Micro-optimize access to emscripten_memcpy_big: moving return statement to wasm side saves 6 bytes (reduces JS code by 9 bytes, increases wasm code by only 3 bytes)

Author: juj

emscripten-version.txt

@@ -1 +1 @@
-"1.38.24"
+"1.38.25"

src/library.js

@@ -925,7 +925,6 @@ LibraryManager.library = {
 
   emscripten_memcpy_big: function(dest, src, num) {
     HEAPU8.set(HEAPU8.subarray(src, src+num), dest);
-    return dest;
   },
 
   memcpy__asm: true,
@@ -945,7 +944,8 @@ LibraryManager.library = {
       8192
 #endif
     ) {
-      return _emscripten_memcpy_big(dest|0, src|0, num|0)|0;
+      _emscripten_memcpy_big(dest|0, src|0, num|0)|0;
+      return dest|0;
     }
 
     ret = dest|0;

system/lib/libc/emscripten_memcpy.c

@@ -19,7 +19,8 @@ void *memcpy(void *restrict dest, const void *restrict src, size_t n)
   unsigned char *d_end;
 
   if (n >= 8192) {
-    return emscripten_memcpy_big(dest, src, n);
+    emscripten_memcpy_big(dest, src, n);
+    return dest;
   }
 
   d_end = d + n;