On 12/8/2013 6:26 AM, qznc wrote:
On Sunday, 8 December 2013 at 12:35:45 UTC, ponce wrote:
1. D knows when data is immutable. C has to always make worst case
assumptions, and assume indirectly accessed data mutates.
ICC (and other C++ compilers) has plenty of way to disambiguate aliasing:
- a pragma to let the optimizer assume no loop dependency
- restrict keyword
- /Qalias-const: assumes a parameter of type pointer-to-const does not alias
with a parameter of type pointer-to-non-const.
- GCC-like strict aliasing rule
To be fair, all of these are unsafe optimizations. You only use them after
carefully identifying the hot spot. D immutability is based on a (probably)
sound type system and can be used without danger.
To be fairer (!), all of these (except restrict) are non-Standard extensions for
C. "restrict" is an extension for C++.
