Re: -O0 dead code

[Bruce Korb <bkorb at sco dot COM>]

Jeffrey A Law wrote:
> 
>   In message <20000808005643.A6080@cygnus.com>you write:
>   > So how do people feel about the notion of dead code elimination at -O0?
>   > If we exclude the bits that that detect dead stores, we shouldn't be
>   > affecting any user-visible state, since all user variables live in
>   > memory at -O0.
>   >
>   > It shouldn't (though I've not checked) take any more compile time than
>   > we're using now, since flow1 is used to collect lifetimes for register
>   > allocation.  Normal dead code elimination happens concurrent to that.
> Sounds good to me.  I've always been a believer in generating unoptimized
> code, not stupid code at -O0 :-)

It sounds good to me, IFF you can be sure to *not* eliminate
code that one would expect to see from a debugger.  If it is
possible that you would, then absolutely not.  (Or, "absoultely
not" in the absence of a compiler compile time flag that says
otherwise.  Don't we need another configurable option anyway?)