Tree VRP bug: internal compiler error: in build_int_cst_wide, at tree.c:886

[Richard Guenther]

On 3/19/07, Andrew Haley <aph@redhat.com> wrote:
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31264
>
> This happens because we have a VIEW_CONVERT EXPR(double->long) that is
> used in a conditional.  VRP tries to register an edge assertion for
> this expression:
>
> <view_convert_expr 0x2aaaae08c6c0
>     type <integer_type 0x2aaaadfee3c0 long public DI
>         size <integer_cst 0x2aaaadfe19f0 constant invariant 64>
>         unit size <integer_cst 0x2aaaadfe1a20 constant invariant 8>
>         align 64 symtab 0 alias set -1 canonical type 0x2aaaadfee3c0 precision 64 min <integer_cst 0x2aaaadfe1930 -9223372036854775808> max <integer_cst 0x2aaaadfe1990 9223372036854775807>
>         pointer_to_this <pointer_type 0x2aaaae00e300> chain <type_decl 0x2aaaadff2270 long>>
>
>     arg 0 <ssa_name 0x2aaaae0a8f00
>         type <real_type 0x2aaaadffa6c0 double DF size <integer_cst 0x2aaaadfe19f0 64> unit size <integer_cst 0x2aaaadfe1a20 8>
>             align 64 symtab 0 alias set -1 canonical type 0x2aaaadffa6c0 precision 64
>             chain <type_decl 0x2aaaadff2d00 double>>
>         visited var <parm_decl 0x2aaaadfe7960 D.774> def_stmt <phi_node 0x2aaaae0b2d00>
>
> Which eventually works its way down to:
>
>   if (!has_single_use (op))
>     {
>       val = build_int_cst (TREE_TYPE (op), 0);
>       register_new_assert_for (op, code, val, NULL, e, bsi);
>       retval = true;
>     }
>
> and this fails with an ICE because TREE_TYPE (op) is real_type, and
> you can't build_int_cst with a real_type.
>
> The simplest way of fixing this is simply to disallow
> VIEW_CONVERT_EXPR in this context.  Comments?
>
> Index: tree-vrp.c
> ===================================================================
> --- tree-vrp.c  (revision 122839)
> +++ tree-vrp.c  (working copy)
> @@ -3485,7 +3485,6 @@
>      }
>    else if (TREE_CODE (rhs) == NOP_EXPR
>            || TREE_CODE (rhs) == CONVERT_EXPR
> -          || TREE_CODE (rhs) == VIEW_CONVERT_EXPR
>            || TREE_CODE (rhs) == NON_LVALUE_EXPR)
>      {
>        /* Recurse through the type conversion.  */

It's indeed broken to look through VIEW_CONVERT_EXPRs here.  The patch looks
obviously correct.

Thanks,
Richard.