Integer overflow and underflow semantics?

[Kagamin via Digitalmars-d]

On Thursday, 17 July 2014 at 11:56:24 UTC, David Nadlinger wrote:
> ---
> ; Function Attrs: nounwind readnone uwtable
> define i1 @_D4test3fooFiZb(i32 inreg %a_arg) #0 {
>   %tmp3 = icmp eq i32 %a_arg, 2147483647
>   ret i1 %tmp3
> }
> ---

Can't it simply generate code as is? Seems wasteful to spend 
compilation time on this.