Index: mlir/lib/Conversion/UBToLLVM/UBToLLVM.cpp
===================================================================
--- mlir/lib/Conversion/UBToLLVM/UBToLLVM.cpp
+++ mlir/lib/Conversion/UBToLLVM/UBToLLVM.cpp
@@ -42,15 +42,16 @@
 LogicalResult
 PoisonOpLowering::matchAndRewrite(ub::PoisonOp op, OpAdaptor adaptor,
                                   ConversionPatternRewriter &rewriter) const {
-  Type origType = op.getType();
-  if (!origType.isIntOrIndexOrFloat())
-    return rewriter.notifyMatchFailure(
-        op, [&](Diagnostic &diag) { diag << "unsupported type " << origType; });
+  if (!isa<ub::PoisonAttr>(op.getValue()))
+    return rewriter.notifyMatchFailure(op, [&](Diagnostic &diag) {
+      diag << "pattern can only convert op with '"
+           << ub::PoisonAttr::getMnemonic() << "' poison value";
+    });
 
-  Type resType = getTypeConverter()->convertType(origType);
+  Type resType = getTypeConverter()->convertType(op.getType());
   if (!resType)
     return rewriter.notifyMatchFailure(op, [&](Diagnostic &diag) {
-      diag << "failed to convert result type " << origType;
+      diag << "failed to convert result type " << op.getType();
     });
 
   rewriter.replaceOpWithNewOp<LLVM::PoisonOp>(op, resType);
Index: mlir/test/Conversion/UBToLLVM/ub-to-llvm.mlir
===================================================================
--- mlir/test/Conversion/UBToLLVM/ub-to-llvm.mlir
+++ mlir/test/Conversion/UBToLLVM/ub-to-llvm.mlir
@@ -12,5 +12,7 @@
   %1 = ub.poison : i16
 // CHECK: {{.*}} = llvm.mlir.poison : f64
   %2 = ub.poison : f64
+// CHECK: {{.*}} = llvm.mlir.poison : !llvm.ptr
+  %3 = ub.poison : !llvm.ptr
   return
 }