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diff src/share/vm/opto/loopnode.cpp @ 22842:0a5d68482373

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8072753: Nondeterministic wrong answer on arithmetic Summary: Check for overflow when inverting the loop during the counted loop conversion Reviewed-by: kvn
author iveresov
date Tue, 17 Feb 2015 11:00:18 -0800
parents 78bbf4d43a14
children c1091733abe6
line wrap: on
line diff
--- a/src/share/vm/opto/loopnode.cpp	Tue Feb 17 19:59:05 2015 -0800
+++ b/src/share/vm/opto/loopnode.cpp	Tue Feb 17 11:00:18 2015 -0800
@@ -436,6 +436,19 @@
       return false; // cyclic loop or this loop trips only once
   }
 
+  if (phi_incr != NULL) {
+    // check if there is a possiblity of IV overflowing after the first increment
+    if (stride_con > 0) {
+      if (init_t->_hi > max_jint - stride_con) {
+        return false;
+      }
+    } else {
+      if (init_t->_lo < min_jint - stride_con) {
+        return false;
+      }
+    }
+  }
+
   // =================================================
   // ---- SUCCESS!   Found A Trip-Counted Loop!  -----
   //