Add optimize-added-constants pass for lowMemoryUnused (#1169)

Author: MaxGraey

cli/asc.js

@@ -729,6 +729,13 @@ exports.main = function main(argv, options, callback) {
       } else {
         add("precompute");
       }
+      if (module.getLowMemoryUnused()) {
+        if (optimizeLevel >= 3 || shrinkLevel >= 1) {
+          add("optimize-added-constants-propagate");
+        } else {
+          add("optimize-added-constants");
+        }
+      }
       // this will be done later (1)
       // if (optimizeLevel >= 2 || shrinkLevel >= 2) {
       //   add("code-pushing");

src/compiler.ts

@@ -363,7 +363,7 @@ export class Compiler extends DiagnosticEmitter {
       this.memoryOffset = i64_new(options.memoryBase);
       module.setLowMemoryUnused(false);
     } else {
-      if (options.optimizeLevelHint >= 2 && !options.lowMemoryLimit) {
+      if (!options.lowMemoryLimit && options.optimizeLevelHint >= 2) {
         this.memoryOffset = i64_new(1024);
         module.setLowMemoryUnused(true);
       } else {