[Bug c/13379] New: 3.5-tree-ssa 20031210 miscompiles 2.6.0-test11 Linux kernel

["mingo at elte dot hu" <gcc-bugzilla at gcc dot gnu dot org>]

tree-ssa miscompiles the 2.6.0-test11 Linux kernel.

the kernel to fails very early during bootup. (which shows up as a 'hang'.)

after some debugging and binary searching i narrowed down the problem to
mm/bootmem.c's __alloc_bootmem_core() function. If i split out that function
into a separate module and compile that module with -fno-tree-pre then the
kernel boots and works just fine. Removing the -fno-tree-pre flag from that
module alone causes a boot failure again.

I've attached the .i and .s outputs of bootmem.c, and the cflags. You ought to
be able to compile this file standalone, without having to download the kernel tree.

-- 
           Summary: 3.5-tree-ssa 20031210 miscompiles 2.6.0-test11 Linux
                    kernel
           Product: gcc
           Version: tree-ssa
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: c
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: mingo at elte dot hu
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13379