Teach ConnectedVNInfoEqClasses::Classify to deal with unused values.
We don't want unused values forming their own equivalence classes, so we lump
them all together in one class, and then merge them with the class of the last
used value.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117670 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/LiveInterval.cpp b/lib/CodeGen/LiveInterval.cpp
index 27a572c..3c18017 100644
--- a/lib/CodeGen/LiveInterval.cpp
+++ b/lib/CodeGen/LiveInterval.cpp
@@ -740,11 +740,20 @@
for (unsigned i = 0, e = LI->getNumValNums(); i != e; ++i)
eqClass_.push_back(i);
+ const VNInfo *used = 0, *unused = 0;
+
// Determine connections.
for (LiveInterval::const_vni_iterator I = LI->vni_begin(), E = LI->vni_end();
I != E; ++I) {
const VNInfo *VNI = *I;
- assert(!VNI->isUnused() && "Cannot handle unused values");
+ // Group all unused values into one class.
+ if (VNI->isUnused()) {
+ if (unused)
+ Connect(unused->id, VNI->id);
+ unused = VNI;
+ continue;
+ }
+ used = VNI;
if (VNI->isPHIDef()) {
const MachineBasicBlock *MBB = lis_.getMBBFromIndex(VNI->def);
assert(MBB && "Phi-def has no defining MBB");
@@ -762,6 +771,11 @@
Connect(VNI->id, UVNI->id);
}
}
+
+ // Lump all the unused values in with the last used value.
+ if (used && unused)
+ Connect(used->id, unused->id);
+
return Renumber();
}