Canonicalize subtraction with constant on the right to addition (#3321)

Using addition in more places is better for gzip, and helps simplify the
optimizer as well.

Add a FinalOptimizer phase to do optimizations like our signed LEB tweaks, to
reduce binary size in the rare case when we do want a subtraction.

1 files changed, 2 insertions, 2 deletions

diff --git a/test/wasm2js/bulk-memory.2asm.js.opt b/test/wasm2js/bulk-memory.2asm.js.opt
index 77e682c41..4e6ccc529 100644
--- a/test/wasm2js/bulk-memory.2asm.js.opt
+++ b/test/wasm2js/bulk-memory.2asm.js.opt
@@ -180,7 +180,7 @@ for (var base64ReverseLookup = new Uint8Array(123/*'z'+1*/), i = 25; i >= 0; --i
       if (j < end) uint8Array[j++] = b1 << 4 | b2 >> 2;
       if (j < end) uint8Array[j++] = b2 << 6 | base64ReverseLookup[b64.charCodeAt(i+3)];
     }
-    return uint8Array; 
+    return uint8Array;
   }
   base64DecodeToExistingUint8Array(bufferView, 0, "qrvM3Q==");
 var retasmFunc = asmFunc(  { abort: function() { throw new Error('abort'); }
@@ -287,7 +287,7 @@ for (var base64ReverseLookup = new Uint8Array(123/*'z'+1*/), i = 25; i >= 0; --i
       if (j < end) uint8Array[j++] = b1 << 4 | b2 >> 2;
       if (j < end) uint8Array[j++] = b2 << 6 | base64ReverseLookup[b64.charCodeAt(i+3)];
     }
-    return uint8Array; 
+    return uint8Array;
   }
   memorySegments[0] = base64DecodeToExistingUint8Array(new Uint8Array(4), 0, "qrvM3Q==");
 var retasmFunc = asmFunc(  { abort: function() { throw new Error('abort'); }