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Re: Integral conversions in C/C++
Christian BÃhme wrote:
> John Fine wrote:
>
>> But, if the machine has a 32bit by 32bit multiply that produces the
>> identical 64bit result, the optimizer is free to use it.
>
> Here's the catch:
>
> Optimizers aren't part of the standard. If the standard(s) were to
> allow for much more explicit expressions, many optimizers would do a
> much better job. Writing optimizers around standards is what since
> the 90ies characterizes ``good'' compilers. Here's where the kewl
> stuff happens.
>
> A strictly standard conforming C/C++ frontend would not (actually
> see the need to) propagate that information to the middle/back ends.
What ridiculous nonsense! Where in the definition of "strictly standard
conforming" does it forbid the propagation of such information?
Andrew.