improve "cannot yet select" errors a trivial amount: now

[oota-llvm.git] / lib / CodeGen / LiveIntervalUnion.cpp

diff --git a/lib/CodeGen/LiveIntervalUnion.cpp b/lib/CodeGen/LiveIntervalUnion.cpp
index 079468a4f0398971d642fc7e0f3795337873359e..cec68850fa884da856d789939e93bedb098d73c9 100644 (file)
--- 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"
@@ -237,7 +238,7 @@ collectInterferingVRegs(unsigned MaxInterferingRegs) {
   InterferenceResult IR = firstInterference();
   LiveInterval::iterator VirtRegEnd = VirtReg->end();
   LiveInterval *RecentInterferingVReg = NULL;
-  while (IR.LiveUnionI.valid()) {
+  if (IR.VirtRegI != VirtRegEnd) while (IR.LiveUnionI.valid()) {
     // Advance the union's iterator to reach an unseen interfering vreg.
     do {
       if (IR.LiveUnionI.value() == RecentInterferingVReg)
@@ -284,3 +285,30 @@ collectInterferingVRegs(unsigned MaxInterferingRegs) {
   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());
+  }
+}