1 files changed, 16 insertions, 6 deletions
diff --git a/llvm/utils/TableGen/GlobalISelEmitter.cpp b/llvm/utils/TableGen/GlobalISelEmitter.cpp
index 2e52c8e6fc9..8079e2989b6 100644
--- a/llvm/utils/TableGen/GlobalISelEmitter.cpp
+++ b/llvm/utils/TableGen/GlobalISelEmitter.cpp
@@ -881,12 +881,19 @@ public:
 
   void defineOperand(StringRef SymbolicName, OperandMatcher &OM);
 
-  void defineComplexSubOperand(StringRef SymbolicName, Record *ComplexPattern,
-                               unsigned RendererID, unsigned SubOperandID) {
-    assert(ComplexSubOperands.count(SymbolicName) == 0 && "Already defined");
+  Error defineComplexSubOperand(StringRef SymbolicName, Record *ComplexPattern,
+                                unsigned RendererID, unsigned SubOperandID) {
+    if (ComplexSubOperands.count(SymbolicName))
+      return failedImport(
+          "Complex suboperand referenced more than once (Operand: " +
+          SymbolicName + ")");
+
     ComplexSubOperands[SymbolicName] =
         std::make_tuple(ComplexPattern, RendererID, SubOperandID);
+
+    return Error::success();
   }
+
   Optional<DefinedComplexPatternSubOperand>
   getComplexSubOperand(StringRef SymbolicName) const {
     const auto &I = ComplexSubOperands.find(SymbolicName);
@@ -3421,9 +3428,12 @@ Error GlobalISelEmitter::importChildMatcher(RuleMatcher &Rule,
 
       for (unsigned i = 0, e = SrcChild->getNumChildren(); i != e; ++i) {
         auto *SubOperand = SrcChild->getChild(i);
-        if (!SubOperand->getName().empty())
-          Rule.defineComplexSubOperand(SubOperand->getName(),
-                                       SrcChild->getOperator(), RendererID, i);
+        if (!SubOperand->getName().empty()) {
+          if (auto Error = Rule.defineComplexSubOperand(SubOperand->getName(),
+                                                        SrcChild->getOperator(),
+                                                        RendererID, i))
+            return Error;
+        }
       }
 
       return Error::success();