X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2Fcmm%2FCmmContFlowOpt.hs;h=a3239b94a1dc5af6b50f30b9778d83d777173847;hp=320b1e78715c349f5d481ef95f87a51f49bc420a;hb=e6243a818496aad82b6f47511d3bd9bc800f747d;hpb=176fa33f17dd78355cc572e006d2ab26898e2c69 diff --git a/compiler/cmm/CmmContFlowOpt.hs b/compiler/cmm/CmmContFlowOpt.hs index 320b1e7..a3239b9 100644 --- a/compiler/cmm/CmmContFlowOpt.hs +++ b/compiler/cmm/CmmContFlowOpt.hs @@ -2,7 +2,7 @@ module CmmContFlowOpt ( runCmmOpts, cmmCfgOpts, cmmCfgOptsZ , branchChainElimZ, removeUnreachableBlocksZ, predMap - , replaceLabelsZ, runCmmContFlowOptsZs + , replaceLabelsZ, replaceBranches, runCmmContFlowOptsZs ) where @@ -19,7 +19,6 @@ import Outputable import Panic import Prelude hiding (unzip, zip) import Util -import UniqFM ------------------------------------ runCmmContFlowOptsZs :: [CmmZ] -> [CmmZ] @@ -31,7 +30,8 @@ cmmCfgOpts :: Tx (ListGraph CmmStmt) cmmCfgOptsZ :: Tx CmmGraph cmmCfgOpts = branchChainElim -- boring, but will get more exciting later -cmmCfgOptsZ = branchChainElimZ `seqTx` blockConcatZ `seqTx` removeUnreachableBlocksZ +cmmCfgOptsZ g = + (branchChainElimZ `seqTx` blockConcatZ `seqTx` removeUnreachableBlocksZ) g -- Here branchChainElim can ultimately be replaced -- with a more exciting combination of optimisations @@ -89,16 +89,19 @@ branchChainElimZ g@(G.LGraph eid args _) (lone_branch_blocks, others) = partitionWith isLoneBranchZ (G.to_block_list g) env = mkClosureBlockEnvZ lone_branch_blocks self_branches = - let loop_to (id, _) = - if lookup id == id then - Just (G.Block id Nothing (G.ZLast (G.mkBranchNode id))) - else - Nothing - in mapMaybe loop_to lone_branch_blocks + let loop_to (id, _) = + if lookup id == id then + Just (G.Block id emptyStackInfo (G.ZLast (G.mkBranchNode id))) + else + Nothing + in mapMaybe loop_to lone_branch_blocks lookup id = lookupBlockEnv env id `orElse` id +-- Be careful not to mark a block as a lone branch if it carries +-- important information about incoming arguments or the update frame. isLoneBranchZ :: CmmBlock -> Either (BlockId, BlockId) CmmBlock -isLoneBranchZ (G.Block id Nothing (G.ZLast (G.LastOther (LastBranch target)))) +isLoneBranchZ (G.Block id (StackInfo {argBytes = Nothing, returnOff = Nothing}) + (G.ZLast (G.LastOther (LastBranch target)))) | id /= target = Left (id,target) isLoneBranchZ other = Right other -- An infinite loop is not a link in a branch chain! @@ -107,27 +110,25 @@ replaceLabelsZ :: BlockEnv BlockId -> CmmGraph -> CmmGraph replaceLabelsZ env = replace_eid . G.map_nodes id middle last where replace_eid (G.LGraph eid off blocks) = G.LGraph (lookup eid) off blocks - middle m@(MidComment _) = m - middle (MidAssign r e) = MidAssign r (exp e) - middle (MidStore addr e) = MidStore (exp addr) (exp e) - middle (MidUnsafeCall tgt fs as) = MidUnsafeCall (midcall tgt) fs (map exp as) - middle (MidAddToContext e es) = MidAddToContext (exp e) (map exp es) - last (LastBranch id) = LastBranch (lookup id) - last (LastCondBranch e ti fi) = LastCondBranch (exp e) (lookup ti) (lookup fi) - last (LastSwitch e tbl) = LastSwitch (exp e) (map (fmap lookup) tbl) - last (LastCall tgt mb_id s) = LastCall (exp tgt) (fmap lookup mb_id) s - last (LastJump e s) = LastJump (exp e) s - last (LastReturn s) = LastReturn s - midcall (ForeignTarget e c) = ForeignTarget (exp e) c - midcall m@(PrimTarget _) = m - exp e@(CmmLit _) = e - exp (CmmLoad addr ty) = CmmLoad (exp addr) ty - exp e@(CmmReg _) = e - exp (CmmMachOp op es) = CmmMachOp op $ map exp es - exp e@(CmmRegOff _ _) = e + middle = mapExpDeepMiddle exp + last l = mapExpDeepLast exp (last' l) + last' (LastBranch bid) = LastBranch (lookup bid) + last' (LastCondBranch p t f) = LastCondBranch p (lookup t) (lookup f) + last' (LastSwitch e arms) = LastSwitch e (map (liftM lookup) arms) + last' (LastCall t k a r) = LastCall t (liftM lookup k) a r + exp (CmmLit (CmmBlock bid)) = CmmLit (CmmBlock (lookup bid)) exp (CmmStackSlot (CallArea (Young id)) i) = CmmStackSlot (CallArea (Young (lookup id))) i - exp e@(CmmStackSlot _ _) = e + exp e = e + lookup id = fmap lookup (lookupBlockEnv env id) `orElse` id + +replaceBranches :: BlockEnv BlockId -> CmmGraph -> CmmGraph +replaceBranches env g = map_nodes id id last g + where + last (LastBranch id) = LastBranch (lookup id) + last (LastCondBranch e ti fi) = LastCondBranch e (lookup ti) (lookup fi) + last (LastSwitch e tbl) = LastSwitch e (map (fmap lookup) tbl) + last l@(LastCall {}) = l lookup id = fmap lookup (lookupBlockEnv env id) `orElse` id ---------------------------------------------------------------- @@ -146,35 +147,38 @@ predMap g = G.fold_blocks add_preds emptyBlockEnv g -- find the back edges -- Order matters, so we work bottom up (reverse postorder DFS). -- -- To ensure correctness, we have to make sure that the BlockId of the block --- we are about to eliminate is not named in another instruction --- (except an adjacent stack pointer adjustment, which we expect and also eliminate). --- For +-- we are about to eliminate is not named in another instruction. -- -- Note: This optimization does _not_ subsume branch chain elimination. blockConcatZ :: Tx CmmGraph blockConcatZ = removeUnreachableBlocksZ `seqTx` blockConcatZ' blockConcatZ' :: Tx CmmGraph blockConcatZ' g@(G.LGraph eid off blocks) = - tx $ pprTrace "concatMap" (ppr concatMap) $ replaceLabelsZ concatMap $ G.LGraph eid off blocks' + tx $ replaceLabelsZ concatMap $ G.LGraph eid off blocks' where (changed, blocks', concatMap) = foldr maybe_concat (False, blocks, emptyBlockEnv) $ G.postorder_dfs g maybe_concat b@(G.Block bid _ _) (changed, blocks', concatMap) = let unchanged = (changed, extendBlockEnv blocks' bid b, concatMap) in case G.goto_end $ G.unzip b of (h, G.LastOther (LastBranch b')) -> - if num_preds b' == 1 then + if canConcatWith b' then (True, extendBlockEnv blocks' bid $ splice blocks' h b', extendBlockEnv concatMap b' bid) else unchanged _ -> unchanged num_preds bid = liftM sizeBlockSet (lookupBlockEnv backEdges bid) `orElse` 0 + canConcatWith b' = + case lookupBlockEnv blocks b' of + Just (G.Block _ (StackInfo {returnOff = Nothing}) _) -> num_preds b' == 1 + _ -> False backEdges = predMap g splice blocks' h bid' = case lookupBlockEnv blocks' bid' of - Just (G.Block _ Nothing t) -> G.zip $ G.ZBlock h t - Just (G.Block _ (Just _) _) -> + Just (G.Block _ (StackInfo {returnOff = Nothing}) t) -> + G.zip $ G.ZBlock h t + Just (G.Block _ _ _) -> panic "trying to concatenate but successor block has incoming args" - Nothing -> panic "unknown successor block" + Nothing -> pprPanic "unknown successor block" (ppr bid' <+> ppr blocks' <+> ppr blocks) tx = if changed then aTx else noTx ---------------------------------------------------------------- mkClosureBlockEnv :: [(BlockId, BlockId)] -> BlockEnv BlockId @@ -194,6 +198,6 @@ mkClosureBlockEnvZ blocks = mkBlockEnv $ map follow blocks ---------------------------------------------------------------- removeUnreachableBlocksZ :: Tx CmmGraph removeUnreachableBlocksZ g@(G.LGraph id off blocks) = - if length blocks' < sizeUFM blocks then aTx $ G.of_block_list id off blocks' - else noTx g + if length blocks' < sizeBEnv blocks then aTx $ G.of_block_list id off blocks' + else noTx g where blocks' = G.postorder_dfs g