[llvm][GenericUniformity] Hack around strict is_invocable() checks

With recent (> 15, as far as I can tell, possibly > 16) clang, c++17,
and GNU's libstdc++ (versions 9 and 10 and maybe others), LLVM fails
to compile due to an is_invocable() check in unique_ptr::reset().

To resolve this issue, add a template argument to ImplDeleter to make
things work.

Differential Revision: https://reviews.llvm.org/D141865

Author: krzysz00

llvm/include/llvm/ADT/GenericUniformityImpl.h

@@ -467,9 +467,8 @@ template <typename ContextT> class GenericUniformityAnalysisImpl {
                            ConstValueRefT Val) const;
 };
 
-template <typename ContextT>
-void GenericUniformityInfo<ContextT>::ImplDeleter::operator()(
-    GenericUniformityAnalysisImpl<ContextT> *Impl) {
+template <typename ImplT>
+void GenericUniformityAnalysisImplDeleter<ImplT>::operator()(ImplT *Impl) {
   delete Impl;
 }
 

llvm/include/llvm/ADT/GenericUniformityInfo.h

@@ -24,6 +24,14 @@ namespace llvm {
 class TargetTransformInfo;
 
 template <typename ContextT> class GenericUniformityAnalysisImpl;
+template <typename ImplT> struct GenericUniformityAnalysisImplDeleter {
+  // Ugly hack around the fact that recent (> 15.0) clang will run into an
+  // is_invocable() check in some GNU libc++'s unique_ptr implementation
+  // and reject this deleter if you just make it callable with an ImplT *,
+  // whether or not the type of ImplT is spelled out.
+  using pointer = ImplT *;
+  void operator()(ImplT *Impl);
+};
 
 template <typename ContextT> class GenericUniformityInfo {
 public:
@@ -63,12 +71,9 @@ template <typename ContextT> class GenericUniformityInfo {
 
 private:
   using ImplT = GenericUniformityAnalysisImpl<ContextT>;
-  struct ImplDeleter {
-    void operator()(GenericUniformityAnalysisImpl<ContextT> *Impl);
-  };
 
   FunctionT *F;
-  std::unique_ptr<ImplT, ImplDeleter> DA;
+  std::unique_ptr<ImplT, GenericUniformityAnalysisImplDeleter<ImplT>> DA;
 
   GenericUniformityInfo(const GenericUniformityInfo &) = delete;
   GenericUniformityInfo &operator=(const GenericUniformityInfo &) = delete;

llvm/lib/Analysis/UniformityAnalysis.cpp

@@ -87,6 +87,8 @@ bool llvm::GenericUniformityAnalysisImpl<SSAContext>::usesValueFromCycle(
 // This ensures explicit instantiation of
 // GenericUniformityAnalysisImpl::ImplDeleter::operator()
 template class llvm::GenericUniformityInfo<SSAContext>;
+template struct llvm::GenericUniformityAnalysisImplDeleter<
+    llvm::GenericUniformityAnalysisImpl<SSAContext>>;
 
 //===----------------------------------------------------------------------===//
 //  UniformityInfoAnalysis and related pass implementations

llvm/lib/CodeGen/MachineUniformityAnalysis.cpp

@@ -113,6 +113,8 @@ bool llvm::GenericUniformityAnalysisImpl<MachineSSAContext>::usesValueFromCycle(
 // This ensures explicit instantiation of
 // GenericUniformityAnalysisImpl::ImplDeleter::operator()
 template class llvm::GenericUniformityInfo<MachineSSAContext>;
+template struct llvm::GenericUniformityAnalysisImplDeleter<
+    llvm::GenericUniformityAnalysisImpl<MachineSSAContext>>;
 
 MachineUniformityInfo
 llvm::computeMachineUniformityInfo(MachineFunction &F,