Revert "[IR] Simplify HasCachedHash with is_detected (NFC) (#159510)" (#159622)
This reverts commit d6b7ac830ab4c1b26a1b2eecd15306eccf9cea90. Build
breakages reported on the PR hint at not working with certain versions
of the host compiler.
diff --git a/llvm/lib/IR/Metadata.cpp b/llvm/lib/IR/Metadata.cpp
index 09e25ce..fc78a5b 100644
--- a/llvm/lib/IR/Metadata.cpp
+++ b/llvm/lib/IR/Metadata.cpp
@@ -986,10 +986,15 @@
}
template <class NodeTy> struct MDNode::HasCachedHash {
- template <class U>
- using check = decltype(static_cast<void (U::*)(unsigned)>(&U::setHash));
+ using Yes = char[1];
+ using No = char[2];
+ template <class U, U Val> struct SFINAE {};
- static constexpr bool value = is_detected<check, NodeTy>::value;
+ template <class U>
+ static Yes &check(SFINAE<void (U::*)(unsigned), &U::setHash> *);
+ template <class U> static No &check(...);
+
+ static const bool value = sizeof(check<NodeTy>(nullptr)) == sizeof(Yes);
};
MDNode *MDNode::uniquify() {
