remove unneeded outside |0 when a sequence ends in a safe bitop

3 files changed, 74 insertions, 2 deletions

diff --git a/tools/js-optimizer.js b/tools/js-optimizer.js
index c598fb81..57a3b1b3 100644
--- a/tools/js-optimizer.js
+++ b/tools/js-optimizer.js
@@ -402,6 +402,8 @@ function removeUnneededLabelSettings(ast) {
 
 // Various expression simplifications. Pre run before closure (where we still have metadata), Post run after.
 
+var USEFUL_BINARY_OPS = set('<<', '>>', '|', '&', '^');
+
 function simplifyExpressionsPre(ast) {
   // Look for (x&A)<<B>>B and replace it with X&A if possible.
   function simplifySignExtends(ast) {
@@ -427,7 +429,6 @@ function simplifyExpressionsPre(ast) {
   // 'useful' mathops already |0 anyhow.
 
   function simplifyBitops(ast) {
-    var USEFUL_BINARY_OPS = set('<<', '>>', '|', '&', '^');
     var SAFE_BINARY_OPS = set('+', '-', '*'); // division is unsafe as it creates non-ints in JS; mod is unsafe as signs matter so we can't remove |0's
     var ZERO = ['num', 0];
     var rerun = true;
@@ -538,6 +539,17 @@ function simplifyExpressionsPre(ast) {
             }
           }
         }
+      } else if (type == 'binary' && node[1] == '|') {
+        // canonicalize order of |0 to end
+        if (node[2][0] == 'num' && node[2][1] == 0) {
+          var temp = node[2];
+          node[2] = node[3];
+          node[3] = temp;
+        }
+        // if a seq ends in an |0, remove an external |0
+        if (node[2][0] == 'seq' && node[2][2][0] == 'binary' && node[2][2][1] in USEFUL_BINARY_OPS) {
+          return node[2];
+        }
       }
     });
 
diff --git a/tools/test-js-optimizer-asm-pre-output.js b/tools/test-js-optimizer-asm-pre-output.js
index 3257576e..a41ba2f8 100644
--- a/tools/test-js-optimizer-asm-pre-output.js
+++ b/tools/test-js-optimizer-asm-pre-output.js
@@ -8,6 +8,7 @@ function a() {
   HEAP[1024] = 5;
   whee(12, 13);
   whee(12, 13);
+  f((g = t(), g + g | 0));
 }
 function b($this, $__n) {
   $this = $this | 0;
@@ -131,4 +132,33 @@ function tempDoublePtr($45, $14, $28, $42) {
   func();
   HEAP32[4] = unelim2;
 }
+function boxx($this, $aabb, $xf, $childIndex) {
+  $this = $this | 0;
+  $aabb = $aabb | 0;
+  $xf = $xf | 0;
+  $childIndex = $childIndex | 0;
+  var $2 = +0, $4 = +0, $7 = +0, $9 = +0, $13 = +0, $14 = +0, $19 = +0, $20 = +0, $22 = +0, $25 = +0, $28 = +0, $32 = +0, $42 = +0, $45 = 0, $_sroa_06_0_insert_insert$1 = +0, $51 = 0, $_sroa_0_0_insert_insert$1 = +0;
+  $2 = +HEAPF32[$xf + 12 >> 2];
+  $4 = +HEAPF32[$this + 12 >> 2];
+  $7 = +HEAPF32[$xf + 8 >> 2];
+  $9 = +HEAPF32[$this + 16 >> 2];
+  $13 = +HEAPF32[$xf >> 2];
+  $14 = $13 + ($2 * $4 - $7 * $9);
+  $19 = +HEAPF32[$xf + 4 >> 2];
+  $20 = $4 * $7 + $2 * $9 + $19;
+  $22 = +HEAPF32[$this + 20 >> 2];
+  $25 = +HEAPF32[$this + 24 >> 2];
+  $28 = $13 + ($2 * $22 - $7 * $25);
+  $32 = $19 + ($7 * $22 + $2 * $25);
+  $42 = +HEAPF32[$this + 8 >> 2];
+  $45 = $aabb;
+  $_sroa_06_0_insert_insert$1 = +(($20 < $32 ? $20 : $32) - $42);
+  HEAPF32[$45 >> 2] = ($14 < $28 ? $14 : $28) - $42;
+  HEAPF32[$45 + 4 >> 2] = $_sroa_06_0_insert_insert$1;
+  $51 = $aabb + 8 | 0;
+  $_sroa_0_0_insert_insert$1 = +($42 + ($20 > $32 ? $20 : $32));
+  HEAPF32[$51 >> 2] = $42 + ($14 > $28 ? $14 : $28);
+  HEAPF32[$51 + 4 >> 2] = $_sroa_0_0_insert_insert$1;
+  return;
+}
 
diff --git a/tools/test-js-optimizer-asm-pre.js b/tools/test-js-optimizer-asm-pre.js
index efa73218..38487d2f 100644
--- a/tools/test-js-optimizer-asm-pre.js
+++ b/tools/test-js-optimizer-asm-pre.js
@@ -8,6 +8,7 @@ function a() {
   HEAP[(4096 & 8191) >> 2] = 5;
   whee(12, 13) | 0;
   +whee(12, 13);
+  f((g = t(), (g+g)|0)|0);
 }
 function b($this, $__n) {
   $this = $this | 0;
@@ -135,4 +136,33 @@ function tempDoublePtr($45, $14, $28, $42) {
   func();
   HEAPF32[4] = unelim2;
 }
-// EMSCRIPTEN_GENERATED_FUNCTIONS: ["a", "b", "rett", "ret2t", "retf", "i32_8", "tempDoublePtr"]
+function boxx($this, $aabb, $xf, $childIndex) {
+  $this = $this | 0;
+  $aabb = $aabb | 0;
+  $xf = $xf | 0;
+  $childIndex = $childIndex | 0;
+  var $2 = +0, $4 = +0, $7 = +0, $9 = +0, $13 = +0, $14 = +0, $19 = +0, $20 = +0, $22 = +0, $25 = +0, $28 = +0, $32 = +0, $42 = +0, $45 = 0, $_sroa_06_0_insert_insert$1 = 0, $51 = 0, $_sroa_0_0_insert_insert$1 = 0;
+  $2 = +HEAPF32[$xf + 12 >> 2];
+  $4 = +HEAPF32[$this + 12 >> 2];
+  $7 = +HEAPF32[$xf + 8 >> 2];
+  $9 = +HEAPF32[$this + 16 >> 2];
+  $13 = +HEAPF32[$xf >> 2];
+  $14 = $13 + ($2 * $4 - $7 * $9);
+  $19 = +HEAPF32[$xf + 4 >> 2];
+  $20 = $4 * $7 + $2 * $9 + $19;
+  $22 = +HEAPF32[$this + 20 >> 2];
+  $25 = +HEAPF32[$this + 24 >> 2];
+  $28 = $13 + ($2 * $22 - $7 * $25);
+  $32 = $19 + ($7 * $22 + $2 * $25);
+  $42 = +HEAPF32[$this + 8 >> 2];
+  $45 = $aabb;
+  $_sroa_06_0_insert_insert$1 = (HEAPF32[tempDoublePtr >> 2] = ($20 < $32 ? $20 : $32) - $42, HEAP32[tempDoublePtr >> 2] | 0) | 0;
+  HEAPF32[$45 >> 2] = ($14 < $28 ? $14 : $28) - $42;
+  HEAP32[$45 + 4 >> 2] = $_sroa_06_0_insert_insert$1;
+  $51 = $aabb + 8 | 0;
+  $_sroa_0_0_insert_insert$1 = (HEAPF32[tempDoublePtr >> 2] = $42 + ($20 > $32 ? $20 : $32), HEAP32[tempDoublePtr >> 2] | 0) | 0;
+  HEAPF32[$51 >> 2] = $42 + ($14 > $28 ? $14 : $28);
+  HEAP32[$51 + 4 >> 2] = $_sroa_0_0_insert_insert$1;
+  return;
+}
+// EMSCRIPTEN_GENERATED_FUNCTIONS: ["a", "b", "rett", "ret2t", "retf", "i32_8", "tempDoublePtr", "boxx"]