[COMMITTED] Use non-null knowledge in path_range_query.

[Aldy Hernandez <aldyh@redhat.com>]

[Jeff, I'm CCing you to keep you in the loop on changes that will impact
jump threading.  Since we're using one engine, any changes to the either
ranger or the path solver, is likely to improve jump threading.]

This patch improves ranges for pointers we are interested in a path, by
using the non-null class from the ranger.  This allows us to thread more
paths with minimal effort.

Tested on x86-64 Linux.

gcc/ChangeLog:

	* gimple-range-path.cc (path_range_query::range_defined_in_block):
	Adjust for non-null.
	(path_range_query::adjust_for_non_null_uses): New.
	(path_range_query::precompute_ranges): Call
	adjust_for_non_null_uses.
	* gimple-range-path.h: Add m_non_null and
	adjust_for_non_null_uses.
---
 gcc/gimple-range-path.cc | 33 +++++++++++++++++++++++++++++++++
 gcc/gimple-range-path.h  |  2 ++
 2 files changed, 35 insertions(+)

diff --git a/gcc/gimple-range-path.cc b/gcc/gimple-range-path.cc
index 6d6e5eb6635..db15eb3ff22 100644
--- a/gcc/gimple-range-path.cc
+++ b/gcc/gimple-range-path.cc
@@ -221,6 +221,9 @@ path_range_query::range_defined_in_block (irange &r, tree name, basic_block bb)
   else if (!fold_range (r, def_stmt, this))
     r.set_varying (TREE_TYPE (name));
 
+  if (bb)
+    m_non_null.adjust_range (r, name, bb);
+
   if (DEBUG_SOLVER && (bb || !r.varying_p ()))
     {
       fprintf (dump_file, "range_defined_in_block (BB%d) for ", bb ? bb->index : -1);
@@ -302,6 +305,35 @@ path_range_query::precompute_ranges_in_block (basic_block bb)
     }
 }
 
+// Adjust all pointer imports in BB with non-null information.
+
+void
+path_range_query::adjust_for_non_null_uses (basic_block bb)
+{
+  int_range_max r;
+  bitmap_iterator bi;
+  unsigned i;
+
+  EXECUTE_IF_SET_IN_BITMAP (m_imports, 0, i, bi)
+    {
+      tree name = ssa_name (i);
+
+      if (!POINTER_TYPE_P (TREE_TYPE (name)))
+	continue;
+
+      if (get_cache (r, name))
+	{
+	  if (r.nonzero_p ())
+	    continue;
+	}
+      else
+	r.set_varying (TREE_TYPE (name));
+
+      if (m_non_null.adjust_range (r, name, bb))
+	set_cache (r, name);
+    }
+}
+
 // Precompute the ranges for IMPORTS along PATH.
 //
 // IMPORTS are the set of SSA names, any of which could potentially
@@ -332,6 +364,7 @@ path_range_query::precompute_ranges (const vec<basic_block> &path,
       basic_block bb = curr_bb ();
 
       precompute_ranges_in_block (bb);
+      adjust_for_non_null_uses (bb);
 
       if (at_exit ())
 	break;
diff --git a/gcc/gimple-range-path.h b/gcc/gimple-range-path.h
index 0d2d2e7f75d..51773131040 100644
--- a/gcc/gimple-range-path.h
+++ b/gcc/gimple-range-path.h
@@ -53,6 +53,7 @@ private:
   // Methods to precompute ranges for the given path.
   bool range_defined_in_block (irange &, tree name, basic_block bb);
   void precompute_ranges_in_block (basic_block bb);
+  void adjust_for_non_null_uses (basic_block bb);
   void ssa_range_in_phi (irange &r, gphi *phi);
 
   // Path navigation.
@@ -80,6 +81,7 @@ private:
 
   const bitmap_head *m_imports;
   gimple_ranger &m_ranger;
+  non_null_ref m_non_null;
 };
 
 #endif // GCC_TREE_SSA_THREADSOLVER_H
-- 
2.31.1