re PR tree-optimization/66856 (ICE in compute_live_loop_exits, at tree-ssa-loop-manip.c:234)

2016-01-15  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/66856
	* tree-vect-loop.c (vect_transform_loop): Free SLP instances here.
	* tree-vect-slp.c (vect_free_slp_tree): Decrement stmt reference count.
	(vect_create_new_slp_node): Increment stmt reference count.
	(vect_get_and_check_slp_defs): Make sure stmts are nor already in
	an SLP tree before swapping operands.
	(vect_build_slp_tree): Likewise.
	(destroy_bb_vec_info): Free stmt info after SLP instances.
	* tree-vect-stmts.c (new_stmt_vec_info): Initialize reference count.
	* tree-vectorizer.h (struct _stmt_vec_info): Add num_slp_uses field.
	(STMT_VINFO_NUM_SLP_USES): New macro.

	* gcc.dg/torture/pr66856-1.c: New testcase.
	* gcc.dg/torture/pr66856-2.c: Likewise.

From-SVN: r232435

gcc/ChangeLog

 2016-01-15  Richard Biener  <rguenther@suse.de>
 
+	PR tree-optimization/66856
+	* tree-vect-loop.c (vect_transform_loop): Free SLP instances here.
+	* tree-vect-slp.c (vect_free_slp_tree): Decrement stmt reference count.
+	(vect_create_new_slp_node): Increment stmt reference count.
+	(vect_get_and_check_slp_defs): Make sure stmts are nor already in
+	an SLP tree before swapping operands.
+	(vect_build_slp_tree): Likewise.
+	(destroy_bb_vec_info): Free stmt info after SLP instances.
+	* tree-vect-stmts.c (new_stmt_vec_info): Initialize reference count.
+	* tree-vectorizer.h (struct _stmt_vec_info): Add num_slp_uses field.
+	(STMT_VINFO_NUM_SLP_USES): New macro.
+
+2016-01-15  Richard Biener  <rguenther@suse.de>
+
 	PR debug/69137
 	* dwarf2out.c (add_linkage_name_raw): New function split out from ...
 	(add_linkage_name): ... here.

gcc/testsuite/ChangeLog

 2016-01-15  Richard Biener  <rguenther@suse.de>
 
+	PR tree-optimization/66856
+	* gcc.dg/torture/pr66856-1.c: New testcase.
+	* gcc.dg/torture/pr66856-2.c: Likewise.
+
+2016-01-15  Richard Biener  <rguenther@suse.de>
+
 	PR debug/69137
 	* g++.dg/lto/pr69137_0.C: New testcase.
 

gcc/testsuite/gcc.dg/torture/pr66856-1.c

+/* { dg-do compile } */
+/* { dg-additional-options "-mavx2" { target x86_64-*-* i?86-*-* } } */
+
+short c;
+int d;
+int fn1(int p1, int p2) {
+    int a, b;
+    a = p1 >> 3 & p2;
+    b = p1 & 072;
+    a |= a >> 5;
+    a |= b >> 5;
+    return a;
+}
+void fn2() {
+    short *e = &c;
+    int *f;
+    int g;
+    while (d -= 4) {
+	fn1(1, 1);
+	fn1(1, 1) * fn1(1, 1) * fn1(1, 1);
+	*e++ = fn1(*f++, g);
+	*e++ = fn1(*f++, g);
+    }
+}

gcc/testsuite/gcc.dg/torture/pr66856-2.c

+/* { dg-do compile } */
+
+typedef int uint32_t;
+int c, e, f, g, h;
+short *d;
+uint32_t fn1(uint32_t p1, uint32_t p2)
+{
+  uint32_t a, b;
+  a = p1 >> 3 & p2;
+  b = p1 & 072;
+  a |= a >> 5;
+  a |= b >> 5;
+  return a;
+}
+
+void fn2()
+{
+  uint32_t *i;
+  uint32_t j;
+  while (c -= 4) {
+      fn1(e, j);
+      fn1(f, j) * fn1(g, j) * fn1(h, j);
+      *d++ = fn1(*i++, j);
+      *d++ = fn1(*i++, j);
+  }
+}

gcc/tree-vect-loop.c

@@ -6930,4 +6930,11 @@ vect_transform_loop (loop_vec_info loop_vinfo)
 			 "OUTER LOOP VECTORIZED\n");
       dump_printf (MSG_NOTE, "\n");
     }
+
+  /* Free SLP instances here because otherwise stmt reference counting
+     won't work.  */
+  slp_instance instance;
+  FOR_EACH_VEC_ELT (LOOP_VINFO_SLP_INSTANCES (loop_vinfo), i, instance)
+    vect_free_slp_instance (instance);
+  LOOP_VINFO_SLP_INSTANCES (loop_vinfo).release ();
 }

gcc/tree-vect-slp.c

@@ -54,6 +54,15 @@ vect_free_slp_tree (slp_tree node)
   FOR_EACH_VEC_ELT (SLP_TREE_CHILDREN (node), i, child)
     vect_free_slp_tree (child);
 
+  gimple *stmt;
+  FOR_EACH_VEC_ELT (SLP_TREE_SCALAR_STMTS (node), i, stmt)
+    /* After transform some stmts are removed and thus their vinfo is gone.  */
+    if (vinfo_for_stmt (stmt))
+      {
+	gcc_assert (STMT_VINFO_NUM_SLP_USES (vinfo_for_stmt (stmt)) > 0);
+	STMT_VINFO_NUM_SLP_USES (vinfo_for_stmt (stmt))--;
+      }
+
   SLP_TREE_CHILDREN (node).release ();
   SLP_TREE_SCALAR_STMTS (node).release ();
   SLP_TREE_VEC_STMTS (node).release ();
@@ -102,6 +111,10 @@ vect_create_new_slp_node (vec<gimple *> scalar_stmts)
   SLP_TREE_TWO_OPERATORS (node) = false;
   SLP_TREE_DEF_TYPE (node) = vect_internal_def;
 
+  unsigned i;
+  FOR_EACH_VEC_ELT (scalar_stmts, i, stmt)
+    STMT_VINFO_NUM_SLP_USES (vinfo_for_stmt (stmt))++;
+
   return node;
 }
 
@@ -401,6 +414,20 @@ again:
   /* Swap operands.  */
   if (swapped)
     {
+      /* If there are already uses of this stmt in a SLP instance then
+         we've committed to the operand order and can't swap it.  */
+      if (STMT_VINFO_NUM_SLP_USES (vinfo_for_stmt (stmt)) != 0)
+	{
+	  if (dump_enabled_p ())
+	    {
+	      dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
+			       "Build SLP failed: cannot swap operands of "
+			       "shared stmt ");
+	      dump_gimple_stmt (MSG_MISSED_OPTIMIZATION, TDF_SLIM, stmt, 0);
+	    }
+	  return -1;
+	}
+
       if (first_op_cond)
 	{
 	  tree cond = gimple_assign_rhs1 (stmt);
@@ -411,6 +438,12 @@ again:
       else
 	swap_ssa_operands (stmt, gimple_assign_rhs1_ptr (stmt),
 			   gimple_assign_rhs2_ptr (stmt));
+      if (dump_enabled_p ())
+	{
+	  dump_printf_loc (MSG_NOTE, vect_location,
+			   "swapped operands to match def types in ");
+	  dump_gimple_stmt (MSG_NOTE, TDF_SLIM, stmt, 0);
+	}
     }
 
   return 0;
@@ -1007,6 +1040,23 @@ vect_build_slp_tree (vec_info *vinfo,
 	     behavior.  */
 	  && *npermutes < 4)
 	{
+	  /* Verify if we can safely swap or if we committed to a specific
+	     operand order already.  */
+	  for (j = 0; j < group_size; ++j)
+	    if (!matches[j]
+		&& STMT_VINFO_NUM_SLP_USES (vinfo_for_stmt (stmts[j])) != 0)
+	      {
+		if (dump_enabled_p ())
+		  {
+		    dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
+				     "Build SLP failed: cannot swap operands "
+				     "of shared stmt ");
+		    dump_gimple_stmt (MSG_MISSED_OPTIMIZATION, TDF_SLIM,
+				      stmts[j], 0);
+		  }
+		goto fail;
+	      }
+
 	  /* Swap mismatched definition stmts.  */
 	  dump_printf_loc (MSG_NOTE, vect_location,
 			   "Re-trying with swapped operands of stmts ");
@@ -1095,6 +1145,7 @@ vect_build_slp_tree (vec_info *vinfo,
 	  ++*npermutes;
 	}
 
+fail:
       gcc_assert (child == NULL);
       FOR_EACH_VEC_ELT (children, j, child)
 	vect_free_slp_tree (child);
@@ -2186,18 +2237,21 @@ new_bb_vec_info (gimple_stmt_iterator region_begin,
 static void
 destroy_bb_vec_info (bb_vec_info bb_vinfo)
 {
-  vec<slp_instance> slp_instances;
   slp_instance instance;
-  basic_block bb;
-  gimple_stmt_iterator si;
   unsigned i;
 
   if (!bb_vinfo)
     return;
 
-  bb = BB_VINFO_BB (bb_vinfo);
+  vect_destroy_datarefs (bb_vinfo);
+  free_dependence_relations (BB_VINFO_DDRS (bb_vinfo));
+  BB_VINFO_GROUPED_STORES (bb_vinfo).release ();
+  FOR_EACH_VEC_ELT (BB_VINFO_SLP_INSTANCES (bb_vinfo), i, instance)
+    vect_free_slp_instance (instance);
+  BB_VINFO_SLP_INSTANCES (bb_vinfo).release ();
+  destroy_cost_data (BB_VINFO_TARGET_COST_DATA (bb_vinfo));
 
-  for (si = bb_vinfo->region_begin;
+  for (gimple_stmt_iterator si = bb_vinfo->region_begin;
        gsi_stmt (si) != gsi_stmt (bb_vinfo->region_end); gsi_next (&si))
     {
       gimple *stmt = gsi_stmt (si);
@@ -2211,16 +2265,8 @@ destroy_bb_vec_info (bb_vec_info bb_vinfo)
       gimple_set_uid (stmt, -1);
     }
 
-  vect_destroy_datarefs (bb_vinfo);
-  free_dependence_relations (BB_VINFO_DDRS (bb_vinfo));
-  BB_VINFO_GROUPED_STORES (bb_vinfo).release ();
-  slp_instances = BB_VINFO_SLP_INSTANCES (bb_vinfo);
-  FOR_EACH_VEC_ELT (slp_instances, i, instance)
-    vect_free_slp_instance (instance);
-  BB_VINFO_SLP_INSTANCES (bb_vinfo).release ();
-  destroy_cost_data (BB_VINFO_TARGET_COST_DATA (bb_vinfo));
+  BB_VINFO_BB (bb_vinfo)->aux = NULL;
   free (bb_vinfo);
-  bb->aux = NULL;
 }
 
 

gcc/tree-vect-stmts.c

@@ -8391,6 +8391,8 @@ new_stmt_vec_info (gimple *stmt, vec_info *vinfo)
 
   STMT_VINFO_SAME_ALIGN_REFS (res).create (0);
   STMT_SLP_TYPE (res) = loop_vect;
+  STMT_VINFO_NUM_SLP_USES (res) = 0;
+
   GROUP_FIRST_ELEMENT (res) = NULL;
   GROUP_NEXT_ELEMENT (res) = NULL;
   GROUP_SIZE (res) = 0;

gcc/tree-vectorizer.h

@@ -601,6 +601,8 @@ typedef struct _stmt_vec_info {
   /* For reduction loops, this is the type of reduction.  */
   enum vect_reduction_type v_reduc_type;
 
+  /* The number of scalar stmt references from active SLP instances.  */
+  unsigned int num_slp_uses;
 } *stmt_vec_info;
 
 /* Access Functions.  */
@@ -653,6 +655,7 @@ STMT_VINFO_BB_VINFO (stmt_vec_info stmt_vinfo)
 #define STMT_VINFO_LOOP_PHI_EVOLUTION_BASE_UNCHANGED(S) (S)->loop_phi_evolution_base_unchanged
 #define STMT_VINFO_LOOP_PHI_EVOLUTION_PART(S) (S)->loop_phi_evolution_part
 #define STMT_VINFO_MIN_NEG_DIST(S)	(S)->min_neg_dist
+#define STMT_VINFO_NUM_SLP_USES(S)	(S)->num_slp_uses
 
 #define GROUP_FIRST_ELEMENT(S)          (S)->first_element
 #define GROUP_NEXT_ELEMENT(S)           (S)->next_element