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

On Fri, 14 Aug 2026, Tamar Christina wrote:

> > -----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?

I think it will disrupt the stmt walking, it can't be part of two
lists at the same time.

Richard.

> 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
> 
> 

-- 
Richard Biener <[email protected]>
SUSE Software Solutions Germany GmbH,
Frankenstrasse 146, 90461 Nuernberg, Germany;
GF: Jochen Jaser, Andrew McDonald, Abhinav Puri; (HRB 36809, AG Nuernberg)