Christian Böhme 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.
