Re: [PATCH]middle-end: ensure that VEC_PERM operands get lowered to the same SSA_NAME. [PR107717]

[Richard Biener <rguenther@suse.de>]

> Am 17.11.2022 um 05:10 schrieb Tamar Christina via Gcc-patches <gcc-patches@gcc.gnu.org>:
> 
> Hi All,
> 
> At the moment when the VEC_PERMs generated by this match.pd rule is generated
> it creates two different SSA_NAMEs for the folded operand.  Because of this it
> the permute switches from a single operand permute to a two operand permute and
> the target may no longer support a permute for this.
> 
> This fixes it by ensuring we generate the same SSA_NAME for both operands.
> 
> Bootstrapped Regtested on aarch64-none-linux-gnu and no issues.
> 
> Ok for master?
> 

Ok.

Richard 

> Thanks,
> Tamar
> 
> gcc/ChangeLog:
> 
>    PR tree-optimization/107717
>    * match.pd: Ensure same SSA_NAME.
> 
> gcc/testsuite/ChangeLog:
> 
>    PR tree-optimization/107717
>    * gcc.target/aarch64/sve2/pr107717.c: New test.
> 
> --- inline copy of patch -- 
> diff --git a/gcc/match.pd b/gcc/match.pd
> index 82f05bbc912e4f80f3984d930c4a8dcb010136e1..cd510d80d409a7c52ba2a78e2fd7df0fc85cab2b 100644
> --- a/gcc/match.pd
> +++ b/gcc/match.pd
> @@ -8317,7 +8317,7 @@ and,
>  (simplify
>   (op (vec_perm @0 @0 @2) (vec_perm @1 @1 @2))
>    (if (VECTOR_INTEGER_TYPE_P (type))
> -    (vec_perm (op @0 @1) (op @0 @1) @2))))
> +    (vec_perm (op@3 @0 @1) @3 @2))))
> 
> /* Similar for float arithmetic when permutation constant covers
>    all vector elements.  */
> @@ -8356,4 +8356,4 @@ and,
>     }
>       }
>       (if (full_perm_p)
> -    (vec_perm (op @0 @1) (op @0 @1) @2))))))
> +    (vec_perm (op@3 @0 @1) @3 @2))))))
> 
> 
> 
> 
> -- 
> <rb16601.patch>