verify imul correctness, workaround for webkit bug 126345; closes #1991

1 files changed, 2 insertions, 1 deletions

diff --git a/src/preamble.js b/src/preamble.js
index f9fccdf6..ac6ee7b3 100644
--- a/src/preamble.js
+++ b/src/preamble.js
@@ -1090,7 +1090,8 @@ Module['writeAsciiToMemory'] = writeAsciiToMemory;
 {{{ reSign }}}
 
 #if PRECISE_I32_MUL
-if (!Math['imul']) Math['imul'] = function imul(a, b) {
+// check for imul support, and also for correctness ( https://bugs.webkit.org/show_bug.cgi?id=126345 )
+if (!Math['imul'] || Math['imul'](0xffffffff, 5) !== -5) Math['imul'] = function imul(a, b) {
   var ah  = a >>> 16;
   var al = a & 0xffff;
   var bh  = b >>> 16;