[gcc r12-1769] Fix SLP permute propagation error

[Richard Biener]

https://gcc.gnu.org/g:82ab14927651e0eaf0f6d6964396048bb5471f23

commit r12-1769-g82ab14927651e0eaf0f6d6964396048bb5471f23
Author: Richard Biener <rguenther@suse.de>
Date:   Thu Jun 24 10:47:18 2021 +0200

    Fix SLP permute propagation error
    
    This fixes SLP permute propagation to not propagate across operations
    that have different semantics on different lanes like for example
    the recently added COMPLEX_ADD_ROT90.
    
    2021-06-24  Richard Biener  <rguenther@suse.de>
    
            * tree-vect-slp.c (vect_optimize_slp): Do not propagate
            across operations that have different semantics on different
            lanes.

Diff:
---
 gcc/tree-vect-slp.c | 30 +++++++++++++++++++++++-------
 1 file changed, 23 insertions(+), 7 deletions(-)

diff --git a/gcc/tree-vect-slp.c b/gcc/tree-vect-slp.c
index 29db56ed532..69ee8faed09 100644
--- a/gcc/tree-vect-slp.c
+++ b/gcc/tree-vect-slp.c
@@ -3680,18 +3680,34 @@ vect_optimize_slp (vec_info *vinfo)
 	{
 	  int idx = ipo[i-1];
 	  slp_tree node = vertices[idx].node;
-	  /* For leafs there's nothing to do - we've seeded permutes
-	     on those above.  */
-	  if (SLP_TREE_DEF_TYPE (node) != vect_internal_def)
+
+	  /* Handle externals and constants optimistically throughout the
+	     iteration.  */
+	  if (SLP_TREE_DEF_TYPE (node) == vect_external_def
+	      || SLP_TREE_DEF_TYPE (node) == vect_constant_def)
 	    continue;
 
 	  vertices[idx].visited = 1;
 
-	  /* We cannot move a permute across a store.  */
-	  if (STMT_VINFO_DATA_REF (SLP_TREE_REPRESENTATIVE (node))
-	      && DR_IS_WRITE
-		   (STMT_VINFO_DATA_REF (SLP_TREE_REPRESENTATIVE (node))))
+	  /* We do not handle stores with a permutation.  */
+	  stmt_vec_info rep = SLP_TREE_REPRESENTATIVE (node);
+	  if (STMT_VINFO_DATA_REF (rep)
+	      && DR_IS_WRITE (STMT_VINFO_DATA_REF (rep)))
 	    continue;
+	  /* We cannot move a permute across an operation that is
+	     not independent on lanes.  Note this is an explicit
+	     negative list since that's much shorter than the respective
+	     positive one but it's critical to keep maintaining it.  */
+	  if (is_gimple_call (STMT_VINFO_STMT (rep)))
+	    switch (gimple_call_combined_fn (STMT_VINFO_STMT (rep)))
+	      {
+	      case CFN_COMPLEX_ADD_ROT90:
+	      case CFN_COMPLEX_ADD_ROT270:
+	      case CFN_COMPLEX_MUL:
+	      case CFN_COMPLEX_MUL_CONJ:
+		continue;
+	      default:;
+	      }
 
 	  int perm = -1;
 	  for (graph_edge *succ = slpg->vertices[idx].succ;