WebAssembly image dithering example

[kinke]

On Thursday, 2 August 2018 at 22:04:50 UTC, Allen Garvey wrote:
> 4. I was not able to use any of the optimization flags except 
> for enable inlining, since using any of them would optimize out 
> the entire program. I'm assuming this is because there is no 
> main function, so the compiler can't tell which functions are 
> actually being called.

I won't be able to run your full example (I'll keep my personal 
machine Node.js-free! ;)), so I just used `ldc2 
-mtriple=wasm32-unknown-unknown-wasm -betterC -O main.wasm` with 
current LDC master (and added the missing __assert stub).
The produced .wasm is 620 bytes small (without -O: 3,235 bytes); 
loading it in Firefox shows that the functions are there, here's 
an excerpt:

   (func $fillBayerMatrix (;3;) (param $var0 i32) (param $var1 i32)
     get_local $var1
     i64.const 4469670136257392600
     i64.store align=4
     get_local $var1
     i32.const 8
     i32.add
     i64.const -4753701902744867000
     i64.store align=4
   )
   (func $dither (;5;) (param $var0 i32) (param $var1 i32) (param 
$var2 i32) (param $var3 i32)
     get_local $var2
     i64.const 4469670136257392600
     i64.store align=4
     get_local $var2
     i32.const 8
     i32.add
     i64.const -4753701902744867000
     i64.store align=4
     block $label0
       get_local $var0
       get_local $var1
       i32.mul
       i32.const 2
       i32.shl
       i32.const 1
       i32.ge_s
       br_if $label0
       return
     end $label0
     unreachable
     unreachable
   )