re PR tree-optimization/68619 (error: loop with header 6 not in loop tree)

2015-12-10  Jeff Law  <law@redhat.com>

	PR tree-optimization/68619
	* tree-ssa-dom.c (dom_opt_dom_walker::before_dom_children): Propgate
	return value from optimize_stmt.
	(dom_opt_dom_walker): Add new argument to dom_walker constructor.
	(pass_dominator:execute): If a block has an unreachable edge,
	remove all jump threads through any successor of the affected block.
	(record_equivalences_from_phis): Ignore alternative if the edge
	does not have EDGE_EXECUTABLE set.
	(single_incoming_edge_ignoring_loop_edges): Similarly.
	(optimize_stmt): If a gimple_code has a compile-time constant
	condition, return the edge taken for that constant value.  Also
	change the condition to true/false as necessary.
	* domwalk.h (dom_walker::dom_walker): Add new argument
	skip_unreachable_blocks.  Don't provide empty constructor body.
	(dom_walker::before_dom_children): Change return type.
	(dom_walker::bb_reachable): Declare new private method.
	(dom_walker::propagate_unreachable_to_edges): Likewise.
	(dom_walker::m_unreachable_dom): Declare new private data member.
	(dom_walker::m_skip_unreachable_blocks): Likewise.
	* domwalk.c: Include dumpfile.h.
	(dom_walker::dom_walker): New constructor.  Initialize private data
	members.  If needed, set EDGE_EXECUTABLE for all edges in the CFG,
	extracted from tree-ssa-sccvn.c.
	(dom_walker::bb_reachable): New method extracted from tree-ssa-sccvn.c
	(dom_walker::propagate_unreachable_to_edges): Likewise.
	(dom_walker::walk): Only call before_dom_children on reachable
	blocks.  If before_dom_children returns an edge, then clear
	EDGE_EXECUTABLE for all other outgoing edges from the same block.
	For unreachable blocks, call propagate_unreachable_to_edges.
	Similarly, only call after_dom_children on reachable blocks.  For
	unreachable blocks, conditionally clear m_unreachable_dom.
	* tree-ssa-sccvn.c (sccvn_dom_walker::unreachable_dom): Remove
	private data member.
	(sccvn_dom_walker::after_dom_children): Use methods from dom_walker
	class.
	(run_scc_vn): Likewise.
	(sccvn_dom_walker::before_dom_children): Likewise.  Return the taken
	outgoing edge if a COND, SWITCH, or GOTO are optimized.
	* compare-elim.c (find_comparison_dom_walker::before_dom_children):
	Change return type to an edge.  Always return NULL.
	* fwprop.c (single_def_use_dom_walker::before_dom_children): Likewise.
	* gimple-ssa-strength-reduction.c
	(find_candidates_dom_walker::before_dom_children): Likewise.
	* ipa-prop.c (analysis_dom_walker::before_dom_children): Likewise.
	(ipcp_modif_dom_walker::before_dom_children): Likewise.
	* tree-into-ssa.c (rewrite_dom_walker::before_dom_children): Likewise.
	(rewrite_update_dom_walker::before_dom_children): Likewise.
	(mark_def_dom_children::before_dom_children): Likewise.
	* tree-ssa-dse.c (dse_dom_walker::before_dom_children): Likewise.
	* tree-ssa-loop-im.c
	(invariantness_dom_walker::before_dom_children): Likewise.
	(move_computations_dom_walker::before_dom_walker): Likewise.
	* tree-ssa-phiopt.c
	(nontrapping_dom_walker::before_dom_children): Likewise.
	* tree-ssa-pre.c
	(eliminate_dom_walker::before_dom_children): Likewise.
	* tree-ssa-propagate.c
	(substitute_and_fold_dom_walker::before_dom_children): Likewise.
	* tree-ssa-strlen.c
	(strlen_dom_walker::before_dom_children): Likewise.
	* tree-ssa-uncprop.c
	(uncprop_dom_walker::before_dom_children): Likewise.

	PR tree-optimization/68619
	* gcc.dg/tree-ssa/pr68619-1.c: New test.
	* gcc.dg/tree-ssa/pr68619-2.c: New test.
	* gcc.dg/tree-ssa/pr68619-3.c: New test.
	* gcc.dg/tree-ssa/pr68619-4.c: New test.
	* gcc.dg/tree-ssa/pr68619-5.c: New test.

From-SVN: r231527

1 files changed, 12 insertions, 7 deletions

diff --git a/gcc/tree-into-ssa.c b/gcc/tree-into-ssa.c
index 3086f82..5486d5c 100644
--- a/gcc/tree-into-ssa.c
+++ b/gcc/tree-into-ssa.c
@@ -1391,7 +1391,7 @@ class rewrite_dom_walker : public dom_walker
 public:
   rewrite_dom_walker (cdi_direction direction) : dom_walker (direction) {}
 
-  virtual void before_dom_children (basic_block);
+  virtual edge before_dom_children (basic_block);
   virtual void after_dom_children (basic_block);
 };
 
@@ -1400,7 +1400,7 @@ public:
    (BLOCK_DEFS).  Register new definitions for every PHI node in the
    block.  */
 
-void
+edge
 rewrite_dom_walker::before_dom_children (basic_block bb)
 {
   if (dump_file && (dump_flags & TDF_DETAILS))
@@ -1432,6 +1432,8 @@ rewrite_dom_walker::before_dom_children (basic_block bb)
      reaching definition for the variable and the edge through which that
      definition is reaching the PHI node.  */
   rewrite_add_phi_arguments (bb);
+
+  return NULL;
 }
 
 
@@ -2055,7 +2057,7 @@ class rewrite_update_dom_walker : public dom_walker
 public:
   rewrite_update_dom_walker (cdi_direction direction) : dom_walker (direction) {}
 
-  virtual void before_dom_children (basic_block);
+  virtual edge before_dom_children (basic_block);
   virtual void after_dom_children (basic_block);
 };
 
@@ -2064,7 +2066,7 @@ public:
    for new SSA names produced in this block (BLOCK_DEFS).  Register
    new definitions for every PHI node in the block.  */
 
-void
+edge
 rewrite_update_dom_walker::before_dom_children (basic_block bb)
 {
   bool is_abnormal_phi;
@@ -2077,7 +2079,7 @@ rewrite_update_dom_walker::before_dom_children (basic_block bb)
   block_defs_stack.safe_push (NULL_TREE);
 
   if (!bitmap_bit_p (blocks_to_update, bb->index))
-    return;
+    return NULL;
 
   /* Mark the LHS if any of the arguments flows through an abnormal
      edge.  */
@@ -2133,6 +2135,8 @@ rewrite_update_dom_walker::before_dom_children (basic_block bb)
 
   /* Step 3.  Update PHI nodes.  */
   rewrite_update_phi_arguments (bb);
+
+  return NULL;
 }
 
 /* Called after visiting block BB.  Unwind BLOCK_DEFS_STACK to restore
@@ -2210,7 +2214,7 @@ public:
   mark_def_dom_walker (cdi_direction direction);
   ~mark_def_dom_walker ();
 
-  virtual void before_dom_children (basic_block);
+  virtual edge before_dom_children (basic_block);
 
 private:
   /* Notice that this bitmap is indexed using variable UIDs, so it must be
@@ -2232,7 +2236,7 @@ mark_def_dom_walker::~mark_def_dom_walker ()
 /* Block processing routine for mark_def_sites.  Clear the KILLS bitmap
    at the start of each block, and call mark_def_sites for each statement.  */
 
-void
+edge
 mark_def_dom_walker::before_dom_children (basic_block bb)
 {
   gimple_stmt_iterator gsi;
@@ -2240,6 +2244,7 @@ mark_def_dom_walker::before_dom_children (basic_block bb)
   bitmap_clear (m_kills);
   for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
     mark_def_sites (bb, gsi_stmt (gsi), m_kills);
+  return NULL;
 }
 
 /* Initialize internal data needed during renaming.  */