Preserve the register coallescer, and update live intervals more correctly by trigger...

[oota-llvm.git] / lib / CodeGen / SimpleRegisterCoalescing.h

diff --git a/lib/CodeGen/SimpleRegisterCoalescing.h b/lib/CodeGen/SimpleRegisterCoalescing.h
index 7823ba0df4b2110499b93c08587f91f61e37834d..5b3d6b67a91b8291f3adb9eddaeadf30c3e009f4 100644 (file)
--- a/lib/CodeGen/SimpleRegisterCoalescing.h
+++ b/lib/CodeGen/SimpleRegisterCoalescing.h
@@ -223,6 +223,8 @@ namespace llvm {
     /// subregister.
     void UpdateRegDefsUses(unsigned SrcReg, unsigned DstReg, unsigned SubIdx);
 
+    /// RemoveDeadImpDef - Remove implicit_def instructions which are
+    /// "re-defining" registers due to insert_subreg coalescing. e.g.
     void RemoveDeadImpDef(unsigned Reg, LiveInterval &LI);
 
     /// RemoveUnnecessaryKills - Remove kill markers that are no longer accurate
@@ -230,14 +232,14 @@ namespace llvm {
     void RemoveUnnecessaryKills(unsigned Reg, LiveInterval &LI);
 
     /// ShortenDeadCopyLiveRange - Shorten a live range defined by a dead copy.
-    ///
-    void ShortenDeadCopyLiveRange(LiveInterval &li, MachineInstr *CopyMI);
+    /// Return true if live interval is removed.
+    bool ShortenDeadCopyLiveRange(LiveInterval &li, MachineInstr *CopyMI);
 
     /// ShortenDeadCopyLiveRange - Shorten a live range as it's artificially
     /// extended by a dead copy. Mark the last use (if any) of the val# as kill
     /// as ends the live range there. If there isn't another use, then this
-    /// live range is dead.
-    void ShortenDeadCopySrcLiveRange(LiveInterval &li, MachineInstr *CopyMI);
+    /// live range is dead. Return true if live interval is removed.
+    bool ShortenDeadCopySrcLiveRange(LiveInterval &li, MachineInstr *CopyMI);
 
     /// lastRegisterUse - Returns the last use of the specific register between
     /// cycles Start and End or NULL if there are no uses.