path solver: Adjustments for use outside of the backward threader.

Here are some enhancements to make it easier for other clients to use
the path solver.

First, I've made the imports to the solver optional since we can
calculate them ourselves.  However, I've left the ability to set them,
since the backward threader adds a few SSA names in addition to the
default ones.  As a follow-up I may move all the import set up code
from the threader to the solver, as the extra imports tend to improve
the behavior slightly.

Second, Richi suggested an entry point where you just feed the solver
an edge, which will be quite convenient for a subsequent patch adding
a client in the header copying pass.  The required some shuffling,
since we'll be adding the blocks on the fly.  There's now a vector
copy, but the impact will be minimal, since these are just 5-6 entries
at the most.

Tested on ppc64le Linux.

gcc/ChangeLog:

	* gimple-range-path.cc (path_range_query::path_range_query): Do
	not init m_path.
	(path_range_query::dump): Change m_path uses to non-pointer.
	(path_range_query::defined_outside_path):  Same.
	(path_range_query::set_path): Same.
	(path_range_query::add_copies_to_imports): Same.
	(path_range_query::range_of_stmt): Same.
	(path_range_query::compute_outgoing_relations): Same.
	(path_range_query::compute_ranges): Imports are now optional.
	Implement overload that takes an edge.
	* gimple-range-path.h (class path_range_query): Make imports
	optional for compute_ranges.  Add compute_ranges(edge) overload.
	Make m_path an auto_vec instead of a pointer and adjust
	accordingly.

1 files changed, 30 insertions, 11 deletions

diff --git a/gcc/gimple-range-path.cc b/gcc/gimple-range-path.cc
index 99ac947..6da01c7 100644
--- a/gcc/gimple-range-path.cc
+++ b/gcc/gimple-range-path.cc
@@ -41,7 +41,6 @@ path_range_query::path_range_query (gimple_ranger &ranger, bool resolve)
 {
   m_cache = new ssa_global_cache;
   m_has_cache_entry = BITMAP_ALLOC (NULL);
-  m_path = NULL;
   m_resolve = resolve;
   m_oracle = new path_oracle (ranger.oracle ());
 }
@@ -92,13 +91,13 @@ path_range_query::dump (FILE *dump_file)
 {
   push_dump_file save (dump_file, dump_flags & ~TDF_DETAILS);
 
-  if (m_path->is_empty ())
+  if (m_path.is_empty ())
     return;
 
   unsigned i;
   bitmap_iterator bi;
 
-  dump_ranger (dump_file, *m_path);
+  dump_ranger (dump_file, m_path);
 
   fprintf (dump_file, "Imports:\n");
   EXECUTE_IF_SET_IN_BITMAP (m_imports, 0, i, bi)
@@ -125,7 +124,7 @@ path_range_query::defined_outside_path (tree name)
   gimple *def = SSA_NAME_DEF_STMT (name);
   basic_block bb = gimple_bb (def);
 
-  return !bb || !m_path->contains (bb);
+  return !bb || !m_path.contains (bb);
 }
 
 // Return the range of NAME on entry to the path.
@@ -230,8 +229,8 @@ void
 path_range_query::set_path (const vec<basic_block> &path)
 {
   gcc_checking_assert (path.length () > 1);
-  m_path = &path;
-  m_pos = m_path->length () - 1;
+  m_path = path.copy ();
+  m_pos = m_path.length () - 1;
   bitmap_clear (m_has_cache_entry);
 }
 
@@ -486,7 +485,7 @@ path_range_query::add_copies_to_imports ()
 	      tree arg = gimple_phi_arg (phi, i)->def;
 
 	      if (TREE_CODE (arg) == SSA_NAME
-		  && m_path->contains (e->src)
+		  && m_path.contains (e->src)
 		  && bitmap_set_bit (m_imports, SSA_NAME_VERSION (arg)))
 		worklist.safe_push (arg);
 	    }
@@ -497,7 +496,8 @@ path_range_query::add_copies_to_imports ()
 // Compute the ranges for IMPORTS along PATH.
 //
 // IMPORTS are the set of SSA names, any of which could potentially
-// change the value of the final conditional in PATH.
+// change the value of the final conditional in PATH.  Default to the
+// imports of the last block in the path if none is given.
 
 void
 path_range_query::compute_ranges (const vec<basic_block> &path,
@@ -507,9 +507,16 @@ path_range_query::compute_ranges (const vec<basic_block> &path,
     fprintf (dump_file, "\n==============================================\n");
 
   set_path (path);
-  bitmap_copy (m_imports, imports);
   m_undefined_path = false;
 
+  if (imports)
+    bitmap_copy (m_imports, imports);
+  else
+    {
+      bitmap imports = m_ranger.gori ().imports (exit_bb ());
+      bitmap_copy (m_imports, imports);
+    }
+
   if (m_resolve)
     {
       add_copies_to_imports ();
@@ -561,6 +568,18 @@ path_range_query::compute_ranges (const vec<basic_block> &path,
     }
 }
 
+// Convenience function to compute ranges along a path consisting of
+// E->SRC and E->DEST.
+
+void
+path_range_query::compute_ranges (edge e)
+{
+  auto_vec<basic_block> bbs (2);
+  bbs.quick_push (e->dest);
+  bbs.quick_push (e->src);
+  compute_ranges (bbs);
+}
+
 // A folding aid used to register and query relations along a path.
 // When queried, it returns relations as they would appear on exit to
 // the path.
@@ -643,7 +662,7 @@ path_range_query::range_of_stmt (irange &r, gimple *stmt, tree)
   if (m_resolve)
     {
       fold_using_range f;
-      jt_fur_source src (stmt, this, &m_ranger.gori (), *m_path);
+      jt_fur_source src (stmt, this, &m_ranger.gori (), m_path);
       if (!f.fold_stmt (r, stmt, src))
 	r.set_varying (type);
     }
@@ -734,7 +753,7 @@ path_range_query::compute_outgoing_relations (basic_block bb, basic_block next)
       else
 	gcc_unreachable ();
 
-      jt_fur_source src (NULL, this, &m_ranger.gori (), *m_path);
+      jt_fur_source src (NULL, this, &m_ranger.gori (), m_path);
       src.register_outgoing_edges (cond, r, e0, e1);
     }
 }