1 files changed, 1 insertions, 0 deletions
diff --git a/lib/compress.js b/lib/compress.js
index 442df59d..7c5558bd 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -2901,6 +2901,7 @@ merge(Compressor.prototype, {
             }
             if (isNaN(result)) return compressor.find_parent(AST_With) ? this : result;
             if (compressor.option("unsafe_math")
+                && result
                 && typeof result == "number"
                 && (this.operator == "+" || this.operator == "-")) {
                 var digits = Math.max(0, decimals(left), decimals(right));