Why exceptions for error handling is so important

[deadalnix via Digitalmars-d]

On Monday, 12 January 2015 at 23:29:08 UTC, H. S. Teoh via 
Digitalmars-d wrote:
> On Mon, Jan 12, 2015 at 11:17:24PM +0000, deadalnix via 
> Digitalmars-d wrote:
>> On Monday, 12 January 2015 at 22:17:57 UTC, Walter Bright 
>> wrote:
>> >Yes, it does. Returning an int in EAX now becomes returning a 
>> >pair
>> >[EAX,EDX].
>> 
>> It is not that big of a deal, EDX is a trash register anyway 
>> if memory
>> serve, but then, it become very bad when it do not fit in 
>> register
>> anymore.
>
> On the contrary, it's an extremely big deal. Registers are a 
> rare
> resource, and allocating them for maximal usefulness is a major 
> issue in
> code optimization.
>

These are trash register. Meaning the callee can put whatever in 
them. The caller must consider them trashed after the call.

So no, it do NOT increase register pressure.