On Thu, Nov 30, 2023 at 12:11 PM juzhe.zh...@rivai.ai <juzhe.zh...@rivai.ai>
wrote:
> BIAS should be:
>
> signed char biasval
> = LOOP_VINFO_PARTIAL_LOAD_STORE_BIAS (loop_vinfo);
> tree bias = build_int_cst (intQI_type_node, biasval);
>
> Currently, only IBM will set LOOP_VINFO_PARTIAL_LOAD_STORE_BIAS -1 for
> some situations of len_load/len_store.
> Otherwise, it is always 0.
> But for consistency, I think we should use the codes as follows.
>
> I see your patch is so big and separate into multiple sub-patches.
> Do you have a patch that directly can be applied for whole support.
> I want to support length and test that base your patch.
>
Can we defer LEN support for a followup? I think we still need to set
partial loop support
as disabled when there are any lengths with the initial patch for
correctness.
Richard.
> Thanks.
>
> ------------------------------
> juzhe.zh...@rivai.ai
>
>
> *From:* Tamar Christina <tamar.christ...@arm.com>
> *Date:* 2023-11-30 18:58
> *To:* juzhe.zh...@rivai.ai; gcc-patches <gcc-patches@gcc.gnu.org>
> *CC:* Richard Biener <richard.guent...@gmail.com>
> *Subject:* RE: RE: [PATCH 9/21]middle-end: implement
> vectorizable_early_exit for codegen of exit code
>
> Hi Juzhe,
>
>
>
> I meant that “lens” is undefined, from looking around I guess that needs
> to be
>
>
>
> vec_loop_lens *lens = &LOOP_VINFO_LENS (loop_vinfo);
>
>
>
> for `bias` I meant
>
>
>
> cond = gimple_build (&cond_gsi, IFN_VCOND_MASK_LEN, truth_type,
>
> all true mask, cond, all false mask, len, bias);
>
>
>
> that variable `bias` isn’t defined. And I can’t find any other usage of
> IFN_VCOND_MASK_LEN creation to figure out what it’s supposed to be
>
>
>
> is it just an SImode 0?
>
>
>
> Thanks,
>
> Tamar
>
>
>
>
>
> *From:* juzhe.zh...@rivai.ai <juzhe.zh...@rivai.ai>
> *Sent:* Thursday, November 30, 2023 11:49 AM
> *To:* Tamar Christina <tamar.christ...@arm.com>; gcc-patches <
> gcc-patches@gcc.gnu.org>
> *Cc:* Richard Biener <richard.guent...@gmail.com>
> *Subject:* Re: RE: [PATCH 9/21]middle-end: implement
> vectorizable_early_exit for codegen of exit code
>
>
>
> Thanks Tamar.
>
>
>
> I am not sure whether I am not on the same page with you.
>
>
>
> IMHO, ARM SVE will use the final mask = loop mask (generate by WHILE_ULT)
> & conditional mask.
>
> Use that final mask to do the cbranch. Am I right ?
>
>
>
> If yes, I leverage that for length and avoid too much codes change in your
> patch.
>
>
>
> So, for RVV, the length is pretty same as loop mask in ARM SVE.
>
> For example, suppose n = 4, in ARM SVE, WHILE_ULT (whilelo) generate mask
> = 0b11110000000....
>
> Then use that mask to control the operations.
>
>
>
> For RVV, is the same, length will be 4, then we will only process the
> elements with index < 4.
>
>
>
> For bias, I think that won't be the issue. Currently, BIAS is not used by
> RVV and only used on len_load/len_store for IBM targets.
>
> So, the bias value by default is 0 in all other situations except
> len_load/len_store specifically for IBM.
>
>
> ------------------------------
>
> juzhe.zh...@rivai.ai
>
>
>
> *From:* Tamar Christina <tamar.christ...@arm.com>
>
> *Date:* 2023-11-30 18:39
>
> *To:* juzhe.zh...@rivai.ai; gcc-patches <gcc-patches@gcc.gnu.org>
>
> *CC:* Richard Biener <richard.guent...@gmail.com>
>
> *Subject:* RE: [PATCH 9/21]middle-end: implement vectorizable_early_exit
> for codegen of exit code
>
> Hi Juzhe,
>
>
>
> I’m happy to take the hunks, just that I can’t test it and don’t know the
> specifics of how it lens work.
>
> I still need to read up on it.
>
>
>
> I tried adding that chunk in, but for the first bit `lens` seems
> undefined, and the second bit it seems `bias` is undefined.
>
>
>
> I’ll also need what to do for vectorizable_live_operations how to get the
> first element rather than the last.
>
>
>
> Thanks,
>
> Tamar
>
>
>
> *From:* juzhe.zh...@rivai.ai <juzhe.zh...@rivai.ai>
> *Sent:* Thursday, November 30, 2023 4:48 AM
> *To:* gcc-patches <gcc-patches@gcc.gnu.org>
> *Cc:* Richard Biener <richard.guent...@gmail.com>; Tamar Christina <
> tamar.christ...@arm.com>
> *Subject:* [PATCH 9/21]middle-end: implement vectorizable_early_exit for
> codegen of exit code
>
>
>
> Hi, Richard and Tamar.
>
>
>
> I am sorry for bothering you.
>
> Hope you don't mind I give some comments:
>
>
>
> Can we support partial vector for length ?
>
>
>
> IMHO, we can do that as follows:
>
>
>
> bool length_loop_p = LOOP_VINFO_FULLY_WITH_LENGTH_P (loop_vinfo);
>
>
>
> if (LOOP_VINFO_CAN_USE_PARTIAL_VECTORS_P (loop_vinfo))
>
> {
>
> if (direct_internal_fn_supported_p (IFN_VCOND_MASK_LEN, vectype,
>
> OPTIMIZE_FOR_SPEED))
>
> vect_record_loop_len (loop_vinfo, lens, ncopies, vectype, 1);
>
> else
>
> vect_record_loop_mask (loop_vinfo, masks, ncopies, truth_type, NULL
> );
>
> }
>
>
>
> if (length_loop_p)
>
> {
>
> tree len = vect_get_loop_len (loop_vinfo, gsi, loop_lens, 1, vectype,
> 0, 0);
>
> /* Use VCOND_MASK_LEN (all true, cond, all false, len, bias) to
> generate
>
> final mask = i < len + bias ? cond[i] : false. */
>
> cond = gimple_build (&cond_gsi, IFN_VCOND_MASK_LEN, truth_type,
>
> all true mask, cond, all false mask, len, bias);
>
> }
>
> else if (masked_loop_p)
>
> {
>
> tree mask
>
> = vect_get_loop_mask (loop_vinfo, gsi, masks, ncopies, truth_type, 0
> );
>
> cond
>
> = prepare_vec_mask (loop_vinfo, TREE_TYPE (mask), mask, cond, &
> cond_gsi);
>
> }
>
>
>
> This is a prototype. Is this idea reasonable to Richi ?
>
>
>
> Thanks.
>
>
> ------------------------------
>
> juzhe.zh...@rivai.ai
>
>
