https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105393
Bug ID: 105393
Summary: A simple for loop becomes an infinite when -O1/2/3
used
Product: gcc
Version: 10.2.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: 364961 at mail dot ru
Target Milestone: ---
Created attachment 52884
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=52884&action=edit
the preprocessed bug's source file
The main function calls a function with a for loop inside. The called function
is declared like boolean, but in fact doesn't return any result. In this case
the for
loop becomes infinite when any optimisation used. But if:
- disable an optimisation;
- return boolean result;
- declare the function as void.
The behaviour will become correct. It looks like the bug 49218, but a little
bit
different.
build row:
g++ -O2 -std=c++11 -c main.cpp main.o
the compiler output:
main.cpp: In function ‘bool initAllBuffers()’:
aleksandr@workHost:~/work/multaleksandr@workHost:~/work/multex/
main.cpp:47:1: warning: no return statement in function returning non-void
[-Wreturn-type]
aleksandr@workHost:~/work/mulaleksandr@workHost:~/work/multex/a
47 | }
g++ -v
Using built-in specs.
COLLECT_GCC=g++
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/10/lto-wrapper
OFFLOAD_TARGET_NAMES=nvptx-none:amdgcn-amdhsa:hsa
OFFLOAD_TARGET_DEFAULT=1
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Debian 10.2.1-6'
--with-bugurl=file:///usr/share/doc/gcc-10/README.Bugs
--enable-languages=c,ada,c++,go,brig,d,fortran,objc,obj-c++,m2 --prefix=/usr
--with-gcc-major-version-only --program-suffix=-10
--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-bootstrap --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 --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-10-Km9U7s/gcc-10-10.2.1/debian/tmp-nvptx/usr,amdgcn-amdhsa=/build/gcc-10-Km9U7s/gcc-10-10.2.1/debian/tmp-gcn/usr,hsa
--without-cuda-driver --enable-checking=release --build=x86_64-linux-gnu
--host=x86_64-linux-gnu --target=x86_64-linux-gnu
--with-build-config=bootstrap-lto-lean --enable-link-mutex
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 10.2.1 20210110 (Debian 10.2.1-6)
