Reuse unused val#'s to avoid running out of memory in extreme cases.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@70069 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/LiveInterval.cpp b/lib/CodeGen/LiveInterval.cpp
index 39d6611..0450c35 100644
--- a/lib/CodeGen/LiveInterval.cpp
+++ b/lib/CodeGen/LiveInterval.cpp
@@ -577,6 +577,7 @@
if (Clobbers.empty()) return;
DenseMap<VNInfo*, VNInfo*> ValNoMaps;
+ VNInfo *UnusedValNo = 0;
iterator IP = begin();
for (const_iterator I = Clobbers.begin(), E = Clobbers.end(); I != E; ++I) {
// For every val# in the Clobbers interval, create a new "unknown" val#.
@@ -584,8 +585,10 @@
DenseMap<VNInfo*, VNInfo*>::iterator VI = ValNoMaps.find(I->valno);
if (VI != ValNoMaps.end())
ClobberValNo = VI->second;
+ else if (UnusedValNo)
+ ClobberValNo = UnusedValNo;
else {
- ClobberValNo = getNextValue(~0U, 0, VNInfoAllocator);
+ UnusedValNo = ClobberValNo = getNextValue(~0U, 0, VNInfoAllocator);
ValNoMaps.insert(std::make_pair(I->valno, ClobberValNo));
}
@@ -623,6 +626,7 @@
// Insert the clobber interval.
IP = addRangeFrom(LiveRange(SubRangeStart, SubRangeEnd, ClobberValNo),
IP);
+ UnusedValNo = 0;
}
}
}