[LLVMdev] Overflow intrinsics

[Alastair Lynn]

Hello-

Over the past couple of days I've been writing some very basic  
optimisations in -instcombine for the arithmetic with overflow  
intrinsics. As Duncan Sands pointed out on IRC however, this is  
duplicated effort when one can get equivalent results using weird  
sizes of ints in the IR.

At present (at least, on x86/x86-64), the overflow intrinsics generate  
better code. So what would be the better route: keeping the overflow  
intrinsics, or getting rid of them and improving codegen to handle  
flags better?

Alastair