[project @ 2000-06-18 08:37:17 by simonpj]

[ghc-hetmet.git] / ghc / compiler / main / Main.lhs

diff --git a/ghc/compiler/main/Main.lhs b/ghc/compiler/main/Main.lhs
index beb70cb..e9827b4 100644 (file)
--- a/ghc/compiler/main/Main.lhs
+++ b/ghc/compiler/main/Main.lhs
@@ -25,6 +25,7 @@ import MkIface                ( writeIface )
 import TcModule                ( TcResults(..), typecheckModule )
 import Desugar         ( deSugar )
 import SimplCore       ( core2core )
+import OccurAnal       ( occurAnalyseBinds )
 import CoreLint                ( endPass )
 import CoreUtils       ( coreBindsSize )
 import CoreTidy                ( tidyCorePgm )
@@ -156,7 +157,15 @@ doIt (core_cmds, stg_cmds)
     tidyCorePgm tidy_uniqs this_mod
                simplified orphan_rules                 >>= \ (tidy_binds, tidy_orphan_rules) -> 
 
-    coreBindsSize tidy_binds `seq`
+       -- Run the occurrence analyser one last time, so that
+       -- dead binders get dead-binder info.  This is exploited by
+       -- code generators to avoid spitting out redundant bindings.
+       -- The occurrence-zapping in Simplify.simplCaseBinder means
+       -- that the Simplifier nukes useful dead-var stuff especially
+       -- in case patterns.
+    let occ_anal_tidy_binds = occurAnalyseBinds tidy_binds in
+
+    coreBindsSize occ_anal_tidy_binds `seq`
 --     TEMP: the above call zaps some space usage allocated by the
 --     simplifier, which for reasons I don't understand, persists
 --     thoroughout code generation
@@ -167,7 +176,7 @@ doIt (core_cmds, stg_cmds)
     show_pass "Core2Stg"                       >>
     _scc_     "Core2Stg"
     let
-       stg_binds   = topCoreBindsToStg c2s_uniqs tidy_binds
+       stg_binds   = topCoreBindsToStg c2s_uniqs occ_anal_tidy_binds
     in
 
        --------------------------  Simplify STG code -------------------------------
@@ -184,7 +193,7 @@ doIt (core_cmds, stg_cmds)
     in
     writeIface this_mod old_iface new_iface
               local_tycons local_classes inst_info
-              final_ids tidy_binds tidy_orphan_rules           >>
+              final_ids occ_anal_tidy_binds tidy_orphan_rules          >>
 
 
        --------------------------  Code generation -------------------------------
@@ -201,7 +210,7 @@ doIt (core_cmds, stg_cmds)
     show_pass "CodeOutput"                             >>
     _scc_     "CodeOutput"
     codeOutput this_mod local_tycons local_classes
-              tidy_binds stg_binds2
+              occ_anal_tidy_binds stg_binds2
               c_code h_code abstractC 
               ncg_uniqs                                >>