[llvm] [Support] Simplify setDefaultImpl (NFC) (PR #137528)

[Kazu Hirata via llvm-commits]

https://github.com/kazutakahirata updated https://github.com/llvm/llvm-project/pull/137528

>From ea2d0bec1f8a2ea05e22b3227d6e28672a24d966 Mon Sep 17 00:00:00 2001
From: Kazu Hirata <kazu at google.com>
Date: Sun, 27 Apr 2025 09:08:44 -0700
Subject: [PATCH 1/2] [Support] Simplify setDefaultImpl (NFC)

We can use "constexpr if" to combine the two variants of functions.
---
 llvm/include/llvm/Support/CommandLine.h | 18 ++++++++----------
 1 file changed, 8 insertions(+), 10 deletions(-)

diff --git a/llvm/include/llvm/Support/CommandLine.h b/llvm/include/llvm/Support/CommandLine.h
index 5d60bb64bbb20..4c9f5bae87759 100644
--- a/llvm/include/llvm/Support/CommandLine.h
+++ b/llvm/include/llvm/Support/CommandLine.h
@@ -1459,18 +1459,16 @@ class opt
     }
   }
 
-  template <class T, class = std::enable_if_t<std::is_assignable_v<T &, T>>>
-  void setDefaultImpl() {
-    const OptionValue<DataType> &V = this->getDefault();
-    if (V.hasValue())
-      this->setValue(V.getValue());
-    else
-      this->setValue(T());
+  template <class T> void setDefaultImpl() {
+    if constexpr (std::is_assignable_v<T &, T>) {
+      const OptionValue<DataType> &V = this->getDefault();
+      if (V.hasValue())
+        this->setValue(V.getValue());
+      else
+        this->setValue(T());
+    }
   }
 
-  template <class T, class = std::enable_if_t<!std::is_assignable_v<T &, T>>>
-  void setDefaultImpl(...) {}
-
   void setDefault() override { setDefaultImpl<DataType>(); }
 
   void done() {

>From 3d437a2530821d2fc79573faf2e2453469304f62 Mon Sep 17 00:00:00 2001
From: Kazu Hirata <kazu at google.com>
Date: Sun, 27 Apr 2025 12:47:22 -0700
Subject: [PATCH 2/2] Address a comment.

---
 llvm/include/llvm/Support/CommandLine.h | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/llvm/include/llvm/Support/CommandLine.h b/llvm/include/llvm/Support/CommandLine.h
index 4c9f5bae87759..531750572102c 100644
--- a/llvm/include/llvm/Support/CommandLine.h
+++ b/llvm/include/llvm/Support/CommandLine.h
@@ -1459,18 +1459,16 @@ class opt
     }
   }
 
-  template <class T> void setDefaultImpl() {
-    if constexpr (std::is_assignable_v<T &, T>) {
+  void setDefault() override {
+    if constexpr (std::is_assignable_v<DataType &, DataType>) {
       const OptionValue<DataType> &V = this->getDefault();
       if (V.hasValue())
         this->setValue(V.getValue());
       else
-        this->setValue(T());
+        this->setValue(DataType());
     }
   }
 
-  void setDefault() override { setDefaultImpl<DataType>(); }
-
   void done() {
     addArgument();
     Parser.initialize();