[Transforms] Avoid repeated hash lookups (NFC)

[kazutakahirata]

No description provided.

[llvmbot]

@llvm/pr-subscribers-mlir-core

@llvm/pr-subscribers-mlir

Author: Kazu Hirata (kazutakahirata)

Changes

---

Full diff: https://github.com/llvm/llvm-project/pull/108139.diff

1 Files Affected:

• (modified) mlir/lib/Transforms/Utils/DialectConversion.cpp (+1-2)

diff --git a/mlir/lib/Transforms/Utils/DialectConversion.cpp b/mlir/lib/Transforms/Utils/DialectConversion.cpp
index 450e66f0db4e74..f288c7fc2cb77b 100644
--- a/mlir/lib/Transforms/Utils/DialectConversion.cpp
+++ b/mlir/lib/Transforms/Utils/DialectConversion.cpp
@@ -2486,9 +2486,8 @@ static void eraseDeadUnrealizedCasts(
 
     // Do not visit ops multiple times. If we find a circle, no live user was
     // found on the current path.
-    if (visited.contains(op))
+    if (!visited.insert(op).second)
       return false;
-    visited.insert(op);
 
     // Visit all users.
     for (Operation *user : op->getUsers()) {