VOIDmode in ZERO_EXTEND crashed

[Joern Rennecke]

Quoting daniel tian <daniel.xntian@gmail.com>:

> hi, everyone:
>      I have ported the gcc to new RISC chip. But when I build the
> newlib with it, the gcc crashed in simplify-rtx.c.
>      error message is like this:
>
>      ../../../../../newlib-1.16.0/newlib/libc/time/tzset_r.c: In
> function _tzset_r?
>      ../../../../../newlib-1.16.0/newlib/libc/time/tzset_r.c:195:
> internal compiler error: in simplify_const_unary_operation, at
> simplify-rtx.c:1108
>
>      And the code there is simplify-rtx.c 1108:
>
>      case ZERO_EXTEND:
> 	  /* When zero-extending a CONST_INT, we need to know its
>              original mode.  */
> 	  gcc_assert (op_mode != VOIDmode);
>
>      I tracked the gcc, It caused by the RTX   (const_int 60). As I
> know the CONST_INT is alway being VOIDmode.

That exactly is the problem.  You can't have a CONST_INT inside a
ZERO_EXTEND.  That is not valid.
You'll need a separate pattern to recognize the CONST_INT without a
ZERO_EXTEND around it.  Unfortunately, this will not give reload
the freedom it should have.