[Bug rtl-optimization/49230] please provide workaround for setjmp/longjmp in mingw32

["jojelino at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49230

gee <jojelino at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |UNCONFIRMED
         Resolution|INVALID                     |

--- Comment #7 from gee <jojelino at gmail dot com> 2011-06-29 19:35:20 UTC ---
(In reply to comment #3)
> As register ebp is used by gcc as internal frame-register. Even if you are
> specifying -fomit-frame-pointer as option, the main function will still have a
> frame-pointer setup. Also ebp-register is a callee-saved register, which means
> its use as local-register variable is in general nothing wise to do.

maybe the following could be counterexample.
this code is from gcc 2011110622.
ebp may be not internal frame pointer.
so in this case setjmp can store invalid ebp.
nlg_notify dereferences ebp,causing sigsegv
not only it don't use framepointer, but also it doesn't restore framepointer

LFE104:
    .p2align 4,,15
    .globl    _rb_ensure
    .def    _rb_ensure;    .scl    2;    .type    32;    .endef
_rb_ensure:
LFB105:
    .loc 2 727 0 is_stmt 1
    .cfi_startproc
LVL835:
    pushl    %ebx
LCFI228:
    .cfi_def_cfa_offset 8
    .cfi_offset 3, -8
    subl    $120, %esp
LCFI229:
    .cfi_def_cfa_offset 128
LBB566:
    .loc 2 731 0
    movl    _ruby_current_thread, %eax
LBE566:
    .loc 2 729 0
    movl    $4, 32(%esp)
LVL836:
LBB567:
    .loc 2 731 0
    movl    $0, 100(%esp)
    movl    %eax, %edx
    movl    %eax, 28(%esp)
LVL837:
    movl    152(%eax), %eax
    movl    %eax, 108(%esp)
    leal    36(%esp), %eax
    movl    %eax, 152(%edx)
    .loc 2 732 0
    movl    %eax, (%esp)
    call    __setjmp
LVL838:
    testl    %eax, %eax
    movl    %eax, %ebx
LVL839:
    je    L733
    .loc 2 735 0
    movl    108(%esp), %eax
LVL840:
    movl    28(%esp), %edx
    movl    %eax, 152(%edx)
LBE567:
    .loc 2 738 0
    movl    140(%esp), %eax
    movl    %eax, (%esp)
    call    *136(%esp)
LVL841:
    .loc 2 740 0
    movl    _ruby_current_thread, %eax
    movl    %ebx, 4(%esp)
    movl    152(%eax), %eax
    movl    %eax, (%esp)
    call    _longjmp
LVL842:
    .p2align 4,,10
L733:
LBB568:
    .loc 2 733 0
    movl    132(%esp), %eax
    movl    %eax, (%esp)
    call    *128(%esp)
LVL843:
    .loc 2 735 0
    movl    28(%esp), %edx
    .loc 2 733 0
    movl    %eax, 32(%esp)
    .loc 2 735 0
    movl    108(%esp), %eax
    movl    %eax, 152(%edx)
LBE568:
    .loc 2 738 0
    movl    140(%esp), %eax
    movl    %eax, (%esp)
    call    *136(%esp)
LVL844:
    .loc 2 741 0
    movl    32(%esp), %eax
    .loc 2 742 0
    addl    $120, %esp
LCFI230:
    .cfi_def_cfa_offset 8
    popl    %ebx
LCFI231:
    .cfi_def_cfa_offset 4
    .cfi_restore 3
LVL845:
    ret
    .cfi_endproc
LFE105:
    .p2align 4,,15
    .globl    _rb_frame_this_func
    .def    _rb_frame_this_func;    .scl    2;    .type    32;    .endef
_rb_frame_this_func:
LFB108:
    .loc 2 791 0
    .cfi_startproc
    .loc 2 792 0
    movl    _ruby_current_thread, %eax
    movl    16(%eax), %eax
    jmp    _frame_func_id
LVL846:
    .cfi_endproc
LFE108: