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
diff --git a/lib/CodeGen/SplitKit.cpp b/lib/CodeGen/SplitKit.cpp
index 0c2a2cf..e26d909 100644
--- a/lib/CodeGen/SplitKit.cpp
+++ b/lib/CodeGen/SplitKit.cpp
@@ -882,6 +882,22 @@
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() {