The following test code
-- test.c -------------------------------------
void f (int *a)
{
asm volatile(""
: "=m" (*a),
"=m" (*a),
"=m" (*a),
"=m" (*a),
"=m" (*a),
"=m" (*a),
"=m" (*a)
);
}
-----------------------------------------------
when compiled with
-----------------------------------------------
gcc -march=athlon-xp -m32 -o test.s -S test.c
-----------------------------------------------
using the following GCC
-----------------------------------------------
$ gcc -v
Using built-in specs.
Configured with: ../../../gcc-CVS-20050120/gcc-CVS-20050120/configure
--host=x86_64-pc-linux-gnu --prefix=/usr/local/opt/gcc-4.0
--exec-prefix=/usr/local/opt/gcc-4.0 --sysconfdir=/etc
--libdir=/usr/local/opt/gcc-4.0/lib64
--libexecdir=/usr/local/opt/gcc-4.0/libexec64 --sharedstatedir=/var
--localstatedir=/var --program-suffix=-4.0 --with-x-includes=/usr/X11R6/include
--with-x-libraries=/usr/X11R6/lib64 --enable-shared --enable-static
--with-gnu-as --with-gnu-ld --with-stabs --enable-threads=posix
--enable-version-specific-runtime-libs --disable-coverage
--enable-gather-detailed-mem-stats --disable-libgcj --disable-checking
--enable-multilib --with-x --enable-cmath --enable-libstdcxx-debug
--enable-fast-character --enable-hash-synchronization --with-system-zlib
--with-libbanshee --with-demangler-in-ld --with-arch=athlon64 --disable-libada
--enable-languages=c,c++,f95,objc
Thread model: posix
gcc version 4.0.0 20050120 (experimental)
$
-----------------------------------------------
or compiled by a native x86 compiler compiled from the same sources,
fails with the following error:
-----------------------------------------------
test.c: In function ‘f’:
test.c:3: error: can't find a register in class ‘GENERAL_REGS’ while reloading
‘asm’
-----------------------------------------------
It also fails the same way with the following compiler:
-----------------------------------------------
$ gcc -v
Reading specs from /usr/lib64/gcc/x86_64-mandrake-linux-gnu/3.4.1/specs
Configured with: ../configure --prefix=/usr --libdir=/usr/lib64
--with-slibdir=/lib64 --mandir=/usr/share/man --infodir=/usr/share/info
--enable-shared --enable-threads=posix --disable-checking --enable-long-long
--enable-__cxa_atexit --enable-clocale=gnu --disable-libunwind-exceptions
--enable-languages=c,c++,ada,f77,objc,java --host=x86_64-mandrake-linux-gnu
--with-system-zlib
Thread model: posix
gcc version 3.4.1 (Mandrakelinux 10.1 3.4.1-4mdk)
$
-----------------------------------------------
But when compiled natively for x86_64, both mentioned compilers work fine.
--
Summary: Register allocation problem in inline asm on x86.
Product: gcc
Version: 4.0.0
Status: UNCONFIRMED
Severity: normal
Priority: P2
Component: target
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: drab at kepler dot fjfi dot cvut dot cz
CC: gcc-bugs at gcc dot gnu dot org
GCC build triplet: i686-pc-linux-gnu
GCC host triplet: i686-pc-linux-gnu
GCC target triplet: i686-pc-linux-gnu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19549
