X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Fcmm%2FCmmProcPoint.hs;h=aa0ef01d37fbd8575749da759f19e18c23ea4d57;hb=0d80489c9b9f2421f65d8dd86c1e50c6bb429715;hp=36c02ff810f02fc3ce1a863aad38f735d3afad60;hpb=a2d5d3c9677a740ace920a976d03dfbd82f7697b;p=ghc-hetmet.git

diff --git a/compiler/cmm/CmmProcPoint.hs b/compiler/cmm/CmmProcPoint.hs
index 36c02ff..aa0ef01 100644
--- a/compiler/cmm/CmmProcPoint.hs
+++ b/compiler/cmm/CmmProcPoint.hs
@@ -1,9 +1,17 @@
+{-# OPTIONS -w #-}
+-- The above warning supression flag is a temporary kludge.
+-- While working on this module you are encouraged to remove it and fix
+-- any warnings in the module. See
+--     http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings
+-- for details
+
 module CmmProcPoint (
   calculateProcPoints
   ) where
 
 #include "HsVersions.h"
 
+import BlockId
 import Cmm
 import CmmBrokenBlock
 import Dataflow
@@ -79,8 +87,12 @@ calculateNewProcPoints  owners block =
           where
             parent_owners = lookupWithDefaultUFM owners emptyUniqSet parent_id
             child_owners = lookupWithDefaultUFM owners emptyUniqSet child_id
-            needs_proc_point = not $ isEmptyUniqSet $
-                               child_owners `minusUniqSet` parent_owners
+            needs_proc_point =
+                -- only if parent isn't dead
+                (not $ isEmptyUniqSet parent_owners) &&
+                -- and only if child has more owners than parent
+                (not $ isEmptyUniqSet $
+                     child_owners `minusUniqSet` parent_owners)
 
 calculateOwnership :: BlockEnv BrokenBlock
                    -> UniqSet BlockId
@@ -113,4 +125,4 @@ calculateOwnership blocks_ufm proc_points blocks =
                   new = old `unionUniqSets`
                         lookupWithDefaultUFM owners emptyUniqSet cause'
 
-      unknown_block = panic "unknown BlockId in selectStackFormat"
+      unknown_block = panic "unknown BlockId in calculateOwnership"