Should the comma operator be removed in D2?

[Robert Jacques]

On Wed, 18 Nov 2009 06:34:59 -0500, retard <re at tard.com.invalid> wrote:

> Tue, 17 Nov 2009 20:23:35 -0500, Robert Jacques wrote:
>
>> Also, all those well
>> known optimizations don't magically work for structs: I've seen modern
>> compilers do some pretty stupid things when structs and temporary values
>> are involved.
>
> Are you talking about dmc/dmd now? Have you tried gcc 4.4 or 4.5, llvm
> dev version or latest visual c++ ? Temporary values are often used with
> e.g. expression templates and the compilers have generated decently
> performing code for ages now. dmd is the only stupid compiler which
> cannot inline e.g. expression templates for matrix operations.

The bug I'm thinking of was in the Open64 compiler, and I think it's been  
squashed now. But this happened in the last 2-3 years, and only was caught  
because a major vendor really stressed the performance of struct  
operations on a particular backend. (Nvidia and GPUs) The point, is that  
the actual optimization rules in the compiler for free variables and for  
structs are sometimes completely separate entities. It doesn't mean it  
can't be done, it just means it might have to be coded. Basically, Tuples  
introduce a level of obfuscation, which might (or might not) hamper the  
current optimizer.