https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96057
Bug ID: 96057
Summary: -Wreturn-type warning message disappears with -O1 to
-Os in unnamed namespace definition
Product: gcc
Version: 11.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: haoxintu at gmail dot com
Target Milestone: ---
Hi, all.
This small code, bug.cc, the -Wreturn-type warning disappears when add -O1 or
higher optimization option.
$cat bug.cc
namespace {
int foo() { 1 ? 0 : throw 0 ; }
}
$g++ -c -Wreturn-type -O0 bug.cc
bug.cc: In function 'int {anonymous}::foo()':
bug.cc:2:35: warning: control reaches end of non-void function [-Wreturn-type]
2 | int foo() { 1 ? 0 : throw 0 ; }
|
$g++ -c -Wreturn-type -O1 bug.cc
//emit nothing with -O1 to -Os option
While in Clang, the output of -O0 to -Os is the same. For example,
$clang++ -c -Wreturn-type -O1 bug.cc
bug.cc:2:35: warning: non-void function does not return a value [-Wreturn-type]
int foo() { 1 ? 0 : throw 0 ; }
^
1 warning generated.
$g++ -v
Using built-in specs.
COLLECT_GCC=g++
COLLECT_LTO_WRAPPER=/home/haoxin/corpus-compilers/gcc-trunk/gcc-master/build/libexec/gcc/x86_64-pc-linux-gnu/11.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../configure
--prefix=/home/haoxin/corpus-compilers/gcc-trunk/gcc-master/build/
--enable-languages=c,c++ CC=gcc CXX=g++
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 11.0.0 20200630 (experimental) (GCC)
