diff --git a/src/compiler/cgir/pass/cg_split_kit.cpp b/src/compiler/cgir/pass/cg_split_kit.cpp
index 045b683e..2a173813 100644
--- a/src/compiler/cgir/pass/cg_split_kit.cpp
+++ b/src/compiler/cgir/pass/cg_split_kit.cpp
@@ -693,7 +693,32 @@ CgSlotIndex CgSplitEditor::enterIntvAfter(CgSlotIndex Idx) {
   }
   LLVM_DEBUG(dbgs() << ": valno " << ParentVNI->id << '\n');
   CgInstruction *MI = LIS.getInstructionFromIndex(Idx);
-  assert(MI && "enterIntvAfter called with invalid index");
+  if (!MI) {
+    LLVM_DEBUG(dbgs() << "      no MI at " << Idx << ", resolving via MBB\n");
+    CgBasicBlock *MBB = LIS.getMBBFromIndex(Idx);
+    if (!MBB) {
+      LLVM_DEBUG(dbgs() << "      no MBB for index, keeping " << Idx << '\n');
+      return Idx;
+    }
+
+    CgSlotIndex End = LIS.getMBBEndIdx(MBB);
+    if (Idx >= End.getPrevSlot()) {
+      LLVM_DEBUG(dbgs() << "      at end of " << printCgBBReference(*MBB)
+                        << ", using end\n");
+      return enterIntvAtEnd(*MBB);
+    }
+
+    CgSlotIndex NextIdx = LIS.getSlotIndexes()->getNextNonNullIndex(Idx);
+    CgInstruction *NextMI = LIS.getInstructionFromIndex(NextIdx);
+    if (!NextMI || NextMI->getParent() != MBB) {
+      LLVM_DEBUG(dbgs() << "      next MI not in block, using end\n");
+      return enterIntvAtEnd(*MBB);
+    }
+
+    CgVNInfo *VNI =
+        defFromParent(OpenIdx, ParentVNI, Idx, *MBB, NextMI->getIterator());
+    return VNI->def;
+  }
 
   CgVNInfo *VNI = defFromParent(OpenIdx, ParentVNI, Idx, *MI->getParent(),
                                 std::next(CgBasicBlock::iterator(MI)));