http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49595
Summary: on amd64, sizeof(__int128_t) > sizeof(intmax_t) Product: gcc Version: 4.6.2 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c AssignedTo: unassig...@gcc.gnu.org ReportedBy: sand...@crustytoothpaste.net Created attachment 24647 --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=24647 Trivial testcase The C standard (as well as POSIX) requires that intmax_t "designates a signed integer type capable of representing any value of any signed integer type" and likewise for uintmax_t. However, on amd64, intmax_t is long, which is not big enough to hold a 128-bit quantity. A trivial preprocessed testcase is attached, not that you need one. I see this behavior on 4.6 and 4.7: lakeview ok % gcc -v Using built-in specs. COLLECT_GCC=gcc COLLECT_LTO_WRAPPER=/usr/lib/x86_64-linux-gnu/gcc/x86_64-linux-gnu/4.6.1/lto-wrapper Target: x86_64-linux-gnu Configured with: ../src/configure -v --with-pkgversion='Debian 4.6.1-1' --with-bugurl=file:///usr/share/doc/gcc-4.6/README.Bugs --enable-languages=c,c++,fortran,objc,obj-c++,go --prefix=/usr --program-suffix=-4.6 --enable-shared --enable-multiarch --with-multiarch-defaults=x86_64-linux-gnu --enable-linker-build-id --with-system-zlib --libexecdir=/usr/lib/x86_64-linux-gnu --without-included-gettext --enable-threads=posix --with-gxx-include-dir=/usr/include/c++/4.6 --libdir=/usr/lib/x86_64-linux-gnu --enable-nls --enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes --enable-plugin --enable-objc-gc --with-arch-32=i586 --with-tune=generic --enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu Thread model: posix gcc version 4.6.1 (Debian 4.6.1-1) lakeview ok % /usr/lib/gcc-snapshot/bin/gcc -v Using built-in specs. COLLECT_GCC=/usr/lib/gcc-snapshot/bin/gcc COLLECT_LTO_WRAPPER=/usr/lib/gcc-snapshot/libexec/gcc/x86_64-linux-gnu/4.7.0/lto-wrapper Target: x86_64-linux-gnu Configured with: ../src/configure -v --with-pkgversion='Debian 20110624-1' --with-bugurl=file:///usr/share/doc/gcc-snapshot/README.Bugs --enable-languages=c,ada,c++,java,fortran,objc,obj-c++,go --prefix=/usr/lib/gcc-snapshot --enable-shared --enable-multiarch --with-multiarch-defaults=x86_64-linux-gnu --enable-linker-build-id --with-system-zlib --disable-nls --enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes --enable-plugin --disable-browser-plugin --enable-java-awt=gtk --enable-gtk-cairo --with-java-home=/usr/lib/jvm/java-1.5.0-gcj-4.7-snap/jre --enable-java-home --with-jvm-root-dir=/usr/lib/jvm/java-1.5.0-gcj-4.7-snap --with-jvm-jar-dir=/usr/lib/jvm-exports/java-1.5.0-gcj-4.7-snap --with-arch-directory=amd64 --with-ecj-jar=/usr/share/java/eclipse-ecj.jar --enable-objc-gc --with-arch-32=i586 --with-tune=generic --disable-werror --enable-checking=yes --build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu Thread model: posix gcc version 4.7.0 20110624 (experimental) [trunk revision 175388] (Debian 20110624-1) This is Debian bug #629137.