[gcc r16-5314] Do not call vect_determine_partial_vectors_and_peeling from transform

[Richard Biener]

https://gcc.gnu.org/g:c6008611e9678991c763944ae8539aa90cad419d

commit r16-5314-gc6008611e9678991c763944ae8539aa90cad419d
Author: Richard Biener <rguenther@suse.de>
Date:   Fri Nov 14 14:10:24 2025 +0100

    Do not call vect_determine_partial_vectors_and_peeling from transform
    
    It gets more difficult to maintain this doesn't do any changes late
    (see followups), so kill it.  We do have to retain re-setting of
    LOOP_VINFO_PEELING_FOR_NITER though, since
    vect_need_peeling_or_partial_vectors_p is incorrect for epilogues
    when done during analysis.  We should fix this of course.
    
            * tree-vectorizer.h (vect_determine_partial_vectors_and_peeling):
            Remove.
            (vect_need_peeling_or_partial_vectors_p): Declare.
            * tree-vect-loop.cc (vect_determine_partial_vectors_and_peeling):
            Make static.
            (vect_need_peeling_or_partial_vectors_p): Export.
            * tree-vect-loop-manip.cc (vect_do_peeling): Do not call
            vect_determine_partial_vectors_and_peeling but instead
            re-compute LOOP_VINFO_PEELING_FOR_NITER using
            vect_need_peeling_or_partial_vectors_p.

Diff:
---
 gcc/tree-vect-loop-manip.cc | 11 +++++------
 gcc/tree-vect-loop.cc       |  4 ++--
 gcc/tree-vectorizer.h       |  2 +-
 3 files changed, 8 insertions(+), 9 deletions(-)

diff --git a/gcc/tree-vect-loop-manip.cc b/gcc/tree-vect-loop-manip.cc
index 3e121a96ddf0..af3f3aff2cc0 100644
--- a/gcc/tree-vect-loop-manip.cc
+++ b/gcc/tree-vect-loop-manip.cc
@@ -3726,12 +3726,11 @@ vect_do_peeling (loop_vec_info loop_vinfo, tree niters, tree nitersm1,
 		       epilogue_niters,
 		       build_one_cst (TREE_TYPE (epilogue_niters)));
 
-      /* Decide what to do if the number of epilogue iterations is not
-	 a multiple of the epilogue loop's vectorization factor.
-	 We should have rejected the loop during the analysis phase
-	 if this fails.  */
-      bool res = vect_determine_partial_vectors_and_peeling (epilogue_vinfo);
-      gcc_assert (res);
+      /* ???  During analysis phase this is computed wrongly, re-do it
+	 here.  */
+      LOOP_VINFO_PEELING_FOR_NITER (epilogue_vinfo)
+	= (!LOOP_VINFO_USING_PARTIAL_VECTORS_P (epilogue_vinfo)
+	   && vect_need_peeling_or_partial_vectors_p (epilogue_vinfo));
     }
 
   adjust_vec.release ();
diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc
index e5a3971f1501..0d5c3dddc422 100644
--- a/gcc/tree-vect-loop.cc
+++ b/gcc/tree-vect-loop.cc
@@ -937,7 +937,7 @@ vect_min_prec_for_max_niters (loop_vec_info loop_vinfo, unsigned int factor)
 
 /* True if the loop needs peeling or partial vectors when vectorized.  */
 
-static bool
+bool
 vect_need_peeling_or_partial_vectors_p (loop_vec_info loop_vinfo)
 {
   unsigned HOST_WIDE_INT const_vf;
@@ -2004,7 +2004,7 @@ vect_get_datarefs_in_loop (loop_p loop, basic_block *bbs,
 
  */
 
-opt_result
+static opt_result
 vect_determine_partial_vectors_and_peeling (loop_vec_info loop_vinfo)
 {
   /* Determine whether there would be any scalar iterations left over.  */
diff --git a/gcc/tree-vectorizer.h b/gcc/tree-vectorizer.h
index c07fcb42d508..55f0bee0eb74 100644
--- a/gcc/tree-vectorizer.h
+++ b/gcc/tree-vectorizer.h
@@ -2636,7 +2636,7 @@ extern tree neutral_op_for_reduction (tree, code_helper, tree, bool = true);
 extern widest_int vect_iv_limit_for_partial_vectors (loop_vec_info loop_vinfo);
 bool vect_rgroup_iv_might_wrap_p (loop_vec_info, rgroup_controls *);
 /* Used in tree-vect-loop-manip.cc */
-extern opt_result vect_determine_partial_vectors_and_peeling (loop_vec_info);
+extern bool vect_need_peeling_or_partial_vectors_p (loop_vec_info);
 /* Used in gimple-loop-interchange.c and tree-parloops.cc.  */
 extern bool check_reduction_path (dump_user_location_t, loop_p, gphi *, tree,
 				  enum tree_code);