1 files changed, 6 insertions, 0 deletions
diff --git a/llvm/lib/CodeGen/StackMaps.cpp b/llvm/lib/CodeGen/StackMaps.cpp
index 220e85f..faf07e9 100644
--- a/llvm/lib/CodeGen/StackMaps.cpp
+++ b/llvm/lib/CodeGen/StackMaps.cpp
@@ -234,6 +234,12 @@ StackMaps::parseOperand(MachineInstr::const_mop_iterator MOI,
     if (MOI->isImplicit())
       return ++MOI;
 
+    if (MOI->isUndef()) {
+      // Record `undef` register as constant. Use same value as ISel uses.
+      Locs.emplace_back(Location::Constant, sizeof(int64_t), 0, 0xFEFEFEFE);
+      return ++MOI;
+    }
+
     assert(Register::isPhysicalRegister(MOI->getReg()) &&
            "Virtreg operands should have been rewritten before now.");
     const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(MOI->getReg());