[gcc r12-7658] analyzer: presize m_cluster_map in store copy ctor

[gcc r12-7658] analyzer: presize m_cluster_map in store copy ctor

[David Malcolm]

https://gcc.gnu.org/g:a58e342d8869c571476c76d0ed95488adbde26bd

commit r12-7658-ga58e342d8869c571476c76d0ed95488adbde26bd
Author: David Malcolm <dmalcolm@redhat.com>
Date:   Tue Mar 15 17:55:14 2022 -0400

    analyzer: presize m_cluster_map in store copy ctor
    
    Testing cc1 on pr93032-mztools-unsigned-char.c
    
    Benchmark #1: (without patch)
      Time (mean ± σ):     338.8 ms ±  13.6 ms    [User: 323.2 ms, System: 14.2 ms]
      Range (min … max):   326.7 ms … 363.1 ms    10 runs
    
    Benchmark #2: (with patch)
      Time (mean ± σ):     332.3 ms ±  12.8 ms    [User: 316.6 ms, System: 14.3 ms]
      Range (min … max):   322.5 ms … 357.4 ms    10 runs
    
    Summary
      ./cc1.new ran 1.02 ± 0.06 times faster than ./cc1.old
    
    gcc/analyzer/ChangeLog:
            * store.cc (store::store): Presize m_cluster_map.
    
    Signed-off-by: David Malcolm <dmalcolm@redhat.com>

Diff:
---
 gcc/analyzer/store.cc | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/gcc/analyzer/store.cc b/gcc/analyzer/store.cc
index 58df7aab8a2..ec11433dffc 100644
--- a/gcc/analyzer/store.cc
+++ b/gcc/analyzer/store.cc
@@ -2032,7 +2032,8 @@ store::store ()
 /* store's copy ctor.  */
 
 store::store (const store &other)
-: m_called_unknown_fn (other.m_called_unknown_fn)
+: m_cluster_map (other.m_cluster_map.elements ()),
+  m_called_unknown_fn (other.m_called_unknown_fn)
 {
   for (cluster_map_t::iterator iter = other.m_cluster_map.begin ();
        iter != other.m_cluster_map.end ();