On Fri, May 11, 2018 at 2:44 AM, Andi Kleen <a...@firstfloor.org> wrote:
>> @@ -31325,7 +31329,21 @@ ix86_init_mmx_sse_builtins (void)
>> continue;
>>
>> ftype = (enum ix86_builtin_func_type) d->flag;
>> - def_builtin2 (d->mask, d->name, ftype, d->code);
>> + decl = def_builtin2 (d->mask, d->name, ftype, d->code);
>> +
>> + /* Avoid edges for ptwrites generated by vartrace pass. */
>> + if (decl)
>> + {
>> + DECL_ATTRIBUTES (decl) = build_tree_list (get_identifier ("leaf"),
>> + NULL_TREE);
>> + TREE_NOTHROW (decl) = 1;
>> + }
>> + else
>> + {
>> + ix86_builtins_isa[(int)d->code].leaf_p = true;
>> + ix86_builtins_isa[(int)d->code].nothrow_p = true;
>> + }
>> +
>>
>> Can you please explain what is the purpose of the above change?
>
> With the vartrace patch, which was the next patch in the original
> patchkit, the compiler can generate a lot of ptwrite builtins,
> and adding so many edges can slow it down. I originally copied
> this from the MPX builtins (which had the same problem).
Please add new def_builtin_noedge2 (or something appropriately named)
aux function and declare these two new builtins manually in
ix86_init_mmx_sse_builtins.
Uros.
