> Am 23.08.2019 um 12:43 schrieb Richard Sandiford <richard.sandif...@arm.com>:
>
> Ilya Leoshkevich <i...@linux.ibm.com> writes:
>> @@ -3819,6 +3820,82 @@ can_compare_p (enum rtx_code code, machine_mode mode,
>> return 0;
>> }
>>
>> +/* can_vector_compare_p presents fake rtx binary operations to the the
>> back-end
>> + in order to determine its capabilities. In order to avoid creating fake
>> + operations on each call, values from previous calls are cached in a
>> global
>> + cached_binops hash_table. It contains rtxes, which can be looked up
>> using
>> + binop_keys. */
>> +
>> +struct binop_key {
>> + enum rtx_code code; /* Operation code. */
>> + machine_mode value_mode; /* Result mode. */
>> + machine_mode cmp_op_mode; /* Operand mode. */
>> +};
>> +
>> +struct binop_hasher : pointer_hash_mark<rtx>, ggc_cache_remove<rtx> {
>> + typedef rtx value_type;
>> + typedef binop_key compare_type;
>> +
>> + static hashval_t
>> + hash (enum rtx_code code, machine_mode value_mode, machine_mode
>> cmp_op_mode)
>> + {
>> + inchash::hash hstate (0);
>> + hstate.add_int (code);
>> + hstate.add_int (value_mode);
>> + hstate.add_int (cmp_op_mode);
>> + return hstate.end ();
>> + }
>> +
>> + static hashval_t
>> + hash (const rtx &ref)
>> + {
>> + return hash (GET_CODE (ref), GET_MODE (ref), GET_MODE (XEXP (ref, 0)));
>> + }
>> +
>> + static bool
>> + equal (const rtx &ref1, const binop_key &ref2)
>> + {
>> + return (GET_CODE (ref1) == ref2.code)
>> + && (GET_MODE (ref1) == ref2.value_mode)
>> + && (GET_MODE (XEXP (ref1, 0)) == ref2.cmp_op_mode);
>> + }
>> +};
>> +
>> +static GTY ((cache)) hash_table<binop_hasher> *cached_binops;
>> +
>> +static rtx
>> +get_cached_binop (enum rtx_code code, machine_mode value_mode,
>> + machine_mode cmp_op_mode)
>> +{
>> + if (!cached_binops)
>> + cached_binops = hash_table<binop_hasher>::create_ggc (1024);
>> + binop_key key = { code, value_mode, cmp_op_mode };
>> + hashval_t hash = binop_hasher::hash (code, value_mode, cmp_op_mode);
>> + rtx *slot = cached_binops->find_slot_with_hash (key, hash, INSERT);
>> + if (!*slot)
>> + *slot = gen_rtx_fmt_ee (code, value_mode, gen_reg_rtx (cmp_op_mode),
>> + gen_reg_rtx (cmp_op_mode));
>> + return *slot;
>> +}
>
> Sorry, I didn't mean anything this complicated. I just meant that
> we should have a single cached rtx that we can change via PUT_CODE and
> PUT_MODE_RAW for each new query, rather than allocating a new rtx each
> time.
>
> Something like:
>
> static GTY ((cache)) rtx cached_binop;
>
> rtx
> get_cached_binop (machine_mode mode, rtx_code code, machine_mode op_mode)
> {
> if (cached_binop)
> {
> PUT_CODE (cached_binop, code);
> PUT_MODE_RAW (cached_binop, mode);
> PUT_MODE_RAW (XEXP (cached_binop, 0), op_mode);
> PUT_MODE_RAW (XEXP (cached_binop, 1), op_mode);
> }
> else
> {
> rtx reg1 = gen_raw_REG (op_mode, LAST_VIRTUAL_REGISTER + 1);
> rtx reg2 = gen_raw_REG (op_mode, LAST_VIRTUAL_REGISTER + 2);
> cached_binop = gen_rtx_fmt_ee (code, mode, reg1, reg2);
> }
> return cached_binop;
> }
>
> Thanks,
> Richard
Oh, I must have completely missed the point: the cache is only for
storage, and stored values themselves don't really matter.
To make rtx usable with GTY ((cache)) I had to do:
--- a/gcc/rtl.h
+++ b/gcc/rtl.h
@@ -4427,4 +4427,9 @@ extern void gt_ggc_mx (rtx &);
extern void gt_pch_nx (rtx &);
extern void gt_pch_nx (rtx &, gt_pointer_operator, void *);
+inline void
+gt_cleare_cache (rtx)
+{
+}
+
#endif /* ! GCC_RTL_H */
Does that look ok?
Another think that might turn out being important: in your first
suggestion you use
if (insn_operand_predicate_fn pred = insn_data[icode].operand[3].predicate)
{
machine_mode cmp_mode = insn_data[icode].operand[3].mode;
instead of simply insn_operand_matches - is there any difference?
