[Bug tree-optimization/65802] [6 Regression] ICE in redirect_eh_edge_1, at tree-eh.c:2335

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65802

--- Comment #6 from vries at gcc dot gnu.org ---
(In reply to vries from comment #5)
> So the question is: should ifn_va_arg have ECF_NOTHROW?

Adding ECF_NOTHROW to ifn_va_arg also fixes the ICE.

And at gimplify_va_arg_expr, the VA_ARG_EXPR tree is non-throwing:
...
(gdb) call debug_generic_expr (*expr_p )
VA_ARG_EXPR <c>
(gdb) call debug_tree (*expr_p )
 <va_arg_expr 0x7ffff661e9a0
    type <pointer_type 0x7ffff64c97e0
        type <integer_type 0x7ffff64a7690 int public SI
            size <integer_cst 0x7ffff64c50a8 constant 32>
            unit size <integer_cst 0x7ffff64c50c0 constant 4>
            align 32 symtab 0 alias set -1 canonical type 0x7ffff64a7690
precision 32 min <integer_cst 0x7ffff64c5060 -2147483648> max <integer_cst
0x7ffff64c5078 2147483647>
            pointer_to_this <pointer_type 0x7ffff64c97e0>>
        sizes-gimplified unsigned DI
        size <integer_cst 0x7ffff64a3e58 constant 64>
        unit size <integer_cst 0x7ffff64a3e70 constant 8>
        align 64 symtab 0 alias set -1 canonical type 0x7ffff64c97e0
        pointer_to_this <pointer_type 0x7ffff6622540>>
    side-effects
    arg 0 <var_decl 0x7ffff64b0c60 c
        type <array_type 0x7ffff64ccbd0 __builtin_va_list type <record_type
0x7ffff64cc738 __va_list_tag>
            sizes-gimplified BLK
            size <integer_cst 0x7ffff64c5318 constant 192>
            unit size <integer_cst 0x7ffff64c52e8 constant 24>
            align 64 symtab 0 alias set -1 canonical type 0x7ffff64cc888 domain
<integer_type 0x7ffff64cc7e0>>
        used tree_1 decl_5 BLK file test.cc line 13 col 25 size <integer_cst
0x7ffff64c5318 192> unit size <integer_cst 0x7ffff64c52e8 24>
        align 64 context <function_decl 0x7ffff66240d8 fn1>>
    test.cc:15:32>
(gdb) call tree_could_throw_p (*expr_p )
$1 = false
...

I'll bootstrap and reg-test this fix.