Re: [RFC] optabs and tree-codes for vector operations

[Devang Patel <dpatel at apple dot com>]

One question : How to express vector operations in C that corresponds 
to RTL vec_select and vec_merge operations? In Altivec, people can use 
vec_sel() and vec_merge[h,l](), but I do not know how to express them 
without Altivec syntax.

On Aug 12, 2004, at 5:49 PM, James E Wilson wrote:

> The current RTL vec_select operator takes a parallel containing a list 
> of integers.  You are defining the tree operator VSELECT_EXPR as 
> taking a vector of condition codes, produced by a vector compare.  
> Also, vec_select takes one vector operand, and VSELECT_EXPR takes two. 
>  These are very different operations.  This could be confusing. 
> vec_select is really more like a shuffle, whereas vec_merge is more 
> like your VSELECT_EXPR.

We are following Altivec PIM vocabulary. As you say, vec_sel() 
operation is represented by vec_merge. I agree it is confusing. Do we 
have an option to rename existing RTL opertors to match Altivec PIM 
vocabulary ?

-
Devang