Integer overflow checking

[Walter Bright via Digitalmars-d]

On 4/12/2016 5:06 AM, Andrei Alexandrescu wrote:
> Interesting: http://blog.regehr.org/archives/1384 -- Andrei

Curiously never mentioned is the following optimization:

     return a+b*2+27;

becomes:

     LEA EAX,27[ESI][EDI*2]

To overflow check:

     ADD EDI,EDI
     JO overflow
     ADD EDI,27
     JO overflow
     MOV EAX,ESI
     ADD EAX,EDI
     JO overflow

I don't see efficiency there, even with the JO's being free.