From 13a7aadf73f97d953897d6b94157412ff130d3c2 Mon Sep 17 00:00:00 2001
From: River Riddle <riddleriver@gmail.com>
Date: Thu, 15 Apr 2021 16:09:08 -0700
Subject: [PATCH] [mlir] Add support for walking locations similarly to
 Operations

This allows for walking all nested locations of a given location, and is generally useful when processing locations.

Differential Revision: https://reviews.llvm.org/D100437
---
 include/llvm/ADT/TypeSwitch.h    | 6 ++++++
 unittests/ADT/TypeSwitchTest.cpp | 2 +-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/include/llvm/ADT/TypeSwitch.h b/include/llvm/ADT/TypeSwitch.h
index bfcb2064301..815b9a40afa 100644
--- a/include/llvm/ADT/TypeSwitch.h
+++ b/include/llvm/ADT/TypeSwitch.h
@@ -124,6 +124,12 @@ public:
       return std::move(*result);
     return defaultFn(this->value);
   }
+  /// As a default, return the given value.
+  LLVM_NODISCARD ResultT Default(ResultT defaultResult) {
+    if (result)
+      return std::move(*result);
+    return defaultResult;
+  }
 
   LLVM_NODISCARD
   operator ResultT() {
diff --git a/unittests/ADT/TypeSwitchTest.cpp b/unittests/ADT/TypeSwitchTest.cpp
index fde423d011b..442ac1910a0 100644
--- a/unittests/ADT/TypeSwitchTest.cpp
+++ b/unittests/ADT/TypeSwitchTest.cpp
@@ -47,7 +47,7 @@ TEST(TypeSwitchTest, CasesResult) {
     return TypeSwitch<Base *, int>(&value)
         .Case<DerivedA, DerivedB, DerivedD>([](auto *) { return 0; })
         .Case([](DerivedC *) { return 1; })
-        .Default([](Base *) { return -1; });
+        .Default(-1);
   };
   EXPECT_EQ(0, translate(DerivedA()));
   EXPECT_EQ(0, translate(DerivedB()));