On Friday 22 December 2006 02:06, Robert Dewar wrote:
> Paul Brook wrote:
> > On Friday 22 December 2006 00:58, Denis Vlasenko wrote:
> >> On Tuesday 19 December 2006 23:39, Denis Vlasenko wrote:
> >>> There are a lot of 100.00% safe optimizations which gcc
> &g
On Friday 22 December 2006 00:58, Denis Vlasenko wrote:
> On Tuesday 19 December 2006 23:39, Denis Vlasenko wrote:
> > There are a lot of 100.00% safe optimizations which gcc
> > can do. Value range propagation for bitwise operations, for one
>
> Or this, absolutely typical C code. i386 arch can co
On Tuesday 19 December 2006 22:39, Denis Vlasenko wrote:
> On Tuesday 19 December 2006 22:46, Paul Brook wrote:
> > > Compiler can optimize it any way it wants,
> > > as long as result is the same as unoptimized one.
> >
> > We have an option for that. It'
> Compiler can optimize it any way it wants,
> as long as result is the same as unoptimized one.
We have an option for that. It's called -O0.
Pretty much all optimization will change the behavior of your program. The
important distinction is whether that difference is observable in valid
progra
