Re: Live range splitting in new allocator

[Linus Torvalds <torvalds at transmeta dot com>]

On Mon, 29 Jan 2001 dewar@gnat.com wrote:

> <<So please at least consider breaking debugging.  It _will_ get fixed -
> too many people care about it.  But it should not get fixed by
> generating bad code.
> >>
> 
> It seems perfectly reasonable to me to take this attitude when optimization
> is turned on.

That's my personal opinion too, but gcc has long had the rule that the
presense or absense of "-g" should not affect code generation, only
debugging information. And too many people seem to think that "-O2 -g" is
a valid combination and should be debuggable.

Now _I_ personally think that "-O2 -g" is valid only for trying to find
compiler bugs, and that there might be some other switch for that. But I'm
probably in the minority - everybody else seems to love debuggers to
death.

(On the "debugging compiler" front, for example, I'd love to see an
assembly output mode where each instruction be tagged by the source line
it got inherited from. When combining instructions you'd select _one_ of
them - don't try to be correct, just try to be as helpful as you can be
without making the code worse. That would be cool, and would be a great
way to try to match up the output of two compiles that use different
scheduling etc)

		Linus