diff --git a/mlir/lib/Conversion/SCFToSPIRV/SCFToSPIRV.cpp b/mlir/lib/Conversion/SCFToSPIRV/SCFToSPIRV.cpp
--- a/mlir/lib/Conversion/SCFToSPIRV/SCFToSPIRV.cpp
+++ b/mlir/lib/Conversion/SCFToSPIRV/SCFToSPIRV.cpp
@@ -17,6 +17,7 @@
 #include "mlir/Dialect/SPIRV/Transforms/SPIRVConversion.h"
 #include "mlir/IR/BuiltinOps.h"
 #include "mlir/Transforms/DialectConversion.h"
+#include "llvm/Support/FormatVariadic.h"
 
 using namespace mlir;
 
@@ -286,6 +287,10 @@
   SmallVector<Type, 8> returnTypes;
   for (auto result : ifOp.getResults()) {
     auto convertedType = typeConverter.convertType(result.getType());
+    if (!convertedType)
+      return rewriter.notifyMatchFailure(
+          loc, llvm::formatv("failed to convert type '{0}'", result.getType()));
+
     returnTypes.push_back(convertedType);
   }
   replaceSCFOutputValue(ifOp, selectionOp, rewriter, scfToSPIRVContext,
diff --git a/mlir/test/Conversion/SCFToSPIRV/if.mlir b/mlir/test/Conversion/SCFToSPIRV/if.mlir
--- a/mlir/test/Conversion/SCFToSPIRV/if.mlir
+++ b/mlir/test/Conversion/SCFToSPIRV/if.mlir
@@ -153,4 +153,18 @@
   return
 }
 
+// Memrefs without a spirv storage class are not supported. The conversion
+// should preserve the `scf.if` and not crash.
+func.func @unsupported_yield_type(%arg0 : memref<8xi32>, %arg1 : memref<8xi32>, %c : i1) {
+// CHECK-LABEL: @unsupported_yield_type
+// CHECK-NEXT:    scf.if
+// CHECK:         spirv.Return
+  %r = scf.if %c -> (memref<8xi32>) {
+    scf.yield %arg0 : memref<8xi32>
+  } else {
+    scf.yield %arg1 : memref<8xi32>
+  }
+  return
+}
+
 } // end module