diff --git a/mlir/lib/IR/AsmPrinter.cpp b/mlir/lib/IR/AsmPrinter.cpp
--- a/mlir/lib/IR/AsmPrinter.cpp
+++ b/mlir/lib/IR/AsmPrinter.cpp
@@ -38,6 +38,7 @@
 #include "llvm/ADT/StringSet.h"
 #include "llvm/ADT/TypeSwitch.h"
 #include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Debug.h"
 #include "llvm/Support/Endian.h"
 #include "llvm/Support/Regex.h"
 #include "llvm/Support/SaveAndRestore.h"
@@ -48,6 +49,8 @@
 using namespace mlir;
 using namespace mlir::detail;
 
+#define DEBUG_TYPE "asm-printer"
+
 void OperationName::print(raw_ostream &os) const { os << getStringRef(); }
 
 void OperationName::dump() const { print(llvm::errs()); }
@@ -1313,14 +1316,26 @@
       printerFlags.shouldAssumeVerified())
     return printerFlags;
 
+  LLVM_DEBUG(llvm::dbgs() << "Verify op before printing: "
+                          << op->getName().getStringRef() << "\n");
+
   // Ignore errors emitted by the verifier. We check the thread id to avoid
   // consuming other threads' errors.
   auto parentThreadId = llvm::get_threadid();
-  ScopedDiagnosticHandler diagHandler(op->getContext(), [&](Diagnostic &) {
-    return success(parentThreadId == llvm::get_threadid());
+  ScopedDiagnosticHandler diagHandler(op->getContext(), [&](Diagnostic &diag) {
+    if (parentThreadId == llvm::get_threadid()) {
+      LLVM_DEBUG(llvm::dbgs() << "op-printing verification:\n"
+                              << diag.str() << "\n");
+      return success();
+    }
+    return failure();
   });
-  if (failed(verify(op)))
+  if (failed(verify(op))) {
+    LLVM_DEBUG(llvm::dbgs()
+               << op->getName().getStringRef()
+               << " failed on verification, will be printed in generic form\n");
     printerFlags.printGenericOpForm();
+  }
 
   return printerFlags;
 }