[gcc r12-5128] Grow sbr_vector in ranger's on-entry cache as needed.

[Aldy Hernandez <aldyh@gcc.gnu.org>]

https://gcc.gnu.org/g:eaec20fde587e0695b100dcba5ff56944c3ae8c0

commit r12-5128-geaec20fde587e0695b100dcba5ff56944c3ae8c0
Author: Andrew MacLeod <amacleod@redhat.com>
Date:   Wed Nov 10 16:49:50 2021 +0100

    Grow sbr_vector in ranger's on-entry cache as needed.
    
    The on-entry cache does not expect the number of BBs to change.  This
    could happen in various scenarios, recently in the suggestion to use
    ranger with loop unswitching and also with a work in progress to use
    the path solver in the loopch pass.  This patch fixes both.
    
    This is a patch from Andrew, who tested it on x86-64 Linux.
    
    gcc/ChangeLog:
    
            * gimple-range-cache.cc (sbr_vector::grow): New.
            (sbr_vector::set_bb_range): Call grow.
            (sbr_vector::get_bb_range): Same.
            (sbr_vector::bb_range_p): Remove assert.

Diff:
---
 gcc/gimple-range-cache.cc | 35 +++++++++++++++++++++++++++++++----
 1 file changed, 31 insertions(+), 4 deletions(-)

diff --git a/gcc/gimple-range-cache.cc b/gcc/gimple-range-cache.cc
index e5591bab0ef..a63e20e7e49 100644
--- a/gcc/gimple-range-cache.cc
+++ b/gcc/gimple-range-cache.cc
@@ -210,6 +210,7 @@ protected:
   int_range<2> m_undefined;
   tree m_type;
   irange_allocator *m_irange_allocator;
+  void grow ();
 };
 
 
@@ -229,13 +230,37 @@ sbr_vector::sbr_vector (tree t, irange_allocator *allocator)
   m_undefined.set_undefined ();
 }
 
+// Grow the vector when the CFG has increased in size.
+
+void
+sbr_vector::grow ()
+{
+  int curr_bb_size = last_basic_block_for_fn (cfun);
+  gcc_checking_assert (curr_bb_size > m_tab_size);
+
+  // Increase the max of a)128, b)needed increase * 2, c)10% of current_size.
+  int inc = MAX ((curr_bb_size - m_tab_size) * 2, 128);
+  inc = MAX (inc, curr_bb_size / 10);
+  int new_size = inc + curr_bb_size;
+
+  // Allocate new memory, copy the old vector and clear the new space.
+  irange **t = (irange **)m_irange_allocator->get_memory (new_size
+							  * sizeof (irange *));
+  memcpy (t, m_tab, m_tab_size * sizeof (irange *));
+  memset (t + m_tab_size, 0, (new_size - m_tab_size) * sizeof (irange *));
+
+  m_tab = t;
+  m_tab_size = new_size;
+}
+
 // Set the range for block BB to be R.
 
 bool
 sbr_vector::set_bb_range (const_basic_block bb, const irange &r)
 {
   irange *m;
-  gcc_checking_assert (bb->index < m_tab_size);
+  if (bb->index >= m_tab_size)
+    grow ();
   if (r.varying_p ())
     m = &m_varying;
   else if (r.undefined_p ())
@@ -252,7 +277,8 @@ sbr_vector::set_bb_range (const_basic_block bb, const irange &r)
 bool
 sbr_vector::get_bb_range (irange &r, const_basic_block bb)
 {
-  gcc_checking_assert (bb->index < m_tab_size);
+  if (bb->index >= m_tab_size)
+    return false;
   irange *m = m_tab[bb->index];
   if (m)
     {
@@ -267,8 +293,9 @@ sbr_vector::get_bb_range (irange &r, const_basic_block bb)
 bool
 sbr_vector::bb_range_p (const_basic_block bb)
 {
-  gcc_checking_assert (bb->index < m_tab_size);
-  return m_tab[bb->index] != NULL;
+  if (bb->index < m_tab_size)
+    return m_tab[bb->index] != NULL;
+  return false;
 }
 
 // This class implements the on entry cache via a sparse bitmap.