Specialize min/max functions for GHC provided instances.

In particular for Int/Word/Float/Double we should aim to provide branchless code where reasonable.

Especially when using SSE we should just use minss instead of

  ucomisd %xmm1,%xmm0
  jp .Lc5vv
  jbe .Lc5vw

which is worse in all kinds of ways.

If someone feels like tackling this I'm happy to help with code review, answering questions, etc.

I won't get around to doing it myself any time soon.

As a starting point the instance declarations are in ghc-prim/GHC/Classes.hs.

I would look into solving this via adding a new MachOP/PrimOP but maybe there are even better ways.

Trac metadata

Trac field	Value
Version	8.4.3
Type	Task
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
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