GCC 3.3, GCC 3.4

[Mike Stump]

On Thursday, January 30, 2003, at 03:59 PM, Neil Booth wrote:
>> I detect the note of frustration, but I think this is an experiment
>> worth making.  Say, allow --with-gc=none (re-allow?) to choose 
>> ggc-none.c,
>> and see what happens.
>>
>> Perhaps the compiler need only turn on GC at all once a threshold 
>> number
>> of... something... has been passed.  (Statements?  Tree nodes created?
>> Dunno.)
>
> Whatever we do, the worst thing is to make GCC non-deterministic.
>
> Someone suggested this (Geoff?) and someone else (Mike I think!) 
> pointed
> out what a bad idea this was.

Scream now, as last I knew Geoff wanted to check the paging activity on 
the system to dynamically tune the number.  Last I knew, we planned a 
mode where one could get the deterministic results, though, 
unfortunately, if one wants to debug a problem, and when they ask for 
determinism, if the problem goes away, we are sol.  Geoff's contention 
I think is that this is unlikely, and that there should be few bugs of 
these sorts.  I'm happy to try it out and see, we can decide later if 
it really is a pain or not.

The biggest hit for me is, I must select the deterministic mode, as 
otherwise, I cannot breakpoint on address equality, which I like so 
very much.

I'm trying to envision the documentation:

--please-make-compiler-deterministic

	Eliminates non-determinism from the compiler.

:-)  It that an -f option, or an -m option?