Avoid comparing invalid slot indexes, and assert that it doesn't happen.
The SlotIndex created by the default construction does not represent a position
in the function, and it doesn't make sense to compare it to other indexes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126924 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/RegAllocLinearScan.cpp b/lib/CodeGen/RegAllocLinearScan.cpp
index b959878..a24fc80 100644
--- a/lib/CodeGen/RegAllocLinearScan.cpp
+++ b/lib/CodeGen/RegAllocLinearScan.cpp
@@ -458,7 +458,7 @@
const LiveRange &range = cur.ranges.front();
VNInfo *vni = range.valno;
- if (vni->isUnused())
+ if (vni->isUnused() || !vni->def.isValid())
return Reg;
unsigned CandReg;
@@ -993,7 +993,7 @@
// one, e.g. X86::mov32to32_. These move instructions are not coalescable.
if (!vrm_->getRegAllocPref(cur->reg) && cur->hasAtLeastOneValue()) {
VNInfo *vni = cur->begin()->valno;
- if (!vni->isUnused()) {
+ if (!vni->isUnused() && vni->def.isValid()) {
MachineInstr *CopyMI = li_->getInstructionFromIndex(vni->def);
if (CopyMI && CopyMI->isCopy()) {
unsigned DstSubReg = CopyMI->getOperand(0).getSubReg();