Revert r168519, "Merge used flags so that we don't have to iterate on isUsed. With this change"

It brought bunch of (possibly false) warnings.

llvm/unittests/VMCore/PassManagerTest.cpp:60:22: warning: variable 'ID' is not needed and will not be emitted [-Wunneeded-internal-declaration]
    char ModuleNDNM::ID=0;
                     ^
llvm/unittests/VMCore/PassManagerTest.cpp:86:22: warning: variable 'ID' is not needed and will not be emitted [-Wunneeded-internal-declaration]
    char ModuleNDM2::ID=0;
                     ^
llvm/unittests/VMCore/PassManagerTest.cpp:106:21: warning: variable 'ID' is not needed and will not be emitted [-Wunneeded-internal-declaration]
    char ModuleDNM::ID=0;
                    ^
llvm/unittests/VMCore/PassManagerTest.cpp:217:16: warning: variable 'initcount' is not needed and will not be emitted [-Wunneeded-internal-declaration]
    int LPass::initcount=0;
               ^
llvm/unittests/VMCore/PassManagerTest.cpp:218:16: warning: variable 'fincount' is not needed and will not be emitted [-Wunneeded-internal-declaration]
    int LPass::fincount=0;
               ^
llvm/unittests/VMCore/PassManagerTest.cpp:259:16: warning: variable 'inited' is not needed and will not be emitted [-Wunneeded-internal-declaration]
    int BPass::inited=0;
               ^
llvm/unittests/VMCore/PassManagerTest.cpp:260:16: warning: variable 'fin' is not needed and will not be emitted [-Wunneeded-internal-declaration]
    int BPass::fin=0;
               ^
llvm/unittests/VMCore/PassManagerTest.cpp:283:24: warning: variable 'ID' is not needed and will not be emitted [-Wunneeded-internal-declaration]
    char OnTheFlyTest::ID=0;
                       ^
8 warnings generated.

llvm-svn: 168549

2 files changed, 7 insertions, 4 deletions

diff --git a/clang/lib/AST/DeclBase.cpp b/clang/lib/AST/DeclBase.cpp
index b04c149deee..7b20e7751ab 100644
--- a/clang/lib/AST/DeclBase.cpp
+++ b/clang/lib/AST/DeclBase.cpp
@@ -261,6 +261,13 @@ bool Decl::isUsed(bool CheckUsedAttr) const {
   if (CheckUsedAttr && hasAttr<UsedAttr>())
     return true;
 
+  // Check redeclarations. We merge attributes, so we don't need to check
+  // attributes in all redeclarations.
+  for (redecl_iterator I = redecls_begin(), E = redecls_end(); I != E; ++I) {
+    if (I->Used)
+      return true;
+  }
+
   return false; 
 }
 
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index e48211032f7..629fccc3064 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -2388,10 +2388,6 @@ bool Sema::MergeCompatibleFunctionDecls(FunctionDecl *New, FunctionDecl *Old,
   if (Old->isPure())
     New->setPure();
 
-  // Merge "used" flag.
-  if (Old->isUsed(false))
-    New->setUsed();
-
   // Merge attributes from the parameters.  These can mismatch with K&R
   // declarations.
   if (New->getNumParams() == Old->getNumParams())