Optimize alignment rounding.

Replace x>>2<<2 and x>>3<<3 with x&-4 and x&-8, respectively, since
an and is cheaper than two shifts.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/preamble.js b/src/preamble.js
index 183fd0c8..75519094 100644
--- a/src/preamble.js
+++ b/src/preamble.js
@@ -644,7 +644,7 @@ Module['stringToUTF32'] = stringToUTF32;
 
 var PAGE_SIZE = 4096;
 function alignMemoryPage(x) {
-  return ((x+4095)>>12)<<12;
+  return (x+4095)&-4096;
 }
 
 var HEAP;