On Friday, 29 August 2014 at 02:10:55 UTC, ketmar via
Digitalmars-d wrote:
On Thu, 28 Aug 2014 09:12:15 +0000
deadalnix via Digitalmars-d <[email protected]> wrote:
It forces all the load to potentially have side effects,
which, in turn, limit dramatically what the optimizer can do.
but there is alot code that doesn't need "super-speed". it's ok
to
fallback to "standard C" for the parts that need all speed we
can have
w/o assembly. but most programs are ok with not-so-extensive
optimizations, and writing code in "friendly c" is much easier
than in
"standard c".
i myself compiling all my C code with -fwrapv
-fno-strict-aliasing
-fno-delete-null-pointer-checks. i believe that compiler was
made to
make my life easier, not to make it harder. so it's the
compiler who
should obey my orders, not vice versa. ;-)
It is not only about null checks.
If the value in unspecified, rather than the behavior undefined,
it means that no load or store can be optimized away or
reordered, unless the compiler can prove that is won't fault.
I'm talking about doubtful optimization to gain 0.5% here, but
that everything single variable except locals must be considered
volatile in the C sense.
