[Bug c/59679] New: gcc version 4.7.3 and gcc version 4.5.3 cause an unaligned access exception on NetBSD/Alpha

[nullnilaki at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59679

            Bug ID: 59679
           Summary: gcc version 4.7.3 and gcc version 4.5.3 cause an
                    unaligned access exception on NetBSD/Alpha
           Product: gcc
           Version: 4.7.3
            Status: UNCONFIRMED
          Severity: critical
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: nullnilaki at gmail dot com

Using gcc4.7.3 and gcc4.5.3 to compile a Perl v5.18.1.
Perl cause an unaligned access exception.
----------------------------------------------------------------

Please read the perl-bug
https://rt.perl.org/Public/Bug/Display.html?id=120888

----------------------------------------------------------------

gcc4.5 and gcc4.7 cause this problem.
(I can not compile gcc4.6 and gcc4.8 but I think gcc4.6 and gcc4.8 has some 
kind of similar bug.)

----------------------------------------------------------------

This problem was caused by compiler's bug. -ftree-ter option makes wrong
binary. 

----------------------------------------------------------------

-O2 version.

(gdb) break scope.c:1217
No source file named scope.c.
Make breakpoint pending on future shared library load? (y or [n]) y
Breakpoint 1 (scope.c:1217) pending.
(gdb) r perl.pl
Starting program: /usr/pkg/bin/perl perl.pl
[Switching to LWP 1]

Breakpoint 1, Perl_leave_scope (my_perl=0x160505000, base=<optimized out>) at 
scope.c:1217
1217                *(I8*)ARG0_PTR = (I8)(uv >> 8);
(gdb) list
1212    
1213            case SAVEt_I16:                         /* I16 reference */
1214                *(I16*)ARG0_PTR = (I16)(uv >> 8);
1215                break;
1216            case SAVEt_I8:                          /* I8 reference */
1217                *(I8*)ARG0_PTR = (I8)(uv >> 8);
1218                break;
1219            case SAVEt_DESTRUCTOR:
1220                (*arg1.any_dptr)(ARG0_PTR);
1221                break;
(gdb) x/10i $pc
=> 0x1601795c0 <Perl_leave_scope+3648>: extbl   t5,0x1,t5
   0x1601795c4 <Perl_leave_scope+3652>: ldl     t0,0(s1)
   0x1601795c8 <Perl_leave_scope+3656>: andnot  t0,0xff,t0
   0x1601795cc <Perl_leave_scope+3660>: or      t5,t0,t5
   0x1601795d0 <Perl_leave_scope+3664>: stl     t5,0(s1)
   0x1601795d4 <Perl_leave_scope+3668>: ldl     t3,48(s0)
   0x1601795d8 <Perl_leave_scope+3672>: ldl     t0,152(s0)
   0x1601795dc <Perl_leave_scope+3676>: br      0x160178800 
<Perl_leave_scope+128>
   0x1601795e0 <Perl_leave_scope+3680>: mov     s0,a0
   0x1601795e4 <Perl_leave_scope+3684>: ldq     t12,-24984(gp)
(gdb) p uv
$1 = 2574
(gdb) ptype uv
type = long unsigned int
(gdb) ptype I8
type = signed char
(gdb) print /a uv
$2 = 0xa0e
(gdb) p arg0
$1 = {any_ptr = 0x1605104ee, any_i32 = 1615922414, any_iv = 5910889710, any_uv 
= 5910889710, any_long = 5910889710, any_bool = 238, 
  any_dptr = 0x1605104ee, any_dxptr = 0x1605104ee}
(gdb) p &arg0
Address requested for identifier "arg0" which is in register $s1
(gdb) n
pid 436 (perl): unaligned access: va=0x1605104ee pc=0x1601795c4 ra=0x160179124 
sp=0x1ffffc698 op=ldl
pid 436 (perl): unaligned access: va=0x1605104ee pc=0x1601795d0 ra=0x160179124 
sp=0x1ffffc698 op=stl
1218                break;
1218                break;
(gdb) p uv
$1 = <optimized out>

-------------------------------------------------------------------

-O2 -fno-tree-ter version.

(gdb) break scope.c:1217
No source file named scope.c.
Make breakpoint pending on future shared library load? (y or [n]) y
Breakpoint 1 (scope.c:1217) pending.
(gdb) r perl.pl
Starting program: /usr/pkg/bin/perl perl.pl
[Switching to LWP 1]

Breakpoint 1, Perl_leave_scope (my_perl=0x160505000, base=<optimized out>) at 
scope.c:1217
1217                *(I8*)ARG0_PTR = (I8)(uv >> 8);
(gdb) x/10i $pc
=> 0x160177df0 <Perl_leave_scope+3664>: extbl   t5,0x1,t5
   0x160177df4 <Perl_leave_scope+3668>: ldq_u   t0,0(s1)
   0x160177df8 <Perl_leave_scope+3672>: insbl   t5,s1,t5
   0x160177dfc <Perl_leave_scope+3676>: mskbl   t0,s1,t0
   0x160177e00 <Perl_leave_scope+3680>: or      t5,t0,t5
   0x160177e04 <Perl_leave_scope+3684>: stq_u   t5,0(s1)
   0x160177e08 <Perl_leave_scope+3688>: ldl     t3,48(s0)
   0x160177e0c <Perl_leave_scope+3692>: ldl     t0,152(s0)
   0x160177e10 <Perl_leave_scope+3696>: br      0x160177020 
<Perl_leave_scope+128>
   0x160177e14 <Perl_leave_scope+3700>: unop    
(gdb) p uv
$1 = 2574
(gdb) ptype uv
type = long unsigned int
(gdb) ptype I8
type = signed char
(gdb) print /a uv
$2 = 0xa0e
(gdb) p arg0
$1 = {any_ptr = 0x1605104ee, any_i32 = 1615922414, any_iv = 5910889710, any_uv 
= 5910889710, any_long = 5910889710, any_bool = 238, 
  any_dptr = 0x1605104ee, any_dxptr = 0x1605104ee}
(gdb) n
1218                break;