diff options
Diffstat (limited to 'compiler/GHC/Core/Unfold.hs')
| -rw-r--r-- | compiler/GHC/Core/Unfold.hs | 28 |
1 files changed, 14 insertions, 14 deletions
diff --git a/compiler/GHC/Core/Unfold.hs b/compiler/GHC/Core/Unfold.hs index 6316e321d4..7786f2e3a2 100644 --- a/compiler/GHC/Core/Unfold.hs +++ b/compiler/GHC/Core/Unfold.hs @@ -47,8 +47,8 @@ import GHC.Core.DataCon import GHC.Types.Literal import GHC.Builtin.PrimOps import GHC.Types.Id.Info -import GHC.Types.Basic ( Arity ) import GHC.Types.RepType ( isZeroBitTy ) +import GHC.Types.Basic ( Arity, RecFlag(..) ) import GHC.Core.Type import GHC.Builtin.Names import GHC.Data.Bag @@ -1003,7 +1003,7 @@ nonTriv _ = True data CallCtxt = BoringCtxt - | RhsCtxt -- Rhs of a let-binding; see Note [RHS of lets] + | RhsCtxt RecFlag -- Rhs of a let-binding; see Note [RHS of lets] | DiscArgCtxt -- Argument of a function with non-zero arg discount | RuleArgCtxt -- We are somewhere in the argument of a function with rules @@ -1018,7 +1018,7 @@ instance Outputable CallCtxt where ppr CaseCtxt = text "CaseCtxt" ppr ValAppCtxt = text "ValAppCtxt" ppr BoringCtxt = text "BoringCtxt" - ppr RhsCtxt = text "RhsCtxt" + ppr (RhsCtxt ir)= text "RhsCtxt" <> parens (ppr ir) ppr DiscArgCtxt = text "DiscArgCtxt" ppr RuleArgCtxt = text "RuleArgCtxt" @@ -1244,21 +1244,17 @@ tryUnfolding logger opts !case_depth id lone_variable = case cont_info of CaseCtxt -> not (lone_variable && is_exp) -- Note [Lone variables] ValAppCtxt -> True -- Note [Cast then apply] - RuleArgCtxt -> uf_arity > 0 -- See Note [Unfold into lazy contexts] + RuleArgCtxt -> uf_arity > 0 -- See Note [RHS of lets] DiscArgCtxt -> uf_arity > 0 -- Note [Inlining in ArgCtxt] - RhsCtxt -> uf_arity > 0 -- + RhsCtxt NonRecursive + -> uf_arity > 0 -- See Note [RHS of lets] _other -> False -- See Note [Nested functions] -{- -Note [Unfold into lazy contexts] -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -Merged into Note [RHS of lets]. - -Note [RHS of lets] -~~~~~~~~~~~~~~~~~~ +{- Note [RHS of lets] +~~~~~~~~~~~~~~~~~~~~~ When the call is the argument of a function with a RULE, or the RHS of a let, -we are a little bit keener to inline. For example +we are a little bit keener to inline (in tryUnfolding). For example f y = (y,y,y) g y = let x = f y in ...(case x of (a,b,c) -> ...) ... We'd inline 'f' if the call was in a case context, and it kind-of-is, @@ -1267,7 +1263,11 @@ only we can't see it. Also could be expensive whereas x = case v of (a,b) -> a is patently cheap and may allow more eta expansion. -So we treat the RHS of a let as not-totally-boring. + +So, in `interesting_call` in `tryUnfolding`, we treat the RHS of a +/non-recursive/ let as not-totally-boring. A /recursive/ let isn't +going be inlined so there is much less point. Hence the (only reason +for the) RecFlag in RhsCtxt Note [Unsaturated applications] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |