# HG changeset patch
# User rraghavan
# Date 1486111618 28800
# Node ID 685a262f474fb76d31d98cc0ad328db733632a3d
# Parent  b31dd7e27325507fa72024bd9d3cb98aae544ea3
8144484: assert(no_dead_loop) failed: dead loop detected
Summary: Bailout early without splitting Phi through memory merges if TOP inputs present for Phi Nodes
Reviewed-by: thartmann, kvn

diff -r b31dd7e27325 -r 685a262f474f hotspot/src/share/vm/opto/cfgnode.cpp
--- a/hotspot/src/share/vm/opto/cfgnode.cpp	Fri Feb 03 08:17:35 2017 +0100
+++ b/hotspot/src/share/vm/opto/cfgnode.cpp	Fri Feb 03 00:46:58 2017 -0800
@@ -1889,6 +1889,12 @@
     bool saw_self = false;
     for( uint i=1; i<req(); ++i ) {// For all paths in
       Node *ii = in(i);
+      // TOP inputs should not be counted as safe inputs because if the
+      // Phi references itself through all other inputs then splitting the
+      // Phi through memory merges would create dead loop at later stage.
+      if (ii == top) {
+        return NULL; // Delay optimization until graph is cleaned.
+      }
       if (ii->is_MergeMem()) {
         MergeMemNode* n = ii->as_MergeMem();
         merge_width = MAX2(merge_width, n->req());