[gcc r12-4903] path solver: Only compute relations for imports.

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

https://gcc.gnu.org/g:5ea1ce43b6070aaa94882e8b15f3340344aaa6b2

commit r12-4903-g5ea1ce43b6070aaa94882e8b15f3340344aaa6b2
Author: Aldy Hernandez <aldyh@redhat.com>
Date:   Wed Nov 3 08:23:25 2021 +0100

    path solver: Only compute relations for imports.
    
    We are currently calculating implicit PHI relations for all PHI
    arguments.  This creates unecessary work, as we only care about SSA
    names in the import bitmap.  Similarly for inter-path relationals.  We
    can avoid things not in the bitmap.
    
    Tested on x86-64 and ppc64le Linux with the usual regstrap.  I also
    verified that the before and after number of threads was the same
    in a suite of .ii files from a bootstrap.
    
    gcc/ChangeLog:
    
            PR tree-optimization/102943
            * gimple-range-path.cc (path_range_query::compute_phi_relations):
            Only compute relations for SSA names in the import list.
            (path_range_query::compute_outgoing_relations): Same.
            * gimple-range-path.h (path_range_query::import_p): New.

Diff:
---
 gcc/gimple-range-path.cc |  7 ++++++-
 gcc/gimple-range-path.h  | 10 ++++++++++
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/gcc/gimple-range-path.cc b/gcc/gimple-range-path.cc
index d8c2a9b6a86..42309886c94 100644
--- a/gcc/gimple-range-path.cc
+++ b/gcc/gimple-range-path.cc
@@ -678,8 +678,12 @@ path_range_query::compute_phi_relations (basic_block bb, basic_block prev)
        gsi_next (&iter))
     {
       gphi *phi = iter.phi ();
+      tree result = gimple_phi_result (phi);
       unsigned nargs = gimple_phi_num_args (phi);
 
+      if (!import_p (result))
+	continue;
+
       for (size_t i = 0; i < nargs; ++i)
 	if (e_in == gimple_phi_arg_edge (phi, i))
 	  {
@@ -701,7 +705,8 @@ path_range_query::compute_outgoing_relations (basic_block bb, basic_block next)
 
   if (stmt
       && gimple_code (stmt) == GIMPLE_COND
-      && irange::supports_type_p (TREE_TYPE (gimple_cond_lhs (stmt))))
+      && (import_p (gimple_cond_lhs (stmt))
+	  || import_p (gimple_cond_rhs (stmt))))
     {
       int_range<2> r;
       gcond *cond = as_a<gcond *> (stmt);
diff --git a/gcc/gimple-range-path.h b/gcc/gimple-range-path.h
index 541613956e1..f21d07f71c4 100644
--- a/gcc/gimple-range-path.h
+++ b/gcc/gimple-range-path.h
@@ -62,6 +62,7 @@ private:
   void maybe_register_phi_relation (gphi *, tree arg);
   void add_copies_to_imports ();
   bool add_to_imports (tree name, bitmap imports);
+  inline bool import_p (tree name);
 
   // Path navigation.
   void set_path (const vec<basic_block> &);
@@ -97,4 +98,13 @@ private:
   bool m_undefined_path;
 };
 
+// Return TRUE if NAME is in the import bitmap.
+
+bool
+path_range_query::import_p (tree name)
+{
+  return (TREE_CODE (name) == SSA_NAME
+	  && bitmap_bit_p (m_imports, SSA_NAME_VERSION (name)));
+}
+
 #endif // GCC_TREE_SSA_THREADSOLVER_H