Compiling the following with -O0 works. Compiling with -O2 produces assembly syntax errors.
Using built-in specs. Target: i686-pc-linux-gnu Configured with: /var/tmp/portage/sys-devel/gcc-4.3.1-r1/work/gcc-4.3.1/configure --prefix=/usr --bindir=/usr/i686-pc-linux-gnu/gcc-bin/4.3.1 --includedir=/usr/lib/gcc/i686-pc-linux-gnu/4.3.1/include --datadir=/usr/share/gcc-data/i686-pc-linux-gnu/4.3.1 --mandir=/usr/share/gcc-data/i686-pc-linux-gnu/4.3.1/man --infodir=/usr/share/gcc-data/i686-pc-linux-gnu/4.3.1/info --with-gxx-include-dir=/usr/lib/gcc/i686-pc-linux-gnu/4.3.1/include/g++-v4 --host=i686-pc-linux-gnu --build=i686-pc-linux-gnu --disable-altivec --enable-nls --without-included-gettext --with-system-zlib --disable-checking --disable-werror --enable-secureplt --disable-multilib --enable-libmudflap --disable-libssp --enable-cld --enable-java-awt=gtk --with-arch=i686 --enable-languages=c,c++,java,treelang --enable-shared --enable-threads=posix --enable-__cxa_atexit --enable-clocale=gnu --with-bugurl=http://bugs.gentoo.org/ --with-pkgversion='Gentoo 4.3.1-r1 p1.1' Thread model: posix gcc version 4.3.1 (Gentoo 4.3.1-r1 p1.1) #include <stdio.h> void test(unsigned int val) { unsigned int res, resz; asm( " xorl %1, %1\n" " movl $0x12345678, %0\n" " bsrl %2, %0 ; setz %b1 " : "=r" (res), "=r" (resz) : "g" (val) ); printf("val : %d\n", val); printf("res : %d\n", res); printf("resz: %d\n", resz); } int main() { test(0); test(1 << 7); test(1 << 15); test(1 << 30); return 0; } -- Summary: optimization causes inline assembler to emit syntax errors Product: gcc Version: 4.3.1 Status: UNCONFIRMED Severity: normal Priority: P3 Component: inline-asm AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: zeev dot tarantov at gmail dot com http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37492
