--- icu/source/common/ubidi.c.orig	2014-12-19 10:23:38.103928414 +0000
+++ icu/source/common/ubidi.c	2014-12-19 10:26:58.370071527 +0000
@@ -2146,7 +2146,7 @@
     /* The isolates[] entries contain enough information to
        resume the bidi algorithm in the same state as it was
        when it was interrupted by an isolate sequence. */
-    if(dirProps[start]==PDI) {
+    if(dirProps[start]==PDI && pBiDi->isolateCount >= 0) {
         levState.startON=pBiDi->isolates[pBiDi->isolateCount].startON;
         start1=pBiDi->isolates[pBiDi->isolateCount].start1;
         stateImp=pBiDi->isolates[pBiDi->isolateCount].stateImp;
