null pointer constant
[-Wzero-as-null-pointer-constant]
Also compiler-synthesized comparisons will generate this which is especially
confusing as they can happen when calling a library function that needs the '<'
operator.
the exact version of GCC: 10.1.0
the system type: MacOS 10.15 (and Ubuntu 18.4 LTS using apt-get of gcc 10)
the options given when GCC was configured/built: (homebrew version): Configured
with: ../configure --build=x86_64-apple-darwin19
--prefix=/usr/local/Cellar/gcc/10.1.0
--libdir=/usr/local/Cellar/gcc/10.1.0/lib/gcc/10 --disable-nls
--enable-checking=release --enable-languages=c,c++,objc,obj-c++,fortran
--program-suffix=-10 --with-gmp=/usr/local/opt/gmp
--with-mpfr=/usr/local/opt/mpfr --with-mpc=/usr/local/opt/libmpc
--with-isl=/usr/local/opt/isl --with-system-zlib --with-pkgversion='Homebrew
GCC 10.1.0' --with-bugurl=https://github.com/Homebrew/homebrew-core/issues
--disable-multilib --with-native-system-header-dir=/usr/include
--with-sysroot=/Library/Developer/CommandLineTools/SDKs/MacOSX10.15.sdk
SED=/usr/bin/sed
