diff --git a/mlir/lib/Pass/Pass.cpp b/mlir/lib/Pass/Pass.cpp
--- a/mlir/lib/Pass/Pass.cpp
+++ b/mlir/lib/Pass/Pass.cpp
@@ -387,9 +387,28 @@
   // Invalidate any non preserved analyses.
   am.invalidate(pass->passState->preservedAnalyses);
 
+  // When verifyPasses is specified, we run the verifier (unless the pass
+  // failed).
+  //
+
   // Run the verifier if this pass didn't fail already.
-  if (!passFailed && verifyPasses)
-    passFailed = failed(verify(op));
+  if (!passFailed && verifyPasses) {
+    bool runVerifierNow = true;
+    // If the pass said that it preserved all analyses then it can't have
+    // permuted the IR, and we don't want to burn compile time running the
+    // verifier.  Similarly, if we just ran an OpToOpPassAdaptor (e.g. to run
+    // function passes within a module) then each subunit will have been
+    // verified on the subunit so there is little benefit in rerunning the
+    // verifier on the whole larger unit again.
+    //
+    // We run these checks in EXPENSIVE_CHECKS mode out of caution.
+#ifndef EXPENSIVE_CHECKS
+    runVerifierNow = !isa<OpToOpPassAdaptor>(pass) &&
+                     !pass->passState->preservedAnalyses.isAll();
+#endif
+    if (runVerifierNow)
+      passFailed = failed(verify(op));
+  }
 
   // Instrument after the pass has run.
   if (pi) {