mkConApp,
varToCoreExpr,
- bindersOf, bindersOfBinds, rhssOfBind, rhssOfAlts, isTyVar, isId,
+ isTyVar, isId,
+ bindersOf, bindersOfBinds, rhssOfBind, rhssOfAlts,
collectBinders, collectTyBinders, collectValBinders, collectTyAndValBinders,
collectArgs, collectBindersIgnoringNotes,
coreExprCc,
flattenBinds,
- isValArg, isTypeArg, valArgCount, valBndrCount,
+ isValArg, isTypeArg, valArgCount, valBndrCount, isRuntimeArg, isRuntimeVar,
-- Unfoldings
Unfolding(..), UnfoldingGuidance(..), -- Both abstract everywhere but in CoreUnfold.lhs
noUnfolding, mkOtherCon,
unfoldingTemplate, maybeUnfoldingTemplate, otherCons,
isValueUnfolding, isEvaldUnfolding, isCheapUnfolding, isCompulsoryUnfolding,
- hasUnfolding, hasSomeUnfolding,
+ hasUnfolding, hasSomeUnfolding, neverUnfold,
-- Seq stuff
seqRules, seqExpr, seqExprs, seqUnfolding,
-- Annotated expressions
- AnnExpr, AnnExpr'(..), AnnBind(..), AnnAlt, deAnnotate, deAnnotate',
+ AnnExpr, AnnExpr'(..), AnnBind(..), AnnAlt,
+ deAnnotate, deAnnotate', deAnnAlt,
-- Core rules
CoreRules(..), -- Representation needed by friends
CoreRule(..), -- CoreSubst, CoreTidy, CoreFVs, PprCore only
+ IdCoreRule,
RuleName,
emptyCoreRules, isEmptyCoreRules, rulesRhsFreeVars, rulesRules,
isBuiltinRule
#include "HsVersions.h"
+import CmdLineOpts ( opt_RuntimeTypes )
import CostCentre ( CostCentre, noCostCentre )
-import Var ( Var, Id, TyVar, isTyVar, isId, idType )
-import Type ( Type, UsageAnn, mkTyVarTy, isUnLiftedType, seqType )
-import Literal ( Literal(MachStr), mkMachInt )
+import Var ( Var, Id, TyVar, isTyVar, isId )
+import Type ( Type, mkTyVarTy, seqType )
+import Literal ( Literal, mkMachInt )
import DataCon ( DataCon, dataConId )
import VarSet
import Outputable
| Lam b (Expr b)
| Let (Bind b) (Expr b)
| Case (Expr b) b [Alt b] -- Binder gets bound to value of scrutinee
- -- DEFAULT case must be last, if it occurs at all
+ -- DEFAULT case must be *first*, if it occurs at all
| Note Note (Expr b)
| Type Type -- This should only show up at the top
-- level of an Arg
| InlineMe -- Instructs simplifer to treat the enclosed expression
-- as very small, and inline it at its call sites
- | TermUsg -- A term-level usage annotation
- UsageAnn -- (should not be a variable except during UsageSP inference)
+-- NOTE: we also treat expressions wrapped in InlineMe as
+-- 'cheap' and 'dupable' (in the sense of exprIsCheap, exprIsDupable)
+-- What this means is that we obediently inline even things that don't
+-- look like valuse. This is sometimes important:
+-- {-# INLINE f #-}
+-- f = g . h
+-- Here, f looks like a redex, and we aren't going to inline (.) because it's
+-- inside an INLINE, so it'll stay looking like a redex. Nevertheless, we
+-- should inline f even inside lambdas. In effect, we should trust the programmer.
\end{code}
+INVARIANTS:
+
+* The RHS of a letrec, and the RHSs of all top-level lets,
+ must be of LIFTED type.
+
+* The RHS of a let, may be of UNLIFTED type, but only if the expression
+ is ok-for-speculation. This means that the let can be floated around
+ without difficulty. e.g.
+ y::Int# = x +# 1# ok
+ y::Int# = fac 4# not ok [use case instead]
+
+* The argument of an App can be of any type.
+
+* The simplifier tries to ensure that if the RHS of a let is a constructor
+ application, its arguments are trivial, so that the constructor can be
+ inlined vigorously.
+
%************************************************************************
%* *
\begin{code}
type RuleName = FAST_STRING
+type IdCoreRule = (Id,CoreRule) -- Rules don't have their leading Id inside them
data CoreRule
= Rule RuleName
hasSomeUnfolding :: Unfolding -> Bool
hasSomeUnfolding NoUnfolding = False
hasSomeUnfolding other = True
+
+neverUnfold :: Unfolding -> Bool
+neverUnfold NoUnfolding = True
+neverUnfold (OtherCon _) = True
+neverUnfold (CoreUnfolding _ _ _ _ UnfoldNever) = True
+neverUnfold other = False
\end{code}
type CoreArg = Arg CoreBndr
type CoreBind = Bind CoreBndr
type CoreAlt = Alt CoreBndr
-type CoreNote = Note
\end{code}
Binders are ``tagged'' with a \tr{t}:
\end{code}
+
%************************************************************************
%* *
\subsection{Predicates}
%* *
%************************************************************************
+@isRuntimeVar v@ returns if (Lam v _) really becomes a lambda at runtime,
+i.e. if type applications are actual lambdas because types are kept around
+at runtime.
+
+Similarly isRuntimeArg.
+
+\begin{code}
+isRuntimeVar :: Var -> Bool
+isRuntimeVar | opt_RuntimeTypes = \v -> True
+ | otherwise = \v -> isId v
+
+isRuntimeArg :: CoreExpr -> Bool
+isRuntimeArg | opt_RuntimeTypes = \e -> True
+ | otherwise = \e -> isValArg e
+\end{code}
+
\begin{code}
isValArg (Type _) = False
isValArg other = True
deAnnotate' (AnnCase scrut v alts)
= Case (deAnnotate scrut) v (map deAnnAlt alts)
- where
- deAnnAlt (con,args,rhs) = (con,args,deAnnotate rhs)
+
+deAnnAlt :: AnnAlt bndr annot -> Alt bndr
+deAnnAlt (con,args,rhs) = (con,args,deAnnotate rhs)
\end{code}