Package: cpp-9 Version: 9.2.1-21 Severity: normal Hi,
current gcc 9.2 cannot compile this program with -m32:
int main() {
asm volatile ("mov %%eax, %%eax\n" : : "i" ("A string"));
return 0;
}
Result is:
$ gcc -m32 test.c
test.c: In function ‘main’:
test.c:3:5: warning: asm operand 0 probably doesn’t match constraints
3 | asm volatile ("mov %%eax, %%eax\n" : : "i" ("A string"));
| ^~~
test.c:3:5: error: impossible constraint in ‘asm’
I believe that the program is valid, though. The same program compiles
on Compiler Explorer[1], it compiles with clang, and it compiles with a
vanilla gcc 9.2 compiled from upstream distributed sources. It also
compiles with Debian's gcc 9.2 without -m32.
[1] https://godbolt.org/z/f87U62
I use an up-to-date Debian sid, with this gcc:
> $ gcc -v
> Using built-in specs.
> COLLECT_GCC=gcc
> COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/9/lto-wrapper
> OFFLOAD_TARGET_NAMES=nvptx-none:hsa
> OFFLOAD_TARGET_DEFAULT=1
> Target: x86_64-linux-gnu
> Configured with: ../src/configure -v --with-pkgversion='Debian 9.2.1-21'
> --with-bugurl=file:///usr/share/doc/gcc-9/README.Bugs
> --enable-languages=c,ada,c++,go,brig,d,fortran,objc,obj-c++,gm2 --prefix=/usr
> --with-gcc-major-version-only --program-suffix=-9
> --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 --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,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
> gcc version 9.2.1 20191130 (Debian 9.2.1-21)
The vanilla gcc 9.2 that manages to compile is:
> $ /tmp/gcc/bin/gcc -v
> Using built-in specs.
> COLLECT_GCC=/tmp/gcc/bin/gcc
> COLLECT_LTO_WRAPPER=/tmp/gcc/libexec/gcc/x86_64-pc-linux-gnu/9.2.0/lto-wrapper
> Target: x86_64-pc-linux-gnu
> Configured with: ./configure --enable-languages=c --prefix=/tmp/gcc
> Thread model: posix
> gcc version 9.2.0 (GCC)
Although apparently the same problem appears on Arch[2].
[2]
https://lists.nongnu.org/archive/html/tinycc-devel/2019-12/msg00075.html
Thanks, Giovanni.
--- System information. ---
Architecture: Kernel: Linux 5.2.0-3-amd64
Debian Release: bullseye/sid
500 xenial updates.signal.org 500 unstable-debug
debug.mirrors.debian.org 500 unstable deb.debian.org 500
testing deb.debian.org 500 stable repo.skype.com
500 stable dl.google.com 1 experimental deb.debian.org
--- Package information. ---
Depends (Version) | Installed
============================-+-==============
gcc-9-base (= 9.2.1-21) | libc6 (>= 2.14) | libgmp10
(>= 2:5.0.1~) | libisl22 (>= 0.15) | libmpc3
| libmpfr6 (>= 3.1.3) | zlib1g (>= 1:1.1.4) |
Package's Recommends field is empty.
Suggests (Version) | Installed
============================-+-===========
gcc-9-locales (>= 8) |
--
Giovanni Mascellani <g.mascell...@gmail.com>
Postdoc researcher - Université Libre de Bruxelles
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