[gcc r15-985] Avoid ICE with pointer reduction

[Richard Biener]

https://gcc.gnu.org/g:a1810364cd0c36d6408a4c386bdc504a021d68c7

commit r15-985-ga1810364cd0c36d6408a4c386bdc504a021d68c7
Author: Richard Biener <rguenther@suse.de>
Date:   Fri May 31 15:17:10 2024 +0200

    Avoid ICE with pointer reduction
    
    There's another case where we can refer to neutral_op before
    eventually converting it from pointer to integer so simply
    do that unconditionally.
    
            * tree-vect-loop.cc (get_initial_defs_for_reduction):
            Always convert neutral_op.

Diff:
---
 gcc/tree-vect-loop.cc | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc
index 5b85cffb37f..b6e0b9616d5 100644
--- a/gcc/tree-vect-loop.cc
+++ b/gcc/tree-vect-loop.cc
@@ -5606,6 +5606,12 @@ get_initial_defs_for_reduction (loop_vec_info loop_vinfo,
   tree_vector_builder elts (vector_type, nunits, 1);
   elts.quick_grow (nunits);
   gimple_seq ctor_seq = NULL;
+  if (neutral_op
+      && !useless_type_conversion_p (TREE_TYPE (vector_type),
+				     TREE_TYPE (neutral_op)))
+    neutral_op = gimple_convert (&ctor_seq,
+				 TREE_TYPE (vector_type),
+				 neutral_op);
   for (j = 0; j < nunits * number_of_vectors; ++j)
     {
       tree op;
@@ -5614,14 +5620,7 @@ get_initial_defs_for_reduction (loop_vec_info loop_vinfo,
       /* Get the def before the loop.  In reduction chain we have only
 	 one initial value.  Else we have as many as PHIs in the group.  */
       if (i >= initial_values.length () || (j > i && neutral_op))
-	{
-	  if (!useless_type_conversion_p (TREE_TYPE (vector_type),
-					  TREE_TYPE (neutral_op)))
-	    neutral_op = gimple_convert (&ctor_seq,
-					 TREE_TYPE (vector_type),
-					 neutral_op);
-	  op = neutral_op;
-	}
+	op = neutral_op;
       else
 	{
 	  if (!useless_type_conversion_p (TREE_TYPE (vector_type),