initial work on optimizeShifts pass in js optimizer

1 files changed, 21 insertions, 0 deletions

diff --git a/tools/test-js-optimizer-t2.js b/tools/test-js-optimizer-t2.js
new file mode 100644
index 00000000..f69e1aaf
--- /dev/null
+++ b/tools/test-js-optimizer-t2.js
@@ -0,0 +1,21 @@
+// TODO also with >> 1 and >> 3
+//      also HEAP*U*, and HEAP8, 16
+function shifty($id) {
+  // $id is a param, $id2 is a local. both should be replaced with a shifted version
+  q(HEAP32[$id >> 2]);
+  q(HEAP32[($id + 40) >> 2]);
+  q(HEAP32[($id + 80 | 0) >> 2]);
+  q(HEAP32[(unknown1 + unknown2 + $id) >> 2]);
+  q(HEAP32[(unknown1 + $id + unknown2) >> 2]); // unknowns should be shifted together
+  var localUnchanged1 = get(1), localUnchanged2 = get(1);
+  q(HEAP32[(localUnchanged1 + $id + localUnchanged2) >> 2]); // unknowns should be shifted together
+  q($id >> _something_); // non-fixed shift
+  q($id << _somethingElse_); // non-fixed shift
+  pause(-1);
+  var $id2;
+  $id2 = get(54);
+  q(HEAP32[$id2 >> 1]);
+  q(HEAP32[($id2 + 40) >> 1]);
+  q(HEAP32[($id2 + 80 | 0) >> 1]);
+}
+// EMSCRIPTEN_GENERATED_FUNCTIONS: ["shifty"]