Try both ways to fold an add together. This allows us to generate this code

        imul %EAX, %EAX, 400
        add %ECX, %EAX
        add %ESI, DWORD PTR [%ECX + 4*%EDX]
        inc %EDX
        cmp %EDX, 100

instead of this:

        imul %EAX, %EAX, 400
        add %ECX, %EAX
        mov %EAX, %EDX
        shl %EAX, 2
        add %ECX, %EAX
        add %ESI, DWORD PTR [%ECX]
        inc %EDX
        cmp %EDX, 100

llvm-svn: 19513