I just tried to compile Linux kernel version 2.6.31-rc8 with the gcc 4.5 mainline snapshot 20090903 and the compiler said
arch/x86/kernel/machine_kexec_64.c: In function 'machine_kexec': arch/x86/kernel/machine_kexec_64.c:270:6: internal compiler error: in refs_may_alias_p_1, at tree-ssa-alias.c:831 Please submit a full bug report, with preprocessed source if appropriate. See <http://gcc.gnu.org/bugs.html> for instructions. Preprocessed source attached. Flags -O2 -fprofile-arcs required. -- Summary: ice with -O2 -fprofile-arcs when compiling Linux kernel Product: gcc Version: 4.5.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: dcb314 at hotmail dot com GCC host triplet: x86_64-suse-linux http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41261