1 files changed, 19 insertions, 0 deletions

diff --git a/contrib/llvm-project/llvm/lib/CodeGen/SwiftErrorValueTracking.cpp b/contrib/llvm-project/llvm/lib/CodeGen/SwiftErrorValueTracking.cpp
index 83a7063de112..74a94d6110f4 100644
--- a/contrib/llvm-project/llvm/lib/CodeGen/SwiftErrorValueTracking.cpp
+++ b/contrib/llvm-project/llvm/lib/CodeGen/SwiftErrorValueTracking.cpp
@@ -253,6 +253,25 @@ void SwiftErrorValueTracking::propagateVRegs() {
         setCurrentVReg(MBB, SwiftErrorVal, PHIVReg);
     }
   }
+
+  // Create implicit defs for upward uses from unreachable blocks
+  MachineRegisterInfo &MRI = MF->getRegInfo();
+  for (const auto &Use : VRegUpwardsUse) {
+    const MachineBasicBlock *UseBB = Use.first.first;
+    Register VReg = Use.second;
+    if (!MRI.def_begin(VReg).atEnd())
+      continue;
+
+#ifdef EXPENSIVE_CHECKS
+    assert(std::find(RPOT.begin(), RPOT.end(), UseBB) == RPOT.end() &&
+           "Reachable block has VReg upward use without definition.");
+#endif
+
+    MachineBasicBlock *UseBBMut = MF->getBlockNumbered(UseBB->getNumber());
+
+    BuildMI(*UseBBMut, UseBBMut->getFirstNonPHI(), DebugLoc(),
+            TII->get(TargetOpcode::IMPLICIT_DEF), VReg);
+  }
 }
 
 void SwiftErrorValueTracking::preassignVRegs(