diff options
Diffstat (limited to 'compiler/codeGen')
| -rw-r--r-- | compiler/codeGen/StgCmmUtils.hs | 29 |
1 files changed, 23 insertions, 6 deletions
diff --git a/compiler/codeGen/StgCmmUtils.hs b/compiler/codeGen/StgCmmUtils.hs index 5e8944df4a..763177f297 100644 --- a/compiler/codeGen/StgCmmUtils.hs +++ b/compiler/codeGen/StgCmmUtils.hs @@ -652,14 +652,21 @@ emitCmmLitSwitch scrut branches deflt = do join_lbl <- newLabelC deflt_lbl <- label_code join_lbl deflt branches_lbls <- label_branches join_lbl branches - emit =<< mk_lit_switch scrut' deflt_lbl + emit =<< mk_lit_switch scrut' deflt_lbl noBound (sortBy (comparing fst) branches_lbls) emitLabel join_lbl +-- | lower bound (inclusive), upper bound (exclusive) +type LitBound = (Maybe Literal, Maybe Literal) + +noBound :: LitBound +noBound = (Nothing, Nothing) + mk_lit_switch :: CmmExpr -> BlockId + -> LitBound -> [(Literal,BlockId)] -> FCode CmmAGraph -mk_lit_switch scrut deflt [(lit,blk)] +mk_lit_switch scrut deflt bounds [(lit,blk)] = do dflags <- getDynFlags let @@ -667,12 +674,19 @@ mk_lit_switch scrut deflt [(lit,blk)] cmm_ty = cmmLitType dflags cmm_lit rep = typeWidth cmm_ty ne = if isFloatType cmm_ty then MO_F_Ne rep else MO_Ne rep - return (mkCbranch (CmmMachOp ne [scrut, CmmLit cmm_lit]) deflt blk) -mk_lit_switch scrut deflt_blk_id branches + return $ if lit `onlyWithinBounds'` bounds + then mkBranch blk + else mkCbranch (CmmMachOp ne [scrut, CmmLit cmm_lit]) deflt blk + where + -- If the bounds already imply scrut == lit, then we can skip the final check (#10129) + l `onlyWithinBounds'` (Just lo, Just hi) = l `onlyWithinBounds` (lo, hi) + l `onlyWithinBounds'` _ = False + +mk_lit_switch scrut deflt_blk_id (lo_bound, hi_bound) branches = do dflags <- getDynFlags - lo_blk <- mk_lit_switch scrut deflt_blk_id lo_branches - hi_blk <- mk_lit_switch scrut deflt_blk_id hi_branches + lo_blk <- mk_lit_switch scrut deflt_blk_id bounds_lo lo_branches + hi_blk <- mk_lit_switch scrut deflt_blk_id bounds_hi hi_branches mkCmmIfThenElse (cond dflags) lo_blk hi_blk where n_branches = length branches @@ -682,6 +696,9 @@ mk_lit_switch scrut deflt_blk_id branches (lo_branches, hi_branches) = span is_lo branches is_lo (t,_) = t < mid_lit + bounds_lo = (lo_bound, Just mid_lit) + bounds_hi = (Just mid_lit, hi_bound) + cond dflags = CmmMachOp (mkLtOp dflags mid_lit) [scrut, CmmLit (mkSimpleLit dflags mid_lit)] |