From 5c716bdccce2fa504e1aa0b67226165d181d2459 Mon Sep 17 00:00:00 2001 From: Jakob Stoklund Olesen Date: Tue, 8 Feb 2011 18:50:21 +0000 Subject: Add SplitEditor::overlapIntv() to create small ranges where both registers are live. If a live range is used by a terminator instruction, and that live range needs to leave the block on the stack or in a different register, it can be necessary to have both sides of the split live at the terminator instruction. Example: %vreg2 = COPY %vreg1 JMP %vreg1 Becomes after spilling %vreg2: SPILL %vreg1 JMP %vreg1 The spill doesn't kill the register as is normally the case. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125102 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/SplitKit.cpp | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'lib/CodeGen/SplitKit.cpp') diff --git a/lib/CodeGen/SplitKit.cpp b/lib/CodeGen/SplitKit.cpp index 0c2a2cf432..e26d909211 100644 --- a/lib/CodeGen/SplitKit.cpp +++ b/lib/CodeGen/SplitKit.cpp @@ -882,6 +882,22 @@ SlotIndex SplitEditor::leaveIntvAtTop(MachineBasicBlock &MBB) { return VNI->def; } +void SplitEditor::overlapIntv(SlotIndex Start, SlotIndex End) { + assert(OpenIdx && "openIntv not called before overlapIntv"); + assert(Edit.getParent().getVNInfoAt(Start) == + Edit.getParent().getVNInfoAt(End.getPrevSlot()) && + "Parent changes value in extended range"); + assert(Edit.get(0)->getVNInfoAt(Start) && "Start must come from leaveIntv*"); + assert(LIS.getMBBFromIndex(Start) == LIS.getMBBFromIndex(End) && + "Range cannot span basic blocks"); + + // Treat this as useIntv() for now. The complement interval will be extended + // as needed by mapValue(). + DEBUG(dbgs() << " overlapIntv [" << Start << ';' << End << "):"); + RegAssign.insert(Start, End, OpenIdx); + DEBUG(dump()); +} + /// closeIntv - Indicate that we are done editing the currently open /// LiveInterval, and ranges can be trimmed. void SplitEditor::closeIntv() { -- cgit v1.2.3-70-g09d2