[commit: ghc] supercompiler: Use localiseId when manufacturing Id for positive information (8cf2d73)

Repository : ssh://darcs.haskell.org//srv/darcs/ghc

On branch  : supercompiler

http://hackage.haskell.org/trac/ghc/changeset/8cf2d732f72bf50256cf3d50679136c0d60459a8

>---------------------------------------------------------------

commit 8cf2d732f72bf50256cf3d50679136c0d60459a8
Author: Max Bolingbroke <[email protected]>
Date:   Wed Mar 21 14:33:58 2012 +0000

    Use localiseId when manufacturing Id for positive information
    
    This prevents us creating some local bindings with external names, which
    messes up later simplifier runs

>---------------------------------------------------------------

 compiler/supercompile/Supercompile.hs             |    7 ++-----
 compiler/supercompile/Supercompile/Drive/Split.hs |    6 ++++--
 2 files changed, 6 insertions(+), 7 deletions(-)

diff --git a/compiler/supercompile/Supercompile.hs b/compiler/supercompile/Supercompile.hs
index 338c7e2..a378516 100644
--- a/compiler/supercompile/Supercompile.hs
+++ b/compiler/supercompile/Supercompile.hs
@@ -32,8 +32,6 @@ import MkCore     (mkWildValBinder)
 import Coercion   (isCoVar, mkCoVarCo, mkAxInstCo)
 import DataCon    (dataConAllTyVars, dataConRepArgTys, dataConTyCon, dataConWorkId)
 import VarSet
-import Name       (localiseName)
-import Var        (Var, varName, setVarName)
 import Id
 import MkId       (realWorldPrimId)
 import FastString (fsLit)
@@ -117,7 +115,8 @@ coreBindsToCoreTerm should_sc binds
     -- unique and b) the internality of these names will be carried down on the next simplifier run, so this works.
     -- The ice is thin, though!
     sc_xs = zappedBindersOfBinds sc_binds
-    internal_sc_binds = map (first localiseInternaliseId) sc_binds
+    -- NB: if we don't mark these Ids as not exported then we get lots of residual top-level bindings of the form x = y
+    internal_sc_binds = map (first localiseId) sc_binds
     -- Decide which things we should export from the supercompiled term using a Church tuple.
     -- We need to export to the top level of the module those bindings that are *any* of:
     --   1. Are exported by the module itself
@@ -130,8 +129,6 @@ coreBindsToCoreTerm should_sc binds
             exported_xs' = unionVarSets (map (S.idFreeVars . fst) exported')
     sc_xs_internal_xs = uncurry (go []) (partition (\(x, _) -> isExportedId x || x `elemVarSet` dont_sc_binds_fvs) (sc_xs `zip` zappedBindersOfBinds internal_sc_binds))
     sc_internal_xs = map snd sc_xs_internal_xs
-    localiseInternaliseId x = setIdNotExported (x `setVarName` localiseName (varName x))
-     -- If we don't mark these Ids as not exported then we get lots of residual top-level bindings of the form x = y
 
 
 -- NB: I can't see any GHC code that prevents nullary unboxed tuples, but I'm not actually sure they work
diff --git a/compiler/supercompile/Supercompile/Drive/Split.hs b/compiler/supercompile/Supercompile/Drive/Split.hs
index 21b4735..d356388 100644
--- a/compiler/supercompile/Supercompile/Drive/Split.hs
+++ b/compiler/supercompile/Supercompile/Drive/Split.hs
@@ -24,7 +24,7 @@ import Supercompile.StaticFlags
 import Supercompile.Utilities hiding (tails)
 
 import CoreUtils (filterAlts)
-import Id        (idUnique, idType, isDeadBinder, zapIdOccInfo)
+import Id        (idUnique, idType, isDeadBinder, zapIdOccInfo, localiseId)
 import Var       (varUnique)
 import PrelNames (undefinedName, wildCardKey)
 import Type      (splitTyConApp_maybe)
@@ -1120,7 +1120,9 @@ splitStackFrame ctxt_ids ids kf scruts bracketed_hole
                                                                                        Just scrut_v <- [altConToValue (idType x') (alt_rn, alt_con)]
                                                                                        let in_scrut_e@(_, scrut_e) = renamedTerm (fmap Value scrut_v)
                                                                                        scrut <- scruts'
-                                                                                       return (scrut, HB (howToBindCheap scrut_e) (Right in_scrut_e)))
+                                                                                       -- Localise the Id just in case this is the occurrence of a lambda-bound variable.
+                                                                                       -- We don't really want a Let-bound external name in the output!
+                                                                                       return (localiseId scrut, HB (howToBindCheap scrut_e) (Right in_scrut_e)))
                                                                         `M.union` M.fromList [(x, lambdaBound) | x <- x':alt_bvs]) -- NB: x' might be in scruts and union is left-biased
                                             alt_rns alt_cons alt_bvss -- NB: don't need to grab deeds for these just yet, due to the funny contract for transitiveInline
             alt_bvss = map altConBoundVars alt_cons'