re PR middle-end/54146 (Very slow compile with attribute((flatten)))

[thirdparty/gcc.git] / gcc / tree-into-ssa.c

diff --git a/gcc/tree-into-ssa.c b/gcc/tree-into-ssa.c
index 073a4881a6284e7f6b331bd7747e8a92163f1206..a3c31799d02497a3425d7b4c21e5b94c98e5195c 100644 (file)
--- a/gcc/tree-into-ssa.c
+++ b/gcc/tree-into-ssa.c
@@ -312,22 +312,21 @@ get_ssa_name_ann (tree name)
   unsigned len = VEC_length (ssa_name_info_p, info_for_ssa_name);
   struct ssa_name_info *info;
 
+  /* Re-allocate the vector at most once per update/into-SSA.  */
   if (ver >= len)
-    {
-      unsigned old_len = VEC_length (ssa_name_info_p, info_for_ssa_name);
-      unsigned new_len = num_ssa_names;
+    VEC_safe_grow_cleared (ssa_name_info_p, heap,
+                          info_for_ssa_name, num_ssa_names);
 
-      VEC_reserve (ssa_name_info_p, heap, info_for_ssa_name,
-                  new_len - old_len);
-      while (len++ < new_len)
-       {
-         struct ssa_name_info *info = XCNEW (struct ssa_name_info);
-         info->age = current_info_for_ssa_name_age;
-         VEC_quick_push (ssa_name_info_p, info_for_ssa_name, info);
-       }
+  /* But allocate infos lazily.  */
+  info = VEC_index (ssa_name_info_p, info_for_ssa_name, ver);
+  if (!info)
+    {
+      info = XCNEW (struct ssa_name_info);
+      info->age = current_info_for_ssa_name_age;
+      info->info.need_phi_state = NEED_PHI_STATE_UNKNOWN;
+      VEC_replace (ssa_name_info_p, info_for_ssa_name, ver, info);
     }
 
-  info = VEC_index (ssa_name_info_p, info_for_ssa_name, ver);
   if (info->age < current_info_for_ssa_name_age)
     {
       info->age = current_info_for_ssa_name_age;