(j3.2006) What do typical processors do?

[Keith Bierman]

> On Jul 18, 2017, at 6:33 PM, Van Snyder <Van.Snyder at jpl.nasa.gov> wrote:
> 
>> On Tue, 2017-07-18 at 23:30 +0000, Bill Long wrote:
>> I .....
> 
> CGEMM can be told to use the conjugate transpose of its first or second
> argument.  Maybe someday processors will recognize
> 
> C = matmul ( A, conjg(transpose(B)) )
> .....
> Would a processor recognize that and turn it into a call to CGEMM
> without creating temps?

Get the usage into a SPEC benchmark and processors will pattern match as appropriate.  Without sufficient proof it is worth the trouble .... Processors will probably not.  It isn't that it is hard, but there's almost always a virtually infinite list of transforms a compiler could do...And a pretty small number of people to do the work.