diff options
Diffstat (limited to 'compiler/cmm/CmmSwitch.hs')
| -rw-r--r-- | compiler/cmm/CmmSwitch.hs | 15 |
1 files changed, 13 insertions, 2 deletions
diff --git a/compiler/cmm/CmmSwitch.hs b/compiler/cmm/CmmSwitch.hs index 09abec6f8b..604e759208 100644 --- a/compiler/cmm/CmmSwitch.hs +++ b/compiler/cmm/CmmSwitch.hs @@ -258,12 +258,23 @@ targetSupportsSwitch _ = False -- | This function creates a SwitchPlan from a SwitchTargets value, breaking it -- down into smaller pieces suitable for code generation. createSwitchPlan :: SwitchTargets -> SwitchPlan -createSwitchPlan (SwitchTargets signed mbdef range m) = +-- Lets do the common case of a singleton map quicky and efficiently (#10677) +createSwitchPlan (SwitchTargets _signed _range (Just defLabel) m) + | [(x, l)] <- M.toList m + = IfEqual x l (Unconditionally defLabel) +-- And another common case, matching booleans +createSwitchPlan (SwitchTargets _signed (lo,hi) Nothing m) + | [(x1, l1), (x2,l2)] <- M.toAscList m + , x1 == lo + , x2 == hi + , x1 + 1 == x2 + = IfEqual x1 l1 (Unconditionally l2) +createSwitchPlan (SwitchTargets signed range mbdef m) = -- pprTrace "createSwitchPlan" (text (show ids) $$ text (show (range,m)) $$ text (show pieces) $$ text (show flatPlan) $$ text (show plan)) $ plan where pieces = concatMap breakTooSmall $ splitAtHoles maxJumpTableHole m - flatPlan = findSingleValues $ mkFlatSwitchPlan signed range mbdef pieces + flatPlan = findSingleValues $ mkFlatSwitchPlan signed mbdef range pieces plan = buildTree signed $ flatPlan |