[gcc r13-1599] tree-optimization/106228 - fix vect_setup_realignment virtual SSA handling

[gcc r13-1599] tree-optimization/106228 - fix vect_setup_realignment virtual SSA handling

[Richard Biener]

https://gcc.gnu.org/g:79f18ac6b7ab7744fcf8937ea4bc0c40f3efc629

commit r13-1599-g79f18ac6b7ab7744fcf8937ea4bc0c40f3efc629
Author: Richard Biener <rguenther@suse.de>
Date:   Mon Jul 11 09:23:50 2022 +0200

    tree-optimization/106228 - fix vect_setup_realignment virtual SSA handling
    
    The following adds missing assignment of a virtual use operand to a
    created load to vect_setup_realignment which shows as bootstrap
    failure on powerpc64-linux and extra testsuite fails for targets
    when misaligned loads are not supported or not optimal.
    
            PR tree-optimization/106228
            * tree-vect-data-refs.cc (vect_setup_realignment): Properly
            set a VUSE operand on the emitted load.

Diff:
---
 gcc/tree-vect-data-refs.cc | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/gcc/tree-vect-data-refs.cc b/gcc/tree-vect-data-refs.cc
index d20a10a1524..53e52cb58cb 100644
--- a/gcc/tree-vect-data-refs.cc
+++ b/gcc/tree-vect-data-refs.cc
@@ -5780,6 +5780,13 @@ vect_setup_realignment (vec_info *vinfo, stmt_vec_info stmt_info,
   if (loop_for_initial_load)
     pe = loop_preheader_edge (loop_for_initial_load);
 
+  tree vuse;
+  gphi *vphi = get_virtual_phi (loop_for_initial_load->header);
+  if (vphi)
+    vuse = PHI_ARG_DEF_FROM_EDGE (vphi, pe);
+  else
+    vuse = gimple_vuse (gsi_stmt (*gsi));
+
   /* 3. For the case of the optimized realignment, create the first vector
       load at the loop preheader.  */
 
@@ -5813,6 +5820,7 @@ vect_setup_realignment (vec_info *vinfo, stmt_vec_info stmt_info,
       new_stmt = gimple_build_assign (vec_dest, data_ref);
       new_temp = make_ssa_name (vec_dest, new_stmt);
       gimple_assign_set_lhs (new_stmt, new_temp);
+      gimple_set_vuse (new_stmt, vuse);
       if (pe)
         {
           new_bb = gsi_insert_on_edge_immediate (pe, new_stmt);