[tree-ssa] Speeding things up

[Mike Stump]

On Wednesday, January 29, 2003, at 04:14 PM, law@redhat.com wrote:
>   In all we're talking about over 2.6 billion function calls (and this 
> is
>   *after* the algorithmic improvements).  For reference we really
>   need about 100k calls total.

Do you have timings for this?  13.98s -> 13.97s might not be worth 
making the code less clean, but 13.98s -> 5.32s I think is worthwhile.  
In some of my benchmarking, I've discovered that 100% of the code in 
entire files is not worth speeding up, as 100% of the time is spent on 
one line.

I think we have to be willing to make the code slightly less clean for 
the right performance enhancement.  Ideally, if people can find ways to 
get us the performance, without making the code any less readable, 
clean, maintainable, that would be great, but, failing that, we should 
entertain changes like this.  It all comes down to, how much worse is 
the code, and what is the benefit gained.

I'll submit my own changes that enhance performance, that also test 
this question.