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diff src/share/vm/opto/lcm.cpp @ 8691:571076d3c79d

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8009120: Fuzz instruction scheduling in HotSpot compilers Reviewed-by: kvn, vlivanov
author shade
date Tue, 05 Mar 2013 04:24:50 -0800
parents b30b3c2a0cf2
children 70120f47d403
line wrap: on
line diff
--- a/src/share/vm/opto/lcm.cpp	Mon Mar 04 13:15:01 2013 -0800
+++ b/src/share/vm/opto/lcm.cpp	Tue Mar 05 04:24:50 2013 -0800
@@ -421,6 +421,7 @@
   uint latency = 0; // Bigger is scheduled first
   uint score   = 0; // Bigger is better
   int idx = -1;     // Index in worklist
+  int cand_cnt = 0; // Candidate count
 
   for( uint i=0; i<cnt; i++ ) { // Inspect entire worklist
     // Order in worklist is used to break ties.
@@ -503,11 +504,14 @@
     uint n_score   = n->req();   // Many inputs get high score to break ties
 
     // Keep best latency found
-    if( choice < n_choice ||
-        ( choice == n_choice &&
-          ( latency < n_latency ||
-            ( latency == n_latency &&
-              ( score < n_score ))))) {
+    cand_cnt++;
+    if (choice < n_choice ||
+        (choice == n_choice &&
+         ((StressLCM && Compile::randomized_select(cand_cnt)) ||
+          (!StressLCM &&
+           (latency < n_latency ||
+            (latency == n_latency &&
+             (score < n_score))))))) {
       choice  = n_choice;
       latency = n_latency;
       score   = n_score;