On Thu, Jan 17, 2013 at 12:01 PM, Johan Tibell <johan.tib...@gmail.com> wrote: > I forgot I once raised this on the GHC bug tracker: > http://hackage.haskell.org/trac/ghc/ticket/7025 > > Here's what Simon M had to say back then: > > "The right thing is to put -msse in the cc-options field of your > .cabal file, if that's what you want. > > I'm distinctly uneasy about having -msse magically pass through to gcc. > > * There are many flags that we do not pass through to gcc, so having > one that we do pass through could be confusing (and lead to lots more > requests for more flags to be passed through) > > * What if there is a variant of -msse that gcc supports but we don't? > Wouldn't we have to keep them in sync? > > I'm going to close this as wontfix, but please feel free to reopen and > disagree."
One problem with having the user set cc-options in addition to passing -msse to GHC, is that the user might not realize that he/she needs to do this. This is bad if you use -fllvm, as your -msse will essentially just be ignored as the LLVM primitives we use in the LLVM backend (e.g. for popcnt) won't convert to SSE instructions. Even worse, LLVM doesn't support a -msse flag, instead you need to use -mattr=+sse, so the user needs to be aware of this difference and change his/her flags depending on if we use the native backend or the LLVM backend. -- Johan _______________________________________________ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
