Re: changing "configure" to default to "gcc -g -O2 -fwrapv ..."

[Bernd Schmidt]

Paul Eggert wrote:
> But so far, benchmark scores are the only scores given by the people
> who oppose having -O2 imply -fwrapv.

And you expect real-world results will be different because...?

> > You say you doubt it affects performance.  Based on what?  Facts
> > please, not guesses and hand-waiving...
>
> The burden of proof ought to be on the guys proposing -O2
> optimizations that break longstanding code, not on the skeptics.

IMHO the burden of proof should be on the people who are surprised that 
interesting things happen when they write in a language that isn't C and 
then try to pass it through a C compiler.

Has an example of code that actually breaks with a new gcc but not an 
old one been posted in this thread yet?  With -fstrict-aliasing we at 
least had examples of code that really broke with a new optimization 
before we disabled it (in the compiler, not in autoconf, mind you). 
Code got fixed, -fstrict-aliasing got enabled a release later, everyone 
moved on.


Bernd