On Monday, 28 July 2014 at 12:08:39 UTC, Daniel Murphy wrote:
"John Colvin" wrote in message
news:iguetbdxlyilavliz...@forum.dlang.org...
To what extent can a compiler use assertions? Can it work
backwards from an assert to affect previous code?
void foo(int a)
{
enforce(a & 1);
assert(a & 1);
}
The assert is dead code, because it will never be reached if (a
& 1) is false.
void bar()
{
assert(a & 1);
enforce(a & 1);
}
The throw inside enforce is dead code, because it will never be
reached if (a & 1) is false.
The compiler is free to remove dead code, because it doesn't
change the program's behaviour.
Ok. What about this:
int c;
void foo(int a)
{
if(a < 0) c++;
assert(a > 0);
}
I presume that cannot be optimised away entirely to:
void foo(int a) {}
?
