Thanks for the comments.

I will fix doc's description as you suggested.

I personally prefer **NOT** to include BIAS in the gather/scatter since I don't known how it will be used.

Let's wait for Richi or Richard more comments.

Thanks.


juzhe.zhong@rivai.ai
 
From: Robin Dapp
Date: 2023-06-29 23:04
To: juzhe.zhong; gcc-patches
CC: rdapp.gcc; richard.sandiford; rguenther
Subject: Re: [PATCH] Machine Description: Add LEN_MASK_{GATHER_LOAD, SCATTER_STORE} pattern
Hi Juzhe,
 
just looking at the documentation changes.
 
> +@cindex @code{len_mask_gather_load@var{m}@var{n}} instruction pattern
> +@item @samp{len_mask_gather_load@var{m}@var{n}}
> +Like @samp{gather_load@var{m}@var{n}}, but takes an extra len operand
> +as operand 5 and an extra mask operand as operand 6.  Bit @var{i} of
> +the mask is set and i < len if element @var{i} of the result should be
> +loaded from memory.  Element @var{i} of the result should be undefined
> +value when either Bit @var{i} of the mask is clear or i >= len.
> +
 
I would suggest to rephrase this slightly as:
 
"Like ... but takes an extra length operand (operand 5) as well as a
mask operand (operand 6).  Similar to len_maskload, the instruction
loads at most (operand 5) elements from memory.  
Bit @var{i} of the mask is set if element @var{i} of the result should
be loaded from memory and clear if element @var{i} of the result
should be undefined.  Mask elements @var{i} with i > (operand 5) are
ignored."
 
to make it more similar to mask_gather_load.  Further improvements
welcome though - not sure if we should refer to len_maskload at all
because it has a bias operand and mask_gather_load doesn't.
 
> +@cindex @code{len_mask_scatter_store@var{m}@var{n}} instruction pattern
> +@item @samp{len_mask_scatter_store@var{m}@var{n}}
> +Like @samp{scatter_store@var{m}@var{n}}, but takes an extra len operand as
> +operand 5 and an extra mask operand as operand 6.  Bit @var{i} of the mask
> +is set and i < len if element @var{i} of the result should be stored to memory.
> +
"an extra length operand (operand 5)... The instruction stores
at most (operand 5) elements of (operand 4) to memory.
Bit @var{i} of the mask is set if element @var{i} of (operand 4)
should be stored.  Mask elements @var{i} with i > (operand 5) are
ignored."
 
Regards
Robin