Check for divide by zero.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@142640 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/utils/release/findRegressions.py b/utils/release/findRegressions.py
index 7629c8b..d3811a5 100755
--- a/utils/release/findRegressions.py
+++ b/utils/release/findRegressions.py
@@ -105,8 +105,8 @@
         elif not math.isnan(d_old[t][x]) and math.isnan(d_new[t][x]):
           print t + " *** REGRESSION (" + x + ")"
 
-        if d_new[t][x] > d_old[t][x] and \
-              (d_new[t][x] - d_old[t][x]) / d_new[t][x] > .05:
+        if d_new[t][x] > d_old[t][x] and d_old[t][x] > 0.0 and \
+              (d_new[t][x] - d_old[t][x]) / d_old[t][x] > .05:
           print t + " *** REGRESSION (" + x + ")"
 
     else :