[PATCH] tree-optimization/97098 - fix compile-time hog in SLP live

[Richard Biener]

This fixes a missed early-out in SLP live stmt marking when
all scalar stmts were already visited (oops).

Bootstrapped on x86_64-unknown-linux-gnu, testing in progress.

2020-09-18  Richard Biener  <rguent...@suse.de>

        PR tree-optimization/97098
        * tree-vect-slp.c (vect_bb_slp_mark_live_stmts): Do not
        recurse to children when all stmts were already visited.
---
 gcc/tree-vect-slp.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/gcc/tree-vect-slp.c b/gcc/tree-vect-slp.c
index ecce7a982dd..ef62c2dff2e 100644
--- a/gcc/tree-vect-slp.c
+++ b/gcc/tree-vect-slp.c
@@ -3018,11 +3018,13 @@ vect_bb_slp_mark_live_stmts (bb_vec_info bb_vinfo, 
slp_tree node,
   unsigned i;
   stmt_vec_info stmt_info;
   stmt_vec_info last_stmt = vect_find_last_scalar_stmt_in_slp (node);
+  bool all_visited = true;
   FOR_EACH_VEC_ELT (SLP_TREE_SCALAR_STMTS (node), i, stmt_info)
     {
       stmt_vec_info orig_stmt_info = vect_orig_stmt (stmt_info);
       if (svisited.contains (orig_stmt_info))
        continue;
+      all_visited = false;
       bool mark_visited = true;
       gimple *orig_stmt = orig_stmt_info->stmt;
       ssa_op_iter op_iter;
@@ -3091,6 +3093,8 @@ vect_bb_slp_mark_live_stmts (bb_vec_info bb_vinfo, 
slp_tree node,
       if (mark_visited)
        svisited.add (orig_stmt_info);
     }
+  if (all_visited)
+    return;
 
   slp_tree child;
   FOR_EACH_VEC_ELT (SLP_TREE_CHILDREN (node), i, child)
-- 
2.26.2