[M3commit] CVS Update: cm3

[Tony Hosking]

I added it a long time back only because I saw failures with optimisation turned on.  Something to do with the alias analysis (and lack of proper type information) as far as I recall.


On 3 Jul 2010, at 20:44, Jay K wrote:

> 
> Tony, just to be clear..you/I are disturbed by volatile, but it has also, I believe, like always been there.
> It has been gone only very briefly, and its non-use is probably limited for other reasons (how many people are
> using it, on how many platforms?).
> 
> 
>  - Jay
> 
> ----------------------------------------
>> From: jay.krell at cornell.edu
>> To: hosking at cs.purdue.edu; jkrell at elego.de
>> CC: m3commit at elegosoft.com
>> Subject: RE: [M3commit] CVS Update: cm3
>> Date: Sun, 4 Jul 2010 00:42:20 +0000
>> 
>> 
>> Not a multiprocessor.
>>  Still interested in selective volatile?
>> 
>> 
>> This all bothers me too.
>> I don't want volatile. It makes the optimized code terrible.
>> But I don't want to debug any problem from removing it, beyond compilation failure.
>> 
>> 
>> I can try a few things.
>> This is all wierd. I swear I saw it hang several times.
>> I swear I'm trying to to change "too many" variables at a time. Yes, I know, 2 is too many.
>> 
>> 
>> Once I started getting version stamp mismatch, I resorted to using a cross built cm3.
>> Out of necessity sort of, but that causes more flucuation of variables.
>> 
>> Let me try again with volatile and see if it is solid.
>> Then I'll try with only volatile stores.
>> 
>> I've been trying optimized and unoptimized, and not kept good track of which when.
>> 
>> 
>> - Jay
>> 
>> 
>> ----------------------------------------
>>> From: hosking at cs.purdue.edu
>>> Date: Sat, 3 Jul 2010 20:36:20 -0400
>>> To: jkrell at elego.de
>>> CC: m3commit at elegosoft.com
>>> Subject: Re: [M3commit] CVS Update: cm3
>>> 
>>> I am very disturbed that volatile is needed here. Can we selectively turn it on for thread-critical files like ThreadPThread and see if it fixes the problem. I wonder if the double-checked locking is broken for PPC memory model. Is this on a multi-processor?
>>> 
>>> On 3 Jul 2010, at 12:57, Jay Krell wrote:
>>> 
>>>> CVSROOT: /usr/cvs
>>>> Changes by: jkrell at birch. 10/07/03 12:57:09
>>>> 
>>>> Modified files:
>>>> cm3/m3-sys/m3cc/gcc/gcc/m3cg/: parse.c
>>>> 
>>>> Log message:
>>>> restore volatile for powerpc and powerpc64 platforms
>>>> This seems to fix PPC_LINUX hanging.
>>>> This needs further debugging, but I'm not eager.
>>>> This will also affect PPC_DARWIN, PPC64_DARWIN, PPC32_OPENBSD,
>>>> PPC32_NETBSD, PPC32_FREEBSD, etc., but these platforms are little used or
>>>> nonexistant.
>>>> 
>>>> Having volatile like has been the very long standing situation though.
>>>> The result is that the optimizer does basically nothing.
>>> 
>> 
>