Do not spill variables/registers on the stack

[Bob Plantz]

On 2/3/2011 3:58 AM, David Brown wrote:
> On 03/02/2011 10:56, Drasko DRASKOVIC wrote:
>> On Thu, Feb 3, 2011 at 10:42 AM, David Brown<david@westcontrol.com>  
>> wrote:
>>> My understanding is that "register" is ignored at -O1 and above, 
>>> which would
>>> seem to match your experience.
>>
>> You wanted to say "-O1 and below", right ?
>>
>
> No, "register" is ignored at -O1 and above.  When the optimiser is 
> enabled, /it/ decides whether data should go in a register, or has to 
> go on the stack, or can be eliminated entirely.  It is only at -O0 
> that the compiler puts everything on the stack by default, and puts 
> "register" data in registers.  That's why the "register" keyword has 
> been considered redundant for many years - the compiler almost always 
> does a much better job than any human at deciding what data to put in 
> registers.
>
Let us not forget that a human wrote the compiler. Ultimately, it is a human who makes these decisions. At least, I hope so. :-)

A little off topic here, but it bugs me when "customer service" tells me there was a "computer error." No, there was a programming error, which was made by a human.

--Bob