RE: [PATCH 1/2] Add vect_finish_stmt_generation for sequences

> -----Original Message-----
> From: Richard Biener <[email protected]>
> Sent: 14 August 2026 13:13
> To: [email protected]
> Cc: Tamar Christina <[email protected]>
> Subject: [PATCH 1/2] Add vect_finish_stmt_generation for sequences
> 
> The following attempts to make using gimple_build easier during
> vectorizer code generation by providing an overload of
> vect_finish_stmt_generation that handles a built sequence.
> In addition to inserting and finishing stmts on the sequence the
> ultimate result is made to be based on the passed vectorizer
> temporary (that gets us the fancy names).
> 
> I have converted one instance in vectorizable_conversion which
> I'll need to handle both NOP_EXPR and VIEW_CONVERT_EXPR which
> gimple_build happily does correctly, but vect_gimple_build does
> not.
> 
> Bootstrapped and tested on x86_64-unknown-linux-gnu.
> 
> Does this look sensible?  I can of course sepecial-case
> VIEW_CONVERT_EXPR manually as well.
> 

Yeah, it seems useful especially for cleaning up vectorizable_load/store
where we have a lot of additional addressing variables being emitted
all over the place.

> 	* tree-vect-stmts.cc (vect_finish_stmt_generation): New
> 	overload for gimple_build sequences.
> 	(vectorizable_conversion): Convert one instance of
> 	vect_gimple_build to gimple_build plus
> 	vect_finish_stmt_generation.
> ---
>  gcc/tree-vect-stmts.cc | 43 ++++++++++++++++++++++++++++++++---------
> -
>  1 file changed, 33 insertions(+), 10 deletions(-)
> 
> diff --git a/gcc/tree-vect-stmts.cc b/gcc/tree-vect-stmts.cc
> index a023977bc51..44090015e7a 100644
> --- a/gcc/tree-vect-stmts.cc
> +++ b/gcc/tree-vect-stmts.cc
> @@ -1260,7 +1260,7 @@ vect_get_vec_defs (vec_info *, slp_tree slp_node,
> 
>  /* Helper function called by vect_finish_replace_stmt and
>     vect_finish_stmt_generation.  Set the location of the new
> -   statement and create and return a stmt_vec_info for it.  */
> +   statement.  */
> 
>  static void
>  vect_finish_stmt_generation_1 (vec_info *,
> @@ -1285,8 +1285,7 @@ vect_finish_stmt_generation_1 (vec_info *,
>  }
> 
>  /* Replace the scalar statement STMT_INFO with a new vector statement
> VEC_STMT,
> -   which sets the same scalar result as STMT_INFO did.  Create and return a
> -   stmt_vec_info for VEC_STMT.  */
> +   which sets the same scalar result as STMT_INFO did.  */
> 
>  void
>  vect_finish_replace_stmt (vec_info *vinfo,
> @@ -1302,7 +1301,7 @@ vect_finish_replace_stmt (vec_info *vinfo,
>  }
> 
>  /* Add VEC_STMT to the vectorized implementation of STMT_INFO and insert
> it
> -   before *GSI.  Create and return a stmt_vec_info for VEC_STMT.  */
> +   before *GSI.  */
> 
>  void
>  vect_finish_stmt_generation (vec_info *vinfo,
> @@ -1344,6 +1343,31 @@ vect_finish_stmt_generation (vec_info *vinfo,
>    vect_finish_stmt_generation_1 (vinfo, stmt_info, vec_stmt);
>  }
> 
> +/* Add the stmts in STMTS to the vectorized implementation of STMT_INFO
> and
> +   insert them before *GSI.  Make sure the final stmt has a result
> +   based on VAR.  */
> +
> +void
> +vect_finish_stmt_generation (vec_info *vinfo,
> +			     stmt_vec_info stmt_info, gimple_seq &stmts,
> +			     tree var, gimple_stmt_iterator *gsi)
> +{
> +  auto si = gsi_start (stmts);
> +  while (!gsi_end_p (si))
> +    {
> +      gimple *new_stmt = gsi_stmt (si);
> +      gsi_remove (&si, false);

Do we actually need to remove the stmts since they're not in IL?
would it not be easier to just leave it and do stmts = NULL; at the
end since it saves the ptr updating?

Cheers,
Tamar

> +      if (gsi_end_p (si))
> +	{
> +	  tree lhs = gimple_get_lhs (new_stmt);
> +	  gcc_assert (!SSA_NAME_VAR (lhs));
> +	  SET_SSA_NAME_VAR_OR_IDENTIFIER (lhs, var);
> +	}
> +      vect_finish_stmt_generation (vinfo, stmt_info, new_stmt, gsi);
> +    }
> +}
> +
> +
>  /* We want to vectorize a call to combined function CFN with function
>     decl FNDECL, using VECTYPE_OUT as the type of the output and
> VECTYPE_IN
>     as the types of all inputs.  Check whether this is possible using
> @@ -5797,12 +5821,11 @@ vectorizable_conversion (vec_info *vinfo,
>  	    }
>  	  else
>  	    {
> -	      new_stmt = vect_gimple_build (vec_dest, code1, vop0);
> -	      new_temp = make_ssa_name (vec_dest, new_stmt);
> -	      gimple_set_lhs (new_stmt, new_temp);
> -	      vect_finish_stmt_generation (vinfo, stmt_info, new_stmt, gsi);
> -
> -	      slp_node->push_vec_def (new_stmt);
> +	      gimple_seq stmts = NULL;
> +	      new_temp = gimple_build (&stmts, code1, vectype_out, vop0);
> +	      vect_finish_stmt_generation (vinfo, stmt_info,
> +					   stmts, vec_dest, gsi);
> +	      slp_node->push_vec_def (new_temp);
>  	    }
>  	}
>        break;
> --
> 2.51.0