[PATCH] Don;t over allocate switch default clauses.

[Andrew MacLeod via Gcc-patches]

We were always allocating the 255 max ranges for the default 
condition.    Instead, use int_range_max to build the default range, 
then allocate and store only what is needed.

Bootstraps on  x86_64-pc-linux-gnu with no testsuite regressions.
Pushed.

Andrew


commit 57090307da6ff4378c84f768e2f2717095f712c1
Author: Andrew MacLeod <amacl...@redhat.com>
Date:   Mon Apr 26 17:50:18 2021 -0400

    Don't over-allocate switch default range object.
    
    We were always allocating the 255 max ranges for the default condition.
    Instead, use int_range_max to build the default range, then allocate and
    store only what is needed.
    
            * gimple-range-edge.cc (outgoing_range::calc_switch_ranges): Compute
            default range into a temp and allocate only what is needed.

diff --git a/gcc/gimple-range-edge.cc b/gcc/gimple-range-edge.cc
index d2c7d384dff..4d4cb97bbec 100644
--- a/gcc/gimple-range-edge.cc
+++ b/gcc/gimple-range-edge.cc
@@ -112,8 +112,7 @@ outgoing_range::calc_switch_ranges (gswitch *sw)
   //
   // Allocate an int_range_max for the default range case, start with
   // varying and intersect each other case from it.
-  irange *default_range = m_range_allocator.allocate (255);
-  default_range->set_varying (type);
+  int_range_max default_range (type);
 
   for (x = 1; x < lim; x++)
     {
@@ -132,7 +131,7 @@ outgoing_range::calc_switch_ranges (gswitch *sw)
       int_range_max def_range (low, high);
       range_cast (def_range, type);
       def_range.invert ();
-      default_range->intersect (def_range);
+      default_range.intersect (def_range);
 
       // Create/union this case with anything on else on the edge.
       int_range_max case_range (low, high);
@@ -156,7 +155,8 @@ outgoing_range::calc_switch_ranges (gswitch *sw)
   irange *&slot = m_edge_table->get_or_insert (default_edge, &existed);
   // This should be the first call into this switch.
   gcc_checking_assert (!existed);
-  slot = default_range;
+  irange *dr = m_range_allocator.allocate (default_range);
+  slot = dr;
 }