Re: [bug] gcc-4.[23] miscompiling causing networking to bugger up

[Kyle McMartin <kyle@mcmartin.ca>]

On Wed, May 28, 2008 at 07:37:14PM -0400, Carlos O'Donell wrote:
> On Wed, May 28, 2008 at 7:00 PM, Kyle McMartin <kyle@mcmartin.ca> wrote:
> > Building the kernel without optimization is very tetchy... if you can
> > guess what passes to remove, I can try... one of the optimization
> > effects that must go is DCE though, otherwise we'll have undefined
> > references to things (ie: kmalloc_too_much in a switch that should have
> > been eliminated except the constant case.)
> 
> You *need* to build the kernel with -fno-dce and -fno-tree-dce?
> Are you working around another compiler bug?
> 
> Take a look at the attached scripts I use.
> 
> ./o2list.sh > o2list.txt
> ./permute-options.sh o2list.txt > run.sh
> chmod u+x
> run.sh
> 
> Normally I can simply run the results on a target and
> know which is good and which is bad. Unfortunately
> you have to link each into a kernel and try to boot.
> 

Other way around... we *need* dce (but apparnetly not on this file)
because of inline constructs like

	switch (sizeof(some constant)) {
	1:
		blah;
	default:
		some_undefined_reference();
	}

Ah well, anyway, it works built at -O0, and buggers up at -O1.

Want a copy of each of the .S?