Revert r311857 "Emit static constexpr member as available_externally definition"

It caused PR759744.

> Emit static constexpr member as available_externally definition
>
> By exposing the constant initializer, the optimizer can fold many
> of these constructs.
>
> Differential Revision: https://reviews.llvm.org/D34992

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@311898 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 0 insertions, 22 deletions

diff --git a/lib/CodeGen/CodeGenModule.cpp b/lib/CodeGen/CodeGenModule.cpp
index 5feb6b4d76..c726d90f2e 100644
--- a/lib/CodeGen/CodeGenModule.cpp
+++ b/lib/CodeGen/CodeGenModule.cpp
@@ -2437,28 +2437,6 @@ CodeGenModule::GetOrCreateLLVMGlobal(StringRef MangledName,
         D->getType().isConstant(Context) &&
         isExternallyVisible(D->getLinkageAndVisibility().getLinkage()))
       GV->setSection(".cp.rodata");
-
-    // Check if we a have a const declaration with an initializer, we may be
-    // able to emit it as available_externally to expose it's value to the
-    // optimizer.
-    if (Context.getLangOpts().CPlusPlus && GV->hasExternalLinkage() &&
-        D->getType().isConstQualified() && !GV->hasInitializer() &&
-        !D->hasDefinition() && D->hasInit() && !D->hasAttr<DLLImportAttr>()) {
-      const auto *Record =
-          Context.getBaseElementType(D->getType())->getAsCXXRecordDecl();
-      bool HasMutableFields = Record && Record->hasMutableFields();
-      if (!HasMutableFields) {
-        const VarDecl *InitDecl;
-        const Expr *InitExpr = D->getAnyInitializer(InitDecl);
-        if (InitExpr) {
-          GV->setConstant(true);
-          GV->setLinkage(llvm::GlobalValue::AvailableExternallyLinkage);
-          ConstantEmitter emitter(*this);
-          GV->setInitializer(emitter.tryEmitForInitializer(*InitDecl));
-          emitter.finalize(GV);
-        }
-      }
-    }
   }
 
   auto ExpectedAS =