re PR tree-optimization/84427 (gcc ICE at -O3 on x86_64-linux-gnu in…

re PR tree-optimization/84427 (gcc ICE at -O3 on x86_64-linux-gnu in compute_antic, at tree-ssa-pre.c:2356)

2018-03-02  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/84427
	* tree-ssa-pre.c (bitmap_remove_expr_from_set): Remove.
	(bitmap_set_subtract_values): Rewrite to handle multiple
	exprs per value.
	(clean): Likewise.
	(prune_clobbered_mems): Likewise.
	(phi_translate): Take edge instead of pred/phiblock.
	(phi_translate_1): Likewise.
	(phi_translate_set): Likewise.  Insert all translated
	exprs for a value into the set, keeping possibly multiple
	expressions per value.
	(compute_antic_aux): Adjust for phi_translate changes.
	When intersecting union the expressions and prune those
	not in the final value set, keeping possibly multiple
	expressions per value.  Do not use value-insertion
	for unioning ANTIC_OUT U EXP_GEN - TMP_GEN but merge
	all expressions.  Add verification that the value-sets
	only shrink during iteration.
	(compute_partial_antic_aux): Adjust for the phi_translate changes.
	(do_pre_regular_insertion): Likewise.
	(do_pre_partial_partial_insertion): Likewise.

	* gcc.dg/torture/pr84427.c: New testcase.

From-SVN: r258124

gcc/ChangeLog

 2018-03-02  Richard Biener  <rguenther@suse.de>
 
+	PR tree-optimization/84427
+	* tree-ssa-pre.c (bitmap_remove_expr_from_set): Remove.
+	(bitmap_set_subtract_values): Rewrite to handle multiple
+	exprs per value.
+	(clean): Likewise.
+	(prune_clobbered_mems): Likewise.
+	(phi_translate): Take edge instead of pred/phiblock.
+	(phi_translate_1): Likewise.
+	(phi_translate_set): Likewise.  Insert all translated
+	exprs for a value into the set, keeping possibly multiple
+	expressions per value.
+	(compute_antic_aux): Adjust for phi_translate changes.
+	When intersecting union the expressions and prune those
+	not in the final value set, keeping possibly multiple
+	expressions per value.  Do not use value-insertion
+	for unioning ANTIC_OUT U EXP_GEN - TMP_GEN but merge
+	all expressions.  Add verification that the value-sets
+	only shrink during iteration.
+	(compute_partial_antic_aux): Adjust for the phi_translate changes.
+	(do_pre_regular_insertion): Likewise.
+	(do_pre_partial_partial_insertion): Likewise.
+
+2018-03-02  Richard Biener  <rguenther@suse.de>
+
 	PR target/82005
 	* config/darwin.c (saved_debug_info_level): New static global.
 	(darwin_asm_lto_start): Disable debug info generation for LTO out.

gcc/testsuite/ChangeLog

+2018-03-02  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/84427
+	* gcc.dg/torture/pr84427.c: New testcase.
+
 2018-03-01  Peter Bergner  <bergner@vnet.ibm.com>
 
 	PR target/84534

gcc/testsuite/gcc.dg/torture/pr84427.c

+/* { dg-do compile } */
+
+short a, d, e;
+unsigned char b;
+int c, f;
+char g, h;
+void fn2(int, int);
+void fn1() { fn2(e, a); }
+void fn2(int p1, int p2)
+{
+l1:
+  b = a;
+  for (; h; h--)
+    if (p1)
+      g = p2 * c;
+    else
+      {
+	c = d;
+	if (f)
+	  goto l1;
+      }
+}

gcc/tree-ssa-pre.c

@@ -696,16 +696,6 @@ sccvn_valnum_from_value_id (unsigned int val)
   return NULL_TREE;
 }
 
-/* Remove an expression EXPR from a bitmapped set.  */
-
-static void
-bitmap_remove_expr_from_set (bitmap_set_t set, pre_expr expr)
-{
-  unsigned int val  = get_expr_value_id (expr);
-  bitmap_clear_bit (&set->values, val);
-  bitmap_clear_bit (&set->expressions, get_expression_id (expr));
-}
-
 /* Insert an expression EXPR into a bitmapped set.  */
 
 static void
@@ -805,20 +795,21 @@ bitmap_set_subtract_values (bitmap_set_t a, bitmap_set_t b)
 {
   unsigned int i;
   bitmap_iterator bi;
-  pre_expr to_remove = NULL;
+  unsigned to_remove = -1U;
+  bitmap_and_compl_into (&a->values, &b->values);
   FOR_EACH_EXPR_ID_IN_SET (a, i, bi)
     {
-      if (to_remove)
+      if (to_remove != -1U)
 	{
-	  bitmap_remove_expr_from_set (a, to_remove);
-	  to_remove = NULL;
+	  bitmap_clear_bit (&a->expressions, to_remove);
+	  to_remove = -1U;
 	}
       pre_expr expr = expression_for_id (i);
-      if (bitmap_bit_p (&b->values, get_expr_value_id (expr)))
-	to_remove = expr;
+      if (! bitmap_bit_p (&a->values, get_expr_value_id (expr)))
+	to_remove = i;
     }
-  if (to_remove)
-    bitmap_remove_expr_from_set (a, to_remove);
+  if (to_remove != -1U)
+    bitmap_clear_bit (&a->expressions, to_remove);
 }
 
 
@@ -1335,17 +1326,17 @@ get_representative_for (const pre_expr e, basic_block b = NULL)
 
 
 static pre_expr
-phi_translate (pre_expr expr, bitmap_set_t set1, bitmap_set_t set2,
-	       basic_block pred, basic_block phiblock);
+phi_translate (pre_expr expr, bitmap_set_t set1, bitmap_set_t set2, edge e);
 
 /* Translate EXPR using phis in PHIBLOCK, so that it has the values of
    the phis in PRED.  Return NULL if we can't find a leader for each part
    of the translated expression.  */
 
 static pre_expr
-phi_translate_1 (pre_expr expr, bitmap_set_t set1, bitmap_set_t set2,
-		 basic_block pred, basic_block phiblock)
+phi_translate_1 (pre_expr expr, bitmap_set_t set1, bitmap_set_t set2, edge e)
 {
+  basic_block pred = e->src;
+  basic_block phiblock = e->dest;
   switch (expr->kind)
     {
     case NARY:
@@ -1366,7 +1357,7 @@ phi_translate_1 (pre_expr expr, bitmap_set_t set1, bitmap_set_t set2,
                 pre_expr leader, result;
 		unsigned int op_val_id = VN_INFO (newnary->op[i])->value_id;
 		leader = find_leader_in_sets (op_val_id, set1, set2);
-                result = phi_translate (leader, set1, set2, pred, phiblock);
+		result = phi_translate (leader, set1, set2, e);
 		if (result && result != leader)
 		  /* Force a leader as well as we are simplifying this
 		     expression.  */
@@ -1397,7 +1388,7 @@ phi_translate_1 (pre_expr expr, bitmap_set_t set1, bitmap_set_t set2,
 		       to be inserted and increased register pressure.
 		       See PR77498 - this avoids doing predcoms work in
 		       a less efficient way.  */
-		    if (find_edge (pred, phiblock)->flags & EDGE_DFS_BACK)
+		    if (e->flags & EDGE_DFS_BACK)
 		      ;
 		    else
 		      {
@@ -1488,7 +1479,7 @@ phi_translate_1 (pre_expr expr, bitmap_set_t set1, bitmap_set_t set2,
 		  }
 		op_val_id = VN_INFO (op[n])->value_id;
 		leader = find_leader_in_sets (op_val_id, set1, set2);
-		opresult = phi_translate (leader, set1, set2, pred, phiblock);
+		opresult = phi_translate (leader, set1, set2, e);
 		if (opresult && opresult != leader)
 		  {
 		    tree name = get_representative_for (opresult);
@@ -1616,7 +1607,6 @@ phi_translate_1 (pre_expr expr, bitmap_set_t set1, bitmap_set_t set2,
 	if (gimple_code (def_stmt) == GIMPLE_PHI
 	    && gimple_bb (def_stmt) == phiblock)
 	  {
-	    edge e = find_edge (pred, gimple_bb (def_stmt));
 	    tree def = PHI_ARG_DEF (def_stmt, e->dest_idx);
 
 	    /* Handle constant. */
@@ -1639,8 +1629,7 @@ phi_translate_1 (pre_expr expr, bitmap_set_t set1, bitmap_set_t set2,
 /* Wrapper around phi_translate_1 providing caching functionality.  */
 
 static pre_expr
-phi_translate (pre_expr expr, bitmap_set_t set1, bitmap_set_t set2,
-	       basic_block pred, basic_block phiblock)
+phi_translate (pre_expr expr, bitmap_set_t set1, bitmap_set_t set2, edge e)
 {
   expr_pred_trans_t slot = NULL;
   pre_expr phitrans;
@@ -1658,7 +1647,7 @@ phi_translate (pre_expr expr, bitmap_set_t set1, bitmap_set_t set2,
   /* Don't add translations of NAMEs as those are cheap to translate.  */
   if (expr->kind != NAME)
     {
-      if (phi_trans_add (&slot, expr, pred))
+      if (phi_trans_add (&slot, expr, e->src))
 	return slot->v;
       /* Store NULL for the value we want to return in the case of
 	 recursing.  */
@@ -1666,7 +1655,7 @@ phi_translate (pre_expr expr, bitmap_set_t set1, bitmap_set_t set2,
     }
 
   /* Translate.  */
-  phitrans = phi_translate_1 (expr, set1, set2, pred, phiblock);
+  phitrans = phi_translate_1 (expr, set1, set2, e);
 
   if (slot)
     {
@@ -1687,14 +1676,13 @@ phi_translate (pre_expr expr, bitmap_set_t set1, bitmap_set_t set2,
    expressions in DEST.  */
 
 static void
-phi_translate_set (bitmap_set_t dest, bitmap_set_t set, basic_block pred,
-		   basic_block phiblock)
+phi_translate_set (bitmap_set_t dest, bitmap_set_t set, edge e)
 {
   vec<pre_expr> exprs;
   pre_expr expr;
   int i;
 
-  if (gimple_seq_empty_p (phi_nodes (phiblock)))
+  if (gimple_seq_empty_p (phi_nodes (e->dest)))
     {
       bitmap_set_copy (dest, set);
       return;
@@ -1704,18 +1692,11 @@ phi_translate_set (bitmap_set_t dest, bitmap_set_t set, basic_block pred,
   FOR_EACH_VEC_ELT (exprs, i, expr)
     {
       pre_expr translated;
-      translated = phi_translate (expr, set, NULL, pred, phiblock);
+      translated = phi_translate (expr, set, NULL, e);
       if (!translated)
 	continue;
 
-      /* We might end up with multiple expressions from SET being
-	 translated to the same value.  In this case we do not want
-	 to retain the NARY or REFERENCE expression but prefer a NAME
-	 which would be the leader.  */
-      if (translated->kind == NAME)
-	bitmap_value_replace_in_set (dest, translated);
-      else
-	bitmap_value_insert_into_set (dest, translated);
+      bitmap_insert_into_set (dest, translated);
     }
   exprs.release ();
 }
@@ -1918,7 +1899,15 @@ clean (bitmap_set_t set1, bitmap_set_t set2 = NULL)
   FOR_EACH_VEC_ELT (exprs, i, expr)
     {
       if (!valid_in_sets (set1, set2, expr))
-	bitmap_remove_expr_from_set (set1, expr);
+	{
+	  unsigned int val  = get_expr_value_id (expr);
+	  bitmap_clear_bit (&set1->expressions, get_expression_id (expr));
+	  /* We are entered with possibly multiple expressions for a value
+	     so before removing a value from the set see if there's an
+	     expression for it left.  */
+	  if (! bitmap_find_leader (set1, val))
+	    bitmap_clear_bit (&set1->values, val);
+	}
     }
   exprs.release ();
 }
@@ -1931,15 +1920,17 @@ prune_clobbered_mems (bitmap_set_t set, basic_block block)
 {
   bitmap_iterator bi;
   unsigned i;
-  pre_expr to_remove = NULL;
+  unsigned to_remove = -1U;
+  bool any_removed = false;
 
   FOR_EACH_EXPR_ID_IN_SET (set, i, bi)
     {
       /* Remove queued expr.  */
-      if (to_remove)
+      if (to_remove != -1U)
 	{
-	  bitmap_remove_expr_from_set (set, to_remove);
-	  to_remove = NULL;
+	  bitmap_clear_bit (&set->expressions, to_remove);
+	  any_removed = true;
+	  to_remove = -1U;
 	}
 
       pre_expr expr = expression_for_id (i);
@@ -1955,7 +1946,7 @@ prune_clobbered_mems (bitmap_set_t set, basic_block block)
 					   block, gimple_bb (def_stmt)))
 		      || (gimple_bb (def_stmt) == block
 			  && value_dies_in_block_x (expr, block))))
-		to_remove = expr;
+		to_remove = i;
 	    }
 	}
       else if (expr->kind == NARY)
@@ -1967,13 +1958,36 @@ prune_clobbered_mems (bitmap_set_t set, basic_block block)
 	     as the available expression might be after the exit point.  */
 	  if (BB_MAY_NOTRETURN (block)
 	      && vn_nary_may_trap (nary))
-	    to_remove = expr;
+	    to_remove = i;
 	}
     }
 
   /* Remove queued expr.  */
-  if (to_remove)
-    bitmap_remove_expr_from_set (set, to_remove);
+  if (to_remove != -1U)
+    {
+      bitmap_clear_bit (&set->expressions, to_remove);
+      any_removed = true;
+    }
+
+  /* Above we only removed expressions, now clean the set of values
+     which no longer have any corresponding expression.  We cannot
+     clear the value at the time we remove an expression since there
+     may be multiple expressions per value.
+     If we'd queue possibly to be removed values we could use
+     the bitmap_find_leader way to see if there's still an expression
+     for it.  For some ratio of to be removed values and number of
+     values/expressions in the set this might be faster than rebuilding
+     the value-set.  */
+  if (any_removed)
+    {
+      bitmap_clear (&set->values);
+      FOR_EACH_EXPR_ID_IN_SET (set, i, bi)
+	{
+	  pre_expr expr = expression_for_id (i);
+	  unsigned int value_id = get_expr_value_id (expr);
+	  bitmap_set_bit (&set->values, value_id);
+	}
+    }
 }
 
 static sbitmap has_abnormal_preds;
@@ -1993,11 +2007,10 @@ static bool
 compute_antic_aux (basic_block block, bool block_has_abnormal_pred_edge)
 {
   bitmap_set_t S, old, ANTIC_OUT;
-  bitmap_iterator bi;
-  unsigned int bii;
   edge e;
   edge_iterator ei;
 
+  bool was_visited = BB_VISITED (block);
   bool changed = ! BB_VISITED (block);
   BB_VISITED (block) = 1;
   old = ANTIC_OUT = S = NULL;
@@ -2017,9 +2030,9 @@ compute_antic_aux (basic_block block, bool block_has_abnormal_pred_edge)
      translate through.  */
   else if (single_succ_p (block))
     {
-      basic_block succ_bb = single_succ (block);
-      gcc_assert (BB_VISITED (succ_bb));
-      phi_translate_set (ANTIC_OUT, ANTIC_IN (succ_bb), block, succ_bb);
+      e = single_succ_edge (block);
+      gcc_assert (BB_VISITED (e->dest));
+      phi_translate_set (ANTIC_OUT, ANTIC_IN (e->dest), e);
     }
   /* If we have multiple successors, we take the intersection of all of
      them.  Note that in the case of loop exit phi nodes, we may have
@@ -2027,16 +2040,16 @@ compute_antic_aux (basic_block block, bool block_has_abnormal_pred_edge)
   else
     {
       size_t i;
-      basic_block bprime, first = NULL;
+      edge first = NULL;
 
-      auto_vec<basic_block> worklist (EDGE_COUNT (block->succs));
+      auto_vec<edge> worklist (EDGE_COUNT (block->succs));
       FOR_EACH_EDGE (e, ei, block->succs)
 	{
 	  if (!first
 	      && BB_VISITED (e->dest))
-	    first = e->dest;
+	    first = e;
 	  else if (BB_VISITED (e->dest))
-	    worklist.quick_push (e->dest);
+	    worklist.quick_push (e);
 	  else
 	    {
 	      /* Unvisited successors get their ANTIC_IN replaced by the
@@ -2053,7 +2066,7 @@ compute_antic_aux (basic_block block, bool block_has_abnormal_pred_edge)
          which is guaranteed by iteration order.  */
       gcc_assert (first != NULL);
 
-      phi_translate_set (ANTIC_OUT, ANTIC_IN (first), block, first);
+      phi_translate_set (ANTIC_OUT, ANTIC_IN (first->dest), first);
 
       /* If we have multiple successors we need to intersect the ANTIC_OUT
          sets.  For values that's a simple intersection but for
@@ -2062,31 +2075,29 @@ compute_antic_aux (basic_block block, bool block_has_abnormal_pred_edge)
 	 Avoid randomness and running into cycles like for PR82129 and
 	 canonicalize the expression we choose to the one with the
 	 lowest id.  This requires we actually compute the union first.  */
-      FOR_EACH_VEC_ELT (worklist, i, bprime)
+      FOR_EACH_VEC_ELT (worklist, i, e)
 	{
-	  if (!gimple_seq_empty_p (phi_nodes (bprime)))
+	  if (!gimple_seq_empty_p (phi_nodes (e->dest)))
 	    {
 	      bitmap_set_t tmp = bitmap_set_new ();
-	      phi_translate_set (tmp, ANTIC_IN (bprime), block, bprime);
+	      phi_translate_set (tmp, ANTIC_IN (e->dest), e);
 	      bitmap_and_into (&ANTIC_OUT->values, &tmp->values);
 	      bitmap_ior_into (&ANTIC_OUT->expressions, &tmp->expressions);
 	      bitmap_set_free (tmp);
 	    }
 	  else
 	    {
-	      bitmap_and_into (&ANTIC_OUT->values, &ANTIC_IN (bprime)->values);
+	      bitmap_and_into (&ANTIC_OUT->values, &ANTIC_IN (e->dest)->values);
 	      bitmap_ior_into (&ANTIC_OUT->expressions,
-			       &ANTIC_IN (bprime)->expressions);
+			       &ANTIC_IN (e->dest)->expressions);
 	    }
 	}
       if (! worklist.is_empty ())
 	{
-	  /* Prune expressions not in the value set, canonicalizing to
-	     expression with lowest ID.  */
+	  /* Prune expressions not in the value set.  */
 	  bitmap_iterator bi;
 	  unsigned int i;
 	  unsigned int to_clear = -1U;
-	  bitmap seen_value = BITMAP_ALLOC (NULL);
 	  FOR_EACH_EXPR_ID_IN_SET (ANTIC_OUT, i, bi)
 	    {
 	      if (to_clear != -1U)
@@ -2096,13 +2107,11 @@ compute_antic_aux (basic_block block, bool block_has_abnormal_pred_edge)
 		}
 	      pre_expr expr = expression_for_id (i);
 	      unsigned int value_id = get_expr_value_id (expr);
-	      if (!bitmap_bit_p (&ANTIC_OUT->values, value_id)
-		  || !bitmap_set_bit (seen_value, value_id))
+	      if (!bitmap_bit_p (&ANTIC_OUT->values, value_id))
 		to_clear = i;
 	    }
 	  if (to_clear != -1U)
 	    bitmap_clear_bit (&ANTIC_OUT->expressions, to_clear);
-	  BITMAP_FREE (seen_value);
 	}
     }
 
@@ -2119,15 +2128,26 @@ compute_antic_aux (basic_block block, bool block_has_abnormal_pred_edge)
 
   /* Then union in the ANTIC_OUT - TMP_GEN values,
      to get ANTIC_OUT U EXP_GEN - TMP_GEN */
-  FOR_EACH_EXPR_ID_IN_SET (S, bii, bi)
-    bitmap_value_insert_into_set (ANTIC_IN (block),
-				  expression_for_id (bii));
+  bitmap_ior_into (&ANTIC_IN (block)->values, &S->values);
+  bitmap_ior_into (&ANTIC_IN (block)->expressions, &S->expressions);
 
   /* clean (ANTIC_IN (block)) is defered to after the iteration converged
      because it can cause non-convergence, see for example PR81181.  */
 
   if (!bitmap_set_equal (old, ANTIC_IN (block)))
-    changed = true;
+    {
+      changed = true;
+      /* After the initial value set computation the value set may
+         only shrink during the iteration.  */
+      if (was_visited && flag_checking)
+	{
+	  bitmap_iterator bi;
+	  unsigned int i;
+	  EXECUTE_IF_AND_COMPL_IN_BITMAP (&ANTIC_IN (block)->values,
+					  &old->values, 0, i, bi)
+	    gcc_unreachable ();
+	}
+    }
 
  maybe_dump_sets:
   if (dump_file && (dump_flags & TDF_DETAILS))
@@ -2202,45 +2222,44 @@ compute_partial_antic_aux (basic_block block,
      VH.1 + 1 (VH.2), VH.2 + 1 (VH.3), etc), forever.  */
   else if (single_succ_p (block))
     {
-      basic_block succ = single_succ (block);
-      if (!(single_succ_edge (block)->flags & EDGE_DFS_BACK))
-	phi_translate_set (PA_OUT, PA_IN (succ), block, succ);
+      e = single_succ_edge (block);
+      if (!(e->flags & EDGE_DFS_BACK))
+	phi_translate_set (PA_OUT, PA_IN (e->dest), e);
     }
   /* If we have multiple successors, we take the union of all of
      them.  */
   else
     {
       size_t i;
-      basic_block bprime;
 
-      auto_vec<basic_block> worklist (EDGE_COUNT (block->succs));
+      auto_vec<edge> worklist (EDGE_COUNT (block->succs));
       FOR_EACH_EDGE (e, ei, block->succs)
 	{
 	  if (e->flags & EDGE_DFS_BACK)
 	    continue;
-	  worklist.quick_push (e->dest);
+	  worklist.quick_push (e);
 	}
       if (worklist.length () > 0)
 	{
-	  FOR_EACH_VEC_ELT (worklist, i, bprime)
+	  FOR_EACH_VEC_ELT (worklist, i, e)
 	    {
 	      unsigned int i;
 	      bitmap_iterator bi;
 
-	      FOR_EACH_EXPR_ID_IN_SET (ANTIC_IN (bprime), i, bi)
+	      FOR_EACH_EXPR_ID_IN_SET (ANTIC_IN (e->dest), i, bi)
 		bitmap_value_insert_into_set (PA_OUT,
 					      expression_for_id (i));
-	      if (!gimple_seq_empty_p (phi_nodes (bprime)))
+	      if (!gimple_seq_empty_p (phi_nodes (e->dest)))
 		{
 		  bitmap_set_t pa_in = bitmap_set_new ();
-		  phi_translate_set (pa_in, PA_IN (bprime), block, bprime);
+		  phi_translate_set (pa_in, PA_IN (e->dest), e);
 		  FOR_EACH_EXPR_ID_IN_SET (pa_in, i, bi)
 		    bitmap_value_insert_into_set (PA_OUT,
 						  expression_for_id (i));
 		  bitmap_set_free (pa_in);
 		}
 	      else
-		FOR_EACH_EXPR_ID_IN_SET (PA_IN (bprime), i, bi)
+		FOR_EACH_EXPR_ID_IN_SET (PA_IN (e->dest), i, bi)
 		  bitmap_value_insert_into_set (PA_OUT,
 						expression_for_id (i));
 	    }
@@ -3158,8 +3177,7 @@ do_pre_regular_insertion (basic_block block, basic_block dom)
 	      gcc_assert (!(pred->flags & EDGE_FAKE));
 	      bprime = pred->src;
 	      /* We are looking at ANTIC_OUT of bprime.  */
-	      eprime = phi_translate (expr, ANTIC_IN (block), NULL,
-				      bprime, block);
+	      eprime = phi_translate (expr, ANTIC_IN (block), NULL, pred);
 
 	      /* eprime will generally only be NULL if the
 		 value of the expression, translated
@@ -3315,8 +3333,7 @@ do_pre_partial_partial_insertion (basic_block block, basic_block dom)
 	      gcc_assert (!(pred->flags & EDGE_FAKE));
 	      bprime = pred->src;
 	      eprime = phi_translate (expr, ANTIC_IN (block),
-				      PA_IN (block),
-				      bprime, block);
+				      PA_IN (block), pred);
 
 	      /* eprime will generally only be NULL if the
 		 value of the expression, translated