Ok . Thanks Richard.

Could you give me a case that SVE can vectorize a reduction with FMA?
Meaning it will go into vectorize_call and vectorize FMA into COND_FMA ?

I tried many times to reproduce such cases but I failed.

Thanks.


juzhe.zh...@rivai.ai
 
From: Richard Sandiford
Date: 2023-07-31 18:19
To: Juzhe-Zhong
CC: gcc-patches; rguenther
Subject: Re: [PATCH V2] VECT: Support CALL vectorization for COND_LEN_*
Juzhe-Zhong <juzhe.zh...@rivai.ai> writes:
> Hi, Richard and Richi.
>
> Base on the suggestions from Richard:
> https://gcc.gnu.org/pipermail/gcc-patches/2023-July/625396.html
>
> This patch choose (1) approach that Richard provided, meaning:
>
> RVV implements cond_* optabs as expanders.  RVV therefore supports
> both IFN_COND_ADD and IFN_COND_LEN_ADD.  No dummy length arguments
> are needed at the gimple level.
>
> Such approach can make codes much cleaner and reasonable.
>
> Consider this following case:
> void foo (float * __restrict a, float * __restrict b, int * __restrict cond, 
> int n)
> {
>   for (int i = 0; i < n; i++)
>     if (cond[i])
>       a[i] = b[i] + a[i];
> }
>
>
> Output of RISC-V (32-bits) gcc (trunk) (Compiler #3)
> <source>:5:21: missed: couldn't vectorize loop
> <source>:5:21: missed: not vectorized: control flow in loop.
>
> ARM SVE:
>
> ...
> mask__27.10_51 = vect__4.9_49 != { 0, ... };
> ...
> vec_mask_and_55 = loop_mask_49 & mask__27.10_51;
> ...
> vect__9.17_62 = .COND_ADD (vec_mask_and_55, vect__6.13_56, vect__8.16_60, 
> vect__6.13_56);
>
> For RVV, we want IR as follows:
>
> ...
> _68 = .SELECT_VL (ivtmp_66, POLY_INT_CST [4, 4]);
> ...
> mask__27.10_51 = vect__4.9_49 != { 0, ... };
> ...
> vect__9.17_60 = .COND_LEN_ADD (mask__27.10_51, vect__6.13_55, vect__8.16_59, 
> vect__6.13_55, _68, 0);
> ...
>
> Both len and mask of COND_LEN_ADD are real not dummy.
>
> This patch has been fully tested in RISC-V port with supporting both COND_* 
> and COND_LEN_*.
>
> And also, Bootstrap and Regression on X86 passed.
>
> OK for trunk?
>
> gcc/ChangeLog:
>
>         * internal-fn.cc (FOR_EACH_LEN_FN_PAIR): New macro.
>         (get_len_internal_fn): New function.
>         (CASE): Ditto.
>         * internal-fn.h (get_len_internal_fn): Ditto.
>         * tree-vect-stmts.cc (vectorizable_call): Support CALL vectorization 
> with COND_LEN_*.
>
> ---
>  gcc/internal-fn.cc     | 46 ++++++++++++++++++++++
>  gcc/internal-fn.h      |  1 +
>  gcc/tree-vect-stmts.cc | 87 +++++++++++++++++++++++++++++++++++++-----
>  3 files changed, 125 insertions(+), 9 deletions(-)
>
> diff --git a/gcc/internal-fn.cc b/gcc/internal-fn.cc
> index 8e294286388..379220bebc7 100644
> --- a/gcc/internal-fn.cc
> +++ b/gcc/internal-fn.cc
> @@ -4443,6 +4443,52 @@ get_conditional_internal_fn (internal_fn fn)
>      }
>  }
>  
> +/* Invoke T(IFN) for each internal function IFN that also has an
> +   IFN_COND_LEN_* or IFN_MASK_LEN_* form.  */
> +#define FOR_EACH_LEN_FN_PAIR(T)                                              
>   \
> +  T (MASK_LOAD, MASK_LEN_LOAD)                                               
>   \
> +  T (MASK_STORE, MASK_LEN_STORE)                                             
>   \
> +  T (MASK_GATHER_LOAD, MASK_LEN_GATHER_LOAD)                                 
>   \
> +  T (MASK_SCATTER_STORE, MASK_LEN_SCATTER_STORE)                             
>   \
> +  T (COND_ADD, COND_LEN_ADD)                                                 
>   \
> +  T (COND_SUB, COND_LEN_SUB)                                                 
>   \
> +  T (COND_MUL, COND_LEN_MUL)                                                 
>   \
> +  T (COND_DIV, COND_LEN_DIV)                                                 
>   \
> +  T (COND_MOD, COND_LEN_MOD)                                                 
>   \
> +  T (COND_RDIV, COND_LEN_RDIV)                                               
>   \
> +  T (COND_FMIN, COND_LEN_FMIN)                                               
>   \
> +  T (COND_FMAX, COND_LEN_FMAX)                                               
>   \
> +  T (COND_MIN, COND_LEN_MIN)                                                 
>   \
> +  T (COND_MAX, COND_LEN_MAX)                                                 
>   \
> +  T (COND_AND, COND_LEN_AND)                                                 
>   \
> +  T (COND_IOR, COND_LEN_IOR)                                                 
>   \
> +  T (COND_XOR, COND_LEN_XOR)                                                 
>   \
> +  T (COND_SHL, COND_LEN_SHL)                                                 
>   \
> +  T (COND_SHR, COND_LEN_SHR)                                                 
>   \
> +  T (COND_NEG, COND_LEN_NEG)                                                 
>   \
> +  T (COND_FMA, COND_LEN_FMA)                                                 
>   \
> +  T (COND_FMS, COND_LEN_FMS)                                                 
>   \
> +  T (COND_FNMA, COND_LEN_FNMA)                                               
>   \
> +  T (COND_FNMS, COND_LEN_FNMS)
 
With the earlier patch to add DEF_INTERNAL_COND_FN and
DEF_INTERNAL_SIGNED_COND_FN, I think we should use those to handle
the COND_* cases, rather than putting them in this macro.
 
Thanks,
Richard
 

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