[llvm] [Support] Simplify yamlizeMappingEnumInput (NFC) (PR #137537)

[Kazu Hirata via llvm-commits]

https://github.com/kazutakahirata created https://github.com/llvm/llvm-project/pull/137537

We can use "constexpt if" to combine the two variants of functions.


>From c6bd40dd02be0c7aaf19f3512725d3403b1b1d58 Mon Sep 17 00:00:00 2001
From: Kazu Hirata <kazu at google.com>
Date: Sun, 27 Apr 2025 10:45:02 -0700
Subject: [PATCH] [Support] Simplify yamlizeMappingEnumInput (NFC)

We can use "constexpt if" to combine the two variants of functions.
---
 llvm/include/llvm/Support/YAMLTraits.h | 26 +++++++++++---------------
 1 file changed, 11 insertions(+), 15 deletions(-)

diff --git a/llvm/include/llvm/Support/YAMLTraits.h b/llvm/include/llvm/Support/YAMLTraits.h
index e707a445012b5..21829b906967e 100644
--- a/llvm/include/llvm/Support/YAMLTraits.h
+++ b/llvm/include/llvm/Support/YAMLTraits.h
@@ -1105,22 +1105,18 @@ yamlize(IO &io, T &Val, bool, Context &Ctx) {
 }
 
 template <typename T, typename Context>
-std::enable_if_t<!has_MappingEnumInputTraits<T, Context>::value, bool>
-yamlizeMappingEnumInput(IO &io, T &Val) {
-  return false;
-}
-
-template <typename T, typename Context>
-std::enable_if_t<has_MappingEnumInputTraits<T, Context>::value, bool>
-yamlizeMappingEnumInput(IO &io, T &Val) {
-  if (io.outputting())
-    return false;
+bool yamlizeMappingEnumInput(IO &io, T &Val) {
+  if constexpr (has_MappingEnumInputTraits<T, Context>::value) {
+    if (io.outputting())
+      return false;
 
-  io.beginEnumScalar();
-  MappingTraits<T>::enumInput(io, Val);
-  bool Matched = !io.matchEnumFallback();
-  io.endEnumScalar();
-  return Matched;
+    io.beginEnumScalar();
+    MappingTraits<T>::enumInput(io, Val);
+    bool Matched = !io.matchEnumFallback();
+    io.endEnumScalar();
+    return Matched;
+  }
+  return false;
 }
 
 template <typename T, typename Context>