On 7/27/2013 1:57 AM, David Nadlinger wrote:
On Saturday, 27 July 2013 at 06:58:04 UTC, Walter Bright wrote:
Although it isn't in the spec, D should be "strict aliasing". This is because:
1. it enables better code generation
2. there are ways, such as unions, to get the other aliasing that doesn't
break strict aliasing
We need to carefully formalize this then, and quickly. The problem GCC, Clang
and others are facing is that (as you are probably aware) 2. isn't guaranteed to
work for type-casting pointers either by the specs, but people want to be able
to do this nonetheless.
Thus, they both accept pointer aliasing through union types, trying to optimize
as much as possible while avoiding to break people's expectations and existing
code. This is a very unfortunate situation for both compiler developers and
users; just search for something like "gcc strict aliasing" on StackOverflow for
examples.
There is already quite a lot of D code out there that violates the C-style
strict aliasing rules.
I agree. Want to do an enhancement request on bugzilla for it?
