[Bug target/55597] internal compiler error: in plus_constant, at explow.c:88

["steven at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55597

Steven Bosscher <steven at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Target|                            |x32
                 CC|steven at gcc dot gnu.org,  |
                   |stevenb.gcc at gmail dot    |
                   |com                         |
            Summary|[4.8 Regression] internal   |internal compiler error: in
                   |compiler error: in          |plus_constant, at
                   |plus_constant, at           |explow.c:88
                   |explow.c:88                 |

--- Comment #4 from Steven Bosscher <steven at gcc dot gnu.org> 2012-12-04 23:46:01 UTC ---
Yup, target bug.

(gdb) down
#5  0x0000000000d165b2 in ix86_expand_move (mode=SImode,
operands=0x7fffffffc740) at ../../trunk/gcc/config/i386/i386.c:15936
15936           tmp = legitimize_tls_address (symbol, model, true);
(gdb) l
15931         rtx symbol = XEXP (XEXP (op1, 0), 0);
15932         rtx tmp = NULL;
15933
15934         model = SYMBOL_REF_TLS_MODEL (symbol);
15935         if (model)
15936           tmp = legitimize_tls_address (symbol, model, true);
15937         else if (TARGET_DLLIMPORT_DECL_ATTRIBUTES
15938                  && SYMBOL_REF_DLLIMPORT_P (symbol))
15939           tmp = legitimize_dllimport_symbol (symbol, true);
15940
(gdb) p debug_rtx(op0)
(reg:SI 60)
$11 = void
(gdb) p debug_rtx(op1)
(const:SI (plus:SI (symbol_ref:SI ("__morestack_initial_sp") [flags 0x10]
<var_decl 0x7ffff6301720 __morestack_initial_sp>)
        (const_int 4 [0x4])))
$12 = void
(gdb) p debug_rtx(addend)
(const_int 4 [0x4])
$13 = void
(gdb) p debug_rtx(symbol)
(symbol_ref:SI ("__morestack_initial_sp") [flags 0x10] <var_decl 0x7ffff6301720
__morestack_initial_sp>)
$14 = void
(gdb) 


Note how this tries to expand an SImode move.

Breakpoint 2, legitimize_tls_address (x=0x7ffff6401660, model=TLS_MODEL_REAL,
for_mov=true) at ../../trunk/gcc/config/i386/i386.c:12758
12758     rtx pic = NULL_RTX, tp = NULL_RTX;
(gdb) p debug_rtx(x)
(symbol_ref:SI ("__morestack_initial_sp") [flags 0x10] <var_decl 0x7ffff6301720
__morestack_initial_sp>)
$15 = void
(gdb) next
12759     enum machine_mode tp_mode = Pmode;
(gdb) 
12762     switch (model)
(gdb) 
12765         dest = gen_reg_rtx (Pmode);
(gdb) p Pmode
$16 = DImode

So now you're in trouble...

And for the record: This can never be a regression, X32 doesn't exist in
previous GCC releases.