import Instruction
import Reg
-import Cmm
+import OldCmm
import Bag
import Digraph
import UniqFM
-- For Reg -> Reg moves, if the first reg dies at the same time the second reg is born
-- then the mov only serves to join live ranges. The two regs can be renamed to be
-- the same and the move instruction safely erased.
-
regCoalesce
:: Instruction instr
=> [LiveCmmTop instr]
-- | Slurp out mov instructions that only serve to join live ranges.
-- During a mov, if the source reg dies and the destiation reg is born
-- then we can rename the two regs to the same thing and eliminate the move.
---
slurpJoinMovs
:: Instruction instr
=> LiveCmmTop instr
slurpJoinMovs live
= slurpCmm emptyBag live
where
- slurpCmm rs CmmData{} = rs
- slurpCmm rs (CmmProc _ _ _ sccs) = foldl' slurpBlock rs (flattenSCCs sccs)
- slurpBlock rs (BasicBlock _ instrs) = foldl' slurpLI rs instrs
+ slurpCmm rs CmmData{} = rs
+ slurpCmm rs (CmmProc _ _ sccs) = foldl' slurpBlock rs (flattenSCCs sccs)
+ slurpBlock rs (BasicBlock _ instrs) = foldl' slurpLI rs instrs
- slurpLI rs (Instr _ Nothing) = rs
- slurpLI rs (Instr instr (Just live))
+ slurpLI rs (LiveInstr _ Nothing) = rs
+ slurpLI rs (LiveInstr instr (Just live))
| Just (r1, r2) <- takeRegRegMoveInstr instr
, elementOfUniqSet r1 $ liveDieRead live
, elementOfUniqSet r2 $ liveBorn live
| otherwise
= rs
-
- slurpLI rs SPILL{} = rs
- slurpLI rs RELOAD{} = rs