Provide LiveIntervalUnion::Query::checkLoopInterference.
This is a three-way interval list intersection between a virtual register, a
live interval union, and a loop. It will be used to identify interference-free
loops for live range splitting.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122034 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/LiveIntervalUnion.cpp b/lib/CodeGen/LiveIntervalUnion.cpp
index 079468a..7ebe96f 100644
--- a/lib/CodeGen/LiveIntervalUnion.cpp
+++ b/lib/CodeGen/LiveIntervalUnion.cpp
@@ -16,6 +16,7 @@
#define DEBUG_TYPE "regalloc"
#include "LiveIntervalUnion.h"
#include "llvm/ADT/SparseBitVector.h"
+#include "llvm/CodeGen/MachineLoopRanges.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetRegisterInfo.h"
@@ -284,3 +285,30 @@
SeenAllInterferences = true;
return InterferingVRegs.size();
}
+
+bool LiveIntervalUnion::Query::checkLoopInterference(MachineLoopRange *Loop) {
+ // VirtReg is likely live throughout the loop, so start by checking LIU-Loop
+ // overlaps.
+ IntervalMapOverlaps<LiveIntervalUnion::Map, MachineLoopRange::Map>
+ Overlaps(LiveUnion->getMap(), Loop->getMap());
+ if (!Overlaps.valid())
+ return false;
+
+ // The loop is overlapping an LIU assignment. Check VirtReg as well.
+ LiveInterval::iterator VRI = VirtReg->find(Overlaps.start());
+
+ for (;;) {
+ if (VRI == VirtReg->end())
+ return false;
+ if (VRI->start < Overlaps.stop())
+ return true;
+
+ Overlaps.advanceTo(VRI->start);
+ if (!Overlaps.valid())
+ return false;
+ if (Overlaps.start() < VRI->end)
+ return true;
+
+ VRI = VirtReg->advanceTo(VRI, Overlaps.start());
+ }
+}