[PATCH][RFC] Add gimple-cfg.h.

[Martin Liška <mliska at suse dot cz>]

Hi.

I'm considering adding couple of new gimple-related functions that
are related to gswitch statement.

Is it a good idea?
Martin

gcc/ChangeLog:

2018-08-06  Martin Liska  <mliska@suse.cz>

	* gimple-cfg.h: New file.
	* ipa-fnsummary.c (set_switch_stmt_execution_predicate):
        Use gimple_switch_edge (and gimple_switch_default_edge).
	* tree-switch-conversion.c (switch_conversion::collect): Likewise.
	(switch_decision_tree::compute_cases_per_edge): Likewise.
	(switch_decision_tree::analyze_switch_statement): Likewise.
	(switch_decision_tree::try_switch_expansion): Likewise.
---
 gcc/gimple-cfg.h             | 44 ++++++++++++++++++++++++++++++++++++
 gcc/ipa-fnsummary.c          |  7 +++---
 gcc/tree-switch-conversion.c | 38 ++++++++++++-------------------
 3 files changed, 62 insertions(+), 27 deletions(-)
 create mode 100644 gcc/gimple-cfg.h


diff --git a/gcc/gimple-cfg.h b/gcc/gimple-cfg.h
new file mode 100644
index 00000000000..1e95338bede
--- /dev/null
+++ b/gcc/gimple-cfg.h
@@ -0,0 +1,44 @@
+/* Gimple IR definitions related to CFG.
+
+   Copyright (C) 2007-2018 Free Software Foundation, Inc.
+   Contributed by Martin Liska <mliska@suse.cz>
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3.  If not see
+<http://www.gnu.org/licenses/>.  */
+
+#ifndef GCC_GIMPLE_CFG_H
+#define GCC_GIMPLE_CFG_H
+
+/* Return the edge that belongs to label numbered INDEX
+   of a switch statement.  */
+
+static inline edge
+gimple_switch_edge (gswitch *gs, unsigned index)
+{
+  tree label = CASE_LABEL (gimple_switch_label (gs, index));
+  return find_edge (gimple_bb (gs), label_to_block (label));
+}
+
+/* Return the default edge of a switch statement.  */
+
+static inline edge
+gimple_switch_default_edge (gswitch *gs)
+{
+  tree label = CASE_LABEL (gimple_switch_label (gs, 0));
+  return find_edge (gimple_bb (gs), label_to_block (label));
+}
+
+#endif  /* GCC_GIMPLE_CFG_H */
diff --git a/gcc/ipa-fnsummary.c b/gcc/ipa-fnsummary.c
index a8fc2c2df9a..2991e647fc4 100644
--- a/gcc/ipa-fnsummary.c
+++ b/gcc/ipa-fnsummary.c
@@ -56,7 +56,10 @@ along with GCC; see the file COPYING3.  If not see
 #include "coretypes.h"
 #include "backend.h"
 #include "tree.h"
+#include "cfganal.h"
 #include "gimple.h"
+#include "tree-cfg.h"
+#include "gimple-cfg.h"
 #include "alloc-pool.h"
 #include "tree-pass.h"
 #include "ssa.h"
@@ -68,9 +71,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "tree-inline.h"
 #include "gimple-pretty-print.h"
 #include "params.h"
-#include "cfganal.h"
 #include "gimple-iterator.h"
-#include "tree-cfg.h"
 #include "tree-ssa-loop-niter.h"
 #include "tree-ssa-loop.h"
 #include "symbol-summary.h"
@@ -1291,7 +1292,7 @@ set_switch_stmt_execution_predicate (struct ipa_func_body_info *fbi,
       tree min, max;
       predicate p;
 
-      e = find_edge (bb, label_to_block (CASE_LABEL (cl)));
+      e = gimple_switch_edge (last, case_idx);
       min = CASE_LOW (cl);
       max = CASE_HIGH (cl);
 
diff --git a/gcc/tree-switch-conversion.c b/gcc/tree-switch-conversion.c
index 9a594a01fc4..492cd365a30 100644
--- a/gcc/tree-switch-conversion.c
+++ b/gcc/tree-switch-conversion.c
@@ -29,6 +29,8 @@ Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
 #include "insn-codes.h"
 #include "rtl.h"
 #include "tree.h"
+#include "cfganal.h"
+#include "tree-cfg.h"
 #include "gimple.h"
 #include "cfghooks.h"
 #include "tree-pass.h"
@@ -40,8 +42,8 @@ Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
 #include "fold-const.h"
 #include "varasm.h"
 #include "stor-layout.h"
-#include "cfganal.h"
 #include "gimplify.h"
+#include "gimple-cfg.h"
 #include "gimple-iterator.h"
 #include "gimplify-me.h"
 #include "tree-cfg.h"
@@ -78,7 +80,6 @@ switch_conversion::collect (gswitch *swtch)
   unsigned int i;
   edge e, e_default, e_first;
   edge_iterator ei;
-  basic_block first;
 
   m_switch = swtch;
 
@@ -87,9 +88,8 @@ switch_conversion::collect (gswitch *swtch)
      Collect the bits we can deduce from the CFG.  */
   m_index_expr = gimple_switch_index (swtch);
   m_switch_bb = gimple_bb (swtch);
-  m_default_bb
-    = label_to_block (CASE_LABEL (gimple_switch_default_label (swtch)));
-  e_default = find_edge (m_switch_bb, m_default_bb);
+  e_default = gimple_switch_default_edge (swtch);
+  m_default_bb = e_default->dest;
   m_default_prob = e_default->probability;
   m_default_count = e_default->count ();
   FOR_EACH_EDGE (e, ei, m_switch_bb->succs)
@@ -120,15 +120,9 @@ switch_conversion::collect (gswitch *swtch)
     }
 
   if (m_contiguous_range)
-    {
-      first = label_to_block (CASE_LABEL (gimple_switch_label (swtch, 1)));
-      e_first = find_edge (m_switch_bb, first);
-    }
+    e_first = gimple_switch_edge (swtch, 1);
   else
-    {
-      first = m_default_bb;
-      e_first = e_default;
-    }
+    e_first = e_default;
 
   /* See if there is one common successor block for all branch
      targets.  If it exists, record it in FINAL_BB.
@@ -1577,15 +1571,11 @@ bit_test_cluster::hoist_edge_and_branch_if_true (gimple_stmt_iterator *gsip,
 void
 switch_decision_tree::compute_cases_per_edge ()
 {
-  basic_block bb = gimple_bb (m_switch);
   reset_out_edges_aux ();
   int ncases = gimple_switch_num_labels (m_switch);
   for (int i = ncases - 1; i >= 1; --i)
     {
-      tree elt = gimple_switch_label (m_switch, i);
-      tree lab = CASE_LABEL (elt);
-      basic_block case_bb = label_to_block_fn (cfun, lab);
-      edge case_edge = find_edge (bb, case_bb);
+      edge case_edge = gimple_switch_edge (m_switch, i);
       case_edge->aux = (void *) ((intptr_t) (case_edge->aux) + 1);
     }
 }
@@ -1602,7 +1592,7 @@ switch_decision_tree::analyze_switch_statement ()
   clusters.create (l - 1);
 
   tree default_label = CASE_LABEL (gimple_switch_default_label (m_switch));
-  basic_block default_bb = label_to_block_fn (cfun, default_label);
+  basic_block default_bb = label_to_block (default_label);
   m_case_bbs.reserve (l);
   m_case_bbs.quick_push (default_bb);
 
@@ -1619,8 +1609,9 @@ switch_decision_tree::analyze_switch_statement ()
 
       profile_probability p
 	= case_edge->probability.apply_scale (1, (intptr_t) (case_edge->aux));
-      clusters.quick_push (new simple_cluster (low, high, elt, case_bb, p));
-      m_case_bbs.quick_push (case_bb);
+      clusters.quick_push (new simple_cluster (low, high, elt, case_edge->dest,
+					       p));
+      m_case_bbs.quick_push (case_edge->dest);
     }
 
   reset_out_edges_aux ();
@@ -1694,9 +1685,8 @@ switch_decision_tree::try_switch_expansion (vec<cluster *> &clusters)
     return false;
 
   /* Find the default case target label.  */
-  tree default_label_expr = CASE_LABEL (gimple_switch_default_label (m_switch));
-  m_default_bb = label_to_block_fn (cfun, default_label_expr);
-  edge default_edge = find_edge (bb, m_default_bb);
+  edge default_edge = gimple_switch_default_edge (m_switch);
+  m_default_bb = default_edge->dest;
 
   /* Do the insertion of a case label into m_case_list.  The labels are
      fed to us in descending order from the sorted vector of case labels used