Also rename float32x4 to f32x4

PostMVP.md

@@ -38,8 +38,8 @@ variables are not aliasable and thus allow more aggressive optimization.
 Support fixed-width SIMD vectors, initially only for 128-bit wide vectors as
 demonstrated in [PNaCl's SIMD][] and [SIMD.js][].
 
-SIMD adds new local types (e.g., `float32x4`) so it has to be part of the core
-semantics. SIMD operations (e.g., `float32x4.add`) could be either builtin
+SIMD adds new local types (e.g., `f32x4`) so it has to be part of the core
+semantics. SIMD operations (e.g., `f32x4.add`) could be either builtin
 operations (no different from `i32.add`) or exports of a builtin SIMD module.
 
   [PNaCl's SIMD]: https://developer.chrome.com/native-client/reference/pnacl-c-cpp-language-support#portable-simd-vectors