Checkpoint SplitKit progress.
We are now at a point where we can split around simple single-entry, single-exit
loops, although still with some bugs.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@110257 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SplitKit.h b/lib/CodeGen/SplitKit.h
index 601fc17..6ded4f4 100644
--- a/lib/CodeGen/SplitKit.h
+++ b/lib/CodeGen/SplitKit.h
@@ -121,14 +121,14 @@
/// SplitEditor - Edit machine code and LiveIntervals for live range
/// splitting.
///
-/// 1. Create a SplitEditor from a SplitAnalysis. This will create a new
-/// LiveInterval, dupli, that is identical to SA.curli.
-/// 2. Start a new live interval with openLI.
-/// 3. Insert copies to the new interval with copyTo* and mark the ranges where
-/// it should be used with use*.
-/// 4. Insert back-copies with copyFromLI.
-/// 5. Finish the current LI with closeLI and repeat from 2.
-/// 6. Rewrite instructions with rewrite().
+/// - Create a SplitEditor from a SplitAnalysis. This will create a new
+/// LiveInterval, dupli, that is identical to SA.curli.
+/// - Start a new live interval with openIntv.
+/// - Mark the places where the new interval is entered using enterIntv*
+/// - Mark the ranges where the new interval is used with useIntv*
+/// - Mark the places where the interval is exited with exitIntv*.
+/// - Finish the current interval with closeIntv and repeat from 2.
+/// - Rewrite instructions with rewrite().
///
class SplitEditor {
SplitAnalysis &sa_;
@@ -138,7 +138,7 @@
const TargetInstrInfo &tii_;
/// dupli_ - Created as a copy of sa_.curli_, ranges are carved out as new
- /// intervals get added through openLI / closeLI.
+ /// intervals get added through openIntv / closeIntv.
LiveInterval *dupli_;
/// Currently open LiveInterval.
@@ -148,43 +148,60 @@
/// register class and spill slot as curli.
LiveInterval *createInterval();
- /// valueMap_ - Map values in dupli to values in openli. These are direct 1-1
+ /// valueMap_ - Map values in dupli to values in openIntv. These are direct 1-1
/// mappings, and do not include values created by inserted copies.
DenseMap<VNInfo*,VNInfo*> valueMap_;
- /// mapValue - Return the openli value that corresponds to the given dupli
+ /// mapValue - Return the openIntv value that corresponds to the given dupli
/// value.
- VNInfo *mapValue(VNInfo *dupliVNI);
+ VNInfo *mapValue(VNInfo *dupliVNI);
+
+ /// A dupli value is live through openIntv.
+ bool liveThrough_;
+
+ /// All the new intervals created for this split are added to intervals_.
+ std::vector<LiveInterval*> &intervals_;
+
+ /// The index into intervals_ of the first interval we added. There may be
+ /// others from before we got it.
+ unsigned firstInterval;
+
+ /// Insert a COPY instruction curli -> li. Allocate a new value from li
+ /// defined by the COPY
+ VNInfo *insertCopy(LiveInterval &LI,
+ MachineBasicBlock &MBB,
+ MachineBasicBlock::iterator I);
public:
/// Create a new SplitEditor for editing the LiveInterval analyzed by SA.
- SplitEditor(SplitAnalysis&, LiveIntervals&, VirtRegMap&);
+ /// Newly created intervals will be appended to newIntervals.
+ SplitEditor(SplitAnalysis &SA, LiveIntervals&, VirtRegMap&,
+ std::vector<LiveInterval*> &newIntervals);
/// getAnalysis - Get the corresponding analysis.
SplitAnalysis &getAnalysis() { return sa_; }
- /// Create a new virtual register and live interval to be used by following
- /// use* and copy* calls.
- void openLI();
+ /// Create a new virtual register and live interval.
+ void openIntv();
- /// copyToPHI - Insert a copy to openli at the end of A, and catch it with a
- /// PHI def at the beginning of the successor B. This call is ignored if dupli
- /// is not live out of A.
- void copyToPHI(MachineBasicBlock &A, MachineBasicBlock &B);
+ /// enterIntvAtEnd - Enter openli at the end of MBB.
+ /// PhiMBB is a successor inside openli where a PHI value is created.
+ /// Currently, all entries must share the same PhiMBB.
+ void enterIntvAtEnd(MachineBasicBlock &MBB, MachineBasicBlock &PhiMBB);
- /// useLI - indicate that all instructions in MBB should use openli.
- void useLI(const MachineBasicBlock &MBB);
+ /// useIntv - indicate that all instructions in MBB should use openli.
+ void useIntv(const MachineBasicBlock &MBB);
- /// useLI - indicate that all instructions in range should use openli.
- void useLI(SlotIndex Start, SlotIndex End);
+ /// useIntv - indicate that all instructions in range should use openli.
+ void useIntv(SlotIndex Start, SlotIndex End);
- /// copyFromLI - Insert a copy back to dupli from openli at position I.
- /// This also marks the remainder of MBB as not used by openli.
- SlotIndex copyFromLI(MachineBasicBlock &MBB, MachineBasicBlock::iterator I);
+ /// leaveIntvAtTop - Leave the interval at the top of MBB.
+ /// Currently, only one value can leave the interval.
+ void leaveIntvAtTop(MachineBasicBlock &MBB);
- /// closeLI - Indicate that we are done editing the currently open
+ /// closeIntv - Indicate that we are done editing the currently open
/// LiveInterval, and ranges can be trimmed.
- void closeLI();
+ void closeIntv();
/// rewrite - after all the new live ranges have been created, rewrite
/// instructions using curli to use the new intervals.