(And Issue 4835 is about compile-time constants. CFFE is already plenty
slow, mostly because of memory allocations. Detecting overflow in
constants is not going to significantly slow down compilation, and it
has no effect on the runtime. Even GCC 4.3.4 performs such compile-time
tests.)
If CTFE did something different than real code, that would be a
problem. Again, you should be able to construct the needed types with a
struct, to use in both CTFE and real code.
Let me clarify that constants that are combined by default (even without
optimizations enabled), like the OP's example of 1024 * 1024 * 1024,
should be able to emit an error at compile time on overflow, or
automatically upgrade the type, I agree with that.
-Steve
