path solver: Compute ranges in path in gimple order.

Andrew's patch for this PR103254 papered over some underlying
performance issues in the path solver that I'd like to address.

We are currently solving the SSA's defined in the current block in
bitmap order, which amounts to random order for all purposes.  This is
causing unnecessary recursion in gori.  This patch changes the order
to gimple order, thus solving dependencies before uses.

There is no change in threadable paths with this change.

Tested on x86-64 & ppc64le Linux.

gcc/ChangeLog:

	PR tree-optimization/103254
	* gimple-range-path.cc (path_range_query::compute_ranges_defined): New
	(path_range_query::compute_ranges_in_block): Move to
	compute_ranges_defined.
	* gimple-range-path.h (compute_ranges_defined): New.

1 files changed, 22 insertions, 11 deletions

diff --git a/gcc/gimple-range-path.cc b/gcc/gimple-range-path.cc
index 4aa666d..e240866 100644
--- a/gcc/gimple-range-path.cc
+++ b/gcc/gimple-range-path.cc
@@ -401,6 +401,27 @@ path_range_query::compute_ranges_in_phis (basic_block bb)
     }
 }
 
+// Compute ranges defined in block.
+
+void
+path_range_query::compute_ranges_defined (basic_block bb)
+{
+  int_range_max r;
+
+  compute_ranges_in_phis (bb);
+
+  // Iterate in gimple order to minimize recursion.
+  for (auto gsi = gsi_start_nondebug_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
+    if (gimple_has_lhs (gsi_stmt (gsi)))
+      {
+	tree name = gimple_get_lhs (gsi_stmt (gsi));
+	if (TREE_CODE (name) == SSA_NAME
+	    && bitmap_bit_p (m_imports, SSA_NAME_VERSION (name))
+	    && range_defined_in_block (r, name, bb))
+	  set_cache (r, name);
+      }
+}
+
 // Compute ranges defined in the current block, or exported to the
 // next block.
 
@@ -423,17 +444,7 @@ path_range_query::compute_ranges_in_block (basic_block bb)
 	clear_cache (name);
     }
 
-  // Solve imports defined in this block, starting with the PHIs...
-  compute_ranges_in_phis (bb);
-  // ...and then the rest of the imports.
-  EXECUTE_IF_SET_IN_BITMAP (m_imports, 0, i, bi)
-    {
-      tree name = ssa_name (i);
-
-      if (gimple_code (SSA_NAME_DEF_STMT (name)) != GIMPLE_PHI
-	  && range_defined_in_block (r, name, bb))
-	set_cache (r, name);
-    }
+  compute_ranges_defined (bb);
 
   if (at_exit ())
     return;