https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107310
Bug ID: 107310
Summary: "warning: control reaches end of non-void function"
with a throw under a trivially-true conditional
Product: gcc
Version: 12.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: lvoege at gmail dot com
Target Milestone: ---
Created attachment 53727
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=53727&action=edit
preprocessed test case
gcc 12 starting with revision a3e75c14 gives "warning: control reaches end of
non-void function" for the following contrived and I think minimal test case
when compiling without optimization. the preprocessed .ii file is attached for
completeness. remove any bit of it and it stops complaining.
#include <mutex>
std::mutex m;
int t;
int foo() {
std::lock_guard guard(m);
switch (t) {
case 1: return 1;
}
if (true) {
throw std::runtime_error("!");
}
}
this is on ubuntu, but a build from source does the same, as does yesterday's
trunk:
$ gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/12/lto-wrapper
OFFLOAD_TARGET_NAMES=nvptx-none:amdgcn-amdhsa
OFFLOAD_TARGET_DEFAULT=1
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu 12.2.0-3ubuntu1'
--with-bugurl=file:///usr/share/doc/gcc-12/README.Bugs
--enable-languages=c,ada,c++,go,d,fortran,objc,obj-c++,m2 --prefix=/usr
--with-gcc-major-version-only --program-suffix=-12
--program-prefix=x86_64-linux-gnu- --enable-shared --enable-linker-build-id
--libexecdir=/usr/lib --without-included-gettext --enable-threads=posix
--libdir=/usr/lib --enable-nls --enable-clocale=gnu --enable-libstdcxx-debug
--enable-libstdcxx-time=yes --with-default-libstdcxx-abi=new
--enable-gnu-unique-object --disable-vtable-verify --enable-plugin
--enable-default-pie --with-system-zlib --enable-libphobos-checking=release
--with-target-system-zlib=auto --enable-objc-gc=auto --enable-multiarch
--disable-werror --enable-cet --with-arch-32=i686 --with-abi=m64
--with-multilib-list=m32,m64,mx32 --enable-multilib --with-tune=generic
--enable-offload-targets=nvptx-none=/build/gcc-12-U8K4Qv/gcc-12-12.2.0/debian/tmp-nvptx/usr,amdgcn-amdhsa=/build/gcc-12-U8K4Qv/gcc-12-12.2.0/debian/tmp-gcn/usr
--enable-offload-defaulted --without-cuda-driver --enable-checking=release
--build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 12.2.0 (Ubuntu 12.2.0-3ubuntu1)
$ gcc -c foo3.cpp
foo3.cpp: In function ‘int foo()’:
foo3.cpp:14:1: warning: control reaches end of non-void function
[-Wreturn-type]
14 | }
| ^
