optimize num >> num in js optimizer, necessary for asm now that we do not do shift optimization there

3 files changed, 15 insertions, 0 deletions

diff --git a/tools/js-optimizer.js b/tools/js-optimizer.js
index 634d7dda..efbfa8aa 100644
--- a/tools/js-optimizer.js
+++ b/tools/js-optimizer.js
@@ -486,6 +486,17 @@ function simplifyExpressionsPre(ast) {
         }
       }
     });
+
+    if (asm) {
+      // optimize num >> num, in asm we need this here since we do not run optimizeShifts
+      traverseGenerated(ast, function(node, type) {
+        if (type == 'binary' && node[1] == '>>' && node[2][0] == 'num' && node[3][0] == 'num') {
+          node[0] = 'num';
+          node[1] = node[2][1] >> node[3][1];
+          node.length = 2;
+        }
+      });
+    }
   }
 
   // The most common mathop is addition, e.g. in getelementptr done repeatedly. We can join all of those,
diff --git a/tools/test-js-optimizer-asm-pre-output.js b/tools/test-js-optimizer-asm-pre-output.js
index 84c95360..3437163e 100644
--- a/tools/test-js-optimizer-asm-pre-output.js
+++ b/tools/test-js-optimizer-asm-pre-output.js
@@ -4,6 +4,8 @@ function a() {
   f(347);
   f(351);
   f(8);
+  HEAP[1024] = 5;
+  HEAP[1024] = 5;
 }
 function b($this, $__n) {
   $this = $this | 0;
diff --git a/tools/test-js-optimizer-asm-pre.js b/tools/test-js-optimizer-asm-pre.js
index 3042ef66..42eb435a 100644
--- a/tools/test-js-optimizer-asm-pre.js
+++ b/tools/test-js-optimizer-asm-pre.js
@@ -4,6 +4,8 @@ function a() {
   f(347 | 0);
   f(347 | 12);
   f(347 & 12);
+  HEAP[4096 >> 2] = 5;
+  HEAP[(4096 & 8191) >> 2] = 5;
 }
 function b($this, $__n) {
   $this = $this | 0;