[PATCH]middle-end slp: elide intermediate nodes for complex add and avoid truncate

[Tamar Christina via Gcc-patches]

Hi All,

This applies the same feedback received for MUL and the rest to
ADD which was already committed.  In short it elides the intermediate
nodes vec and avoids the use of truncate on the SLP child.

Bootstrapped Regtested on aarch64-none-linux-gnu and no issues.

Ok for master?

Thanks,
Tamar

gcc/ChangeLog:

        * tree-vect-slp-patterns.c (complex_add_pattern::build):

--- inline copy of patch -- 
diff --git a/gcc/tree-vect-slp-patterns.c b/gcc/tree-vect-slp-patterns.c
index 
be066b08310b72320fdbeb88a6b2969151f73cdc..e9f70958fdc32427ab0e1cceadfed41dfa091b47
 100644
--- a/gcc/tree-vect-slp-patterns.c
+++ b/gcc/tree-vect-slp-patterns.c
@@ -645,23 +645,21 @@ class complex_add_pattern : public complex_pattern
 void
 complex_add_pattern::build (vec_info *vinfo)
 {
-  auto_vec<slp_tree> nodes;
+  SLP_TREE_CHILDREN (*this->m_node).reserve_exact (2);
+
   slp_tree node = this->m_ops[0];
   vec<slp_tree> children = SLP_TREE_CHILDREN (node);
 
   /* First re-arrange the children.  */
-  nodes.create (children.length ());
-  nodes.quick_push (children[0]);
-  nodes.quick_push (vect_build_swap_evenodd_node (children[1]));
+  SLP_TREE_CHILDREN (*this->m_node)[0] = children[0];
+  SLP_TREE_CHILDREN (*this->m_node)[1] =
+    vect_build_swap_evenodd_node (children[1]);
 
-  SLP_TREE_REF_COUNT (nodes[0])++;
-  SLP_TREE_REF_COUNT (nodes[1])++;
+  SLP_TREE_REF_COUNT (SLP_TREE_CHILDREN (*this->m_node)[0])++;
+  SLP_TREE_REF_COUNT (SLP_TREE_CHILDREN (*this->m_node)[1])++;
   vect_free_slp_tree (this->m_ops[0]);
   vect_free_slp_tree (this->m_ops[1]);
 
-  SLP_TREE_CHILDREN (*this->m_node).truncate (0);
-  SLP_TREE_CHILDREN (*this->m_node).safe_splice (nodes);
-
   complex_pattern::build (vinfo);
 }
 


-- 

diff --git a/gcc/tree-vect-slp-patterns.c b/gcc/tree-vect-slp-patterns.c
index be066b08310b72320fdbeb88a6b2969151f73cdc..e9f70958fdc32427ab0e1cceadfed41dfa091b47 100644
--- a/gcc/tree-vect-slp-patterns.c
+++ b/gcc/tree-vect-slp-patterns.c
@@ -645,23 +645,21 @@ class complex_add_pattern : public complex_pattern
 void
 complex_add_pattern::build (vec_info *vinfo)
 {
-  auto_vec<slp_tree> nodes;
+  SLP_TREE_CHILDREN (*this->m_node).reserve_exact (2);
+
   slp_tree node = this->m_ops[0];
   vec<slp_tree> children = SLP_TREE_CHILDREN (node);
 
   /* First re-arrange the children.  */
-  nodes.create (children.length ());
-  nodes.quick_push (children[0]);
-  nodes.quick_push (vect_build_swap_evenodd_node (children[1]));
+  SLP_TREE_CHILDREN (*this->m_node)[0] = children[0];
+  SLP_TREE_CHILDREN (*this->m_node)[1] =
+    vect_build_swap_evenodd_node (children[1]);
 
-  SLP_TREE_REF_COUNT (nodes[0])++;
-  SLP_TREE_REF_COUNT (nodes[1])++;
+  SLP_TREE_REF_COUNT (SLP_TREE_CHILDREN (*this->m_node)[0])++;
+  SLP_TREE_REF_COUNT (SLP_TREE_CHILDREN (*this->m_node)[1])++;
   vect_free_slp_tree (this->m_ops[0]);
   vect_free_slp_tree (this->m_ops[1]);
 
-  SLP_TREE_CHILDREN (*this->m_node).truncate (0);
-  SLP_TREE_CHILDREN (*this->m_node).safe_splice (nodes);
-
   complex_pattern::build (vinfo);
 }