Fix PR6520. An earlyclobber physreg must not be allocated to anything else.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103133 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/RegAllocLocal.cpp b/lib/CodeGen/RegAllocLocal.cpp
index 94456d1..a3d2f9d 100644
--- a/lib/CodeGen/RegAllocLocal.cpp
+++ b/lib/CodeGen/RegAllocLocal.cpp
@@ -843,8 +843,18 @@
SmallVector<unsigned, 8> Kills;
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
MachineOperand &MO = MI->getOperand(i);
- if (!MO.isReg() || !MO.isKill()) continue;
-
+ if (!MO.isReg()) continue;
+ unsigned Reg = MO.getReg();
+ if (!Reg) continue;
+
+ // Avoid allocating assigned early clobbers below.
+ if (MO.isEarlyClobber() && TargetRegisterInfo::isPhysicalRegister(Reg)) {
+ spillPhysReg(MBB, MI, Reg, true); // Spill any existing value in reg
+ PhysRegsUsed[Reg] = 0; // It is free and reserved now
+ AddToPhysRegsUseOrder(Reg);
+ }
+
+ if (!MO.isKill()) continue;
if (!MO.isImplicit())
Kills.push_back(MO.getReg());
else if (!isReadModWriteImplicitKill(MI, MO.getReg()))