re PR tree-optimization/84111 (Compile time hog w/ -O2)

	PR tree-optimization/84111
	* tree-ssa-loop-ivcanon.c (tree_unroll_loops_completely_1): Skip
	inner loops added during recursion, as they don't have up-to-date
	SSA form.

	* gcc.c-torture/compile/pr84111.c: New test.

From-SVN: r257188

gcc/ChangeLog

+2018-01-30  Richard Biener  <rguenther@suse.de>
+	    Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/84111
+	* tree-ssa-loop-ivcanon.c (tree_unroll_loops_completely_1): Skip
+	inner loops added during recursion, as they don't have up-to-date
+	SSA form.
+
 2018-01-30  Jan Hubicka  <hubicka@ucw.cz>
 
 	PR ipa/81360

gcc/testsuite/ChangeLog

+2018-01-30  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/84111
+	* gcc.c-torture/compile/pr84111.c: New test.
+
 2018-01-30  Jan Hubicka  <hubicka@ucw.cz>
 
 	PR ipa/83179

gcc/testsuite/gcc.c-torture/compile/pr84111.c

+/* PR tree-optimization/84111 */
+
+void
+foo (int x, int y, int z)
+{
+  int a = 0;
+  int *b = &x;
+
+  while (a < 1)
+    {
+      int c = y;
+      *b = x;
+ lab:
+      for (a = 0; a < 36; ++a)
+        {
+          *b = 0;
+          if (x != 0)
+            y = 0;
+          while (c < 1)
+	    ;
+        }
+    }
+  if (z < 33)
+    {
+      b = (int *) 0;
+      ++y;
+      ++z;
+      if (x / *b != 0)
+        goto lab;
+    }
+}

gcc/tree-ssa-loop-ivcanon.c

@@ -1373,13 +1373,17 @@ tree_unroll_loops_completely_1 (bool may_increase_size, bool unroll_outer,
   bool changed = false;
   struct loop *inner;
   enum unroll_level ul;
+  unsigned num = number_of_loops (cfun);
 
-  /* Process inner loops first.  */
+  /* Process inner loops first.  Don't walk loops added by the recursive
+     calls because SSA form is not up-to-date.  They can be handled in the
+     next iteration.  */
   for (inner = loop->inner; inner != NULL; inner = inner->next)
-    changed |= tree_unroll_loops_completely_1 (may_increase_size,
-					       unroll_outer, father_bbs,
-					       inner);
- 
+    if ((unsigned) inner->num < num)
+      changed |= tree_unroll_loops_completely_1 (may_increase_size,
+						 unroll_outer, father_bbs,
+						 inner);
+
   /* If we changed an inner loop we cannot process outer loops in this
      iteration because SSA form is not up-to-date.  Continue with
      siblings of outer loops instead.  */