On x86 favors folding short immediate into some arithmetic operations (e.g. add,...

On x86 favors folding short immediate into some arithmetic operations (e.g. add, and, xor, etc.) because materializing an immediate in a register is expensive in turns of code size.
e.g.
movl 4(%esp), %eax
addl $4, %eax

is 2 bytes shorter than

movl $4, %eax
addl 4(%esp), %eax

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60139 91177308-0d34-0410-b5e6-96231b3b80d8