[PATCH] Reorder Value and User fields to save 8 bytes of padding on 64-bit

[Rafael Ávila de Espíndola]

The sizes that I am seeing are

// patch
// 64: value=40 use=48
// 32: value=20 use=28

// master
// 64: value=40 use=56
// 32: value=20 use=28


So it is a saving of 8 bytes in Use. Value has the same size. Awesome!

http://reviews.llvm.org/D4073