[GHC] #9136: Constant folding in Core could be better

[GHC]

#9136: Constant folding in Core could be better
--------------------------------------------+------------------------------
        Reporter:  simonpj                  |            Owner:
            Type:  bug                      |           Status:  new
        Priority:  normal                   |        Milestone:
       Component:  Compiler                 |          Version:  7.8.2
      Resolution:                           |         Keywords:
Operating System:  Unknown/Multiple         |     Architecture:
 Type of failure:  Runtime performance bug  |  Unknown/Multiple
       Test Case:                           |       Difficulty:  Unknown
        Blocking:                           |       Blocked By:
                                            |  Related Tickets:
--------------------------------------------+------------------------------

Comment (by nomeata):

 Care to explain?

 `(x +# y) -# z = x +# (y -# z)` looks very much like rewriting to me, and
 rewrite rules are a powerful mechanism for that. And if we were able to
 specify that declaratively in source code, instead of letting the compiler
 grow and grow, even better, I’d say.

 Also note that constant folding is also done with (built-in, more
 powerful) RULES already.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9136#comment:4>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler