re PR tree-optimization/84775 (ICE on valid code at -O3: in check_loop_closed_ssa_def, at tree-ssa-loop-manip.c:709)

2018-03-09  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/84775
	* tree-if-conv.c (add_bb_predicate_gimplified_stmts): Delink
	immediate uses of predicate stmts and mark them modified.

	Revert
	PR tree-optimization/84178
	* tree-if-conv.c (combine_blocks): Move insert_gimplified_predicates
	to caller.
	(version_loop_for_if_conversion): Delay update_ssa call.
	(tree_if_conversion): Delay update_ssa until after predicate
	insertion.

	* gcc.dg/torture/pr84775.c: New testcase.

From-SVN: r258387

4 files changed, 52 insertions, 9 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 69b7def..5b2f59b 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,17 @@
+2018-03-09  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/84775
+	* tree-if-conv.c (add_bb_predicate_gimplified_stmts): Delink
+	immediate uses of predicate stmts and mark them modified.
+
+	Revert
+	PR tree-optimization/84178
+	* tree-if-conv.c (combine_blocks): Move insert_gimplified_predicates
+	to caller.
+	(version_loop_for_if_conversion): Delay update_ssa call.
+	(tree_if_conversion): Delay update_ssa until after predicate
+	insertion.
+
 2018-03-09  Eric Botcazou  <ebotcazou@adacore.com>
 
 	PR target/84763
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index aadf998..de8b13f 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2018-03-09  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/84775
+	* gcc.dg/torture/pr84775.c: New testcase.
+
 2018-03-09  Jakub Jelinek  <jakub@redhat.com>
 
 	PR debug/84404
diff --git a/gcc/testsuite/gcc.dg/torture/pr84775.c b/gcc/testsuite/gcc.dg/torture/pr84775.c
new file mode 100644
index 0000000..bb9466b
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr84775.c
@@ -0,0 +1,18 @@
+/* { dg-do compile } */
+
+int a, b, c, d, e, f;
+
+void fn1 ()
+{
+  while (e)
+    for (f = 0; f < 4; f++)
+      {
+	int h[1];
+	for (; c; c++)
+	  if (a)
+	    break;
+	d = a - 4;
+	if (d)
+	  b = h[0];
+      }
+}
diff --git a/gcc/tree-if-conv.c b/gcc/tree-if-conv.c
index 59a0f1c..c68a0c7 100644
--- a/gcc/tree-if-conv.c
+++ b/gcc/tree-if-conv.c
@@ -257,6 +257,19 @@ set_bb_predicate_gimplified_stmts (basic_block bb, gimple_seq stmts)
 static inline void
 add_bb_predicate_gimplified_stmts (basic_block bb, gimple_seq stmts)
 {
+  /* We might have updated some stmts in STMTS via force_gimple_operand
+     calling fold_stmt and that producing multiple stmts.  Delink immediate
+     uses so update_ssa after loop versioning doesn't get confused for
+     the not yet inserted predicates.
+     ???  This should go away once we reliably avoid updating stmts
+     not in any BB.  */
+  for (gimple_stmt_iterator gsi = gsi_start (stmts);
+       !gsi_end_p (gsi); gsi_next (&gsi))
+    {
+      gimple *stmt = gsi_stmt (gsi);
+      delink_stmt_imm_use (stmt);
+      gimple_set_modified (stmt, true);
+    }
   gimple_seq_add_seq_without_update
     (&(((struct bb_predicate *) bb->aux)->predicate_gimplified_stmts), stmts);
 }
@@ -2371,6 +2384,7 @@ combine_blocks (struct loop *loop)
   edge_iterator ei;
 
   remove_conditions_and_labels (loop);
+  insert_gimplified_predicates (loop);
   predicate_all_scalar_phis (loop);
 
   if (any_pred_load_store)
@@ -2592,6 +2606,7 @@ version_loop_for_if_conversion (struct loop *loop)
   gsi = gsi_last_bb (cond_bb);
   gimple_call_set_arg (g, 1, build_int_cst (integer_type_node, new_loop->num));
   gsi_insert_before (&gsi, g, GSI_SAME_STMT);
+  update_ssa (TODO_update_ssa);
   return new_loop;
 }
 
@@ -2809,7 +2824,6 @@ tree_if_conversion (struct loop *loop)
   unsigned int todo = 0;
   bool aggressive_if_conv;
   struct loop *rloop;
-  bool need_update_ssa = false;
 
  again:
   rloop = NULL;
@@ -2855,7 +2869,6 @@ tree_if_conversion (struct loop *loop)
       struct loop *nloop = version_loop_for_if_conversion (vloop);
       if (nloop == NULL)
 	goto cleanup;
-      need_update_ssa = true;
       if (vloop != loop)
 	{
 	  /* If versionable_outer_loop_p decided to version the
@@ -2880,13 +2893,6 @@ tree_if_conversion (struct loop *loop)
 	}
     }
 
-  /* Due to hard to fix issues we end up with immediate uses recorded
-     for not yet inserted predicates which will confuse SSA update so
-     we delayed this from after versioning to after predicate insertion.  */
-  insert_gimplified_predicates (loop);
-  if (need_update_ssa)
-    update_ssa (TODO_update_ssa);
-
   /* Now all statements are if-convertible.  Combine all the basic
      blocks into one huge basic block doing the if-conversion
      on-the-fly.  */