1 files changed, 29 insertions, 17 deletions

diff --git a/clang/lib/Sema/SemaType.cpp b/clang/lib/Sema/SemaType.cpp
index 9ee947b80a3..978c1cc0158 100644
--- a/clang/lib/Sema/SemaType.cpp
+++ b/clang/lib/Sema/SemaType.cpp
@@ -5758,14 +5758,6 @@ QualType Sema::BuildAddressSpaceAttr(QualType &T, Expr *AddrSpace,
                                      SourceLocation AttrLoc) {
   if (!AddrSpace->isValueDependent()) { 
 
-    // If this type is already address space qualified, reject it.
-    // ISO/IEC TR 18037 S5.3 (amending C99 6.7.3): "No type shall be qualified
-    // by qualifiers for two or more different address spaces."
-    if (T.getAddressSpace() != LangAS::Default) {
-      Diag(AttrLoc, diag::err_attribute_address_multiple_qualifiers);
-      return QualType();
-    }
-
     llvm::APSInt addrSpace(32);
     if (!AddrSpace->isIntegerConstantExpr(addrSpace, Context)) {
       Diag(AttrLoc, diag::err_attribute_argument_type)
@@ -5796,6 +5788,20 @@ QualType Sema::BuildAddressSpaceAttr(QualType &T, Expr *AddrSpace,
     LangAS ASIdx =
         getLangASFromTargetAS(static_cast<unsigned>(addrSpace.getZExtValue()));
 
+    // If this type is already address space qualified with a different
+    // address space, reject it.
+    // ISO/IEC TR 18037 S5.3 (amending C99 6.7.3): "No type shall be qualified
+    // by qualifiers for two or more different address spaces."
+    if (T.getAddressSpace() != LangAS::Default) {
+      if (T.getAddressSpace() != ASIdx) {
+        Diag(AttrLoc, diag::err_attribute_address_multiple_qualifiers);
+        return QualType();
+      } else
+        // Emit a warning if they are identical; it's likely unintended.
+        Diag(AttrLoc,
+             diag::warn_attribute_address_multiple_identical_qualifiers);
+    }
+
     return Context.getAddrSpaceQualType(T, ASIdx);
   }
 
@@ -5817,15 +5823,6 @@ QualType Sema::BuildAddressSpaceAttr(QualType &T, Expr *AddrSpace,
 /// space for the type.
 static void HandleAddressSpaceTypeAttribute(QualType &Type,
                                             const AttributeList &Attr, Sema &S){
-  // If this type is already address space qualified, reject it.
-  // ISO/IEC TR 18037 S5.3 (amending C99 6.7.3): "No type shall be qualified by
-  // qualifiers for two or more different address spaces."
-  if (Type.getAddressSpace() != LangAS::Default) {
-    S.Diag(Attr.getLoc(), diag::err_attribute_address_multiple_qualifiers);
-    Attr.setInvalid();
-    return;
-  }
-
   // ISO/IEC TR 18037 S5.3 (amending C99 6.7.3): "A function type shall not be
   // qualified by an address-space qualifier."
   if (Type->isFunctionType()) {
@@ -5888,6 +5885,21 @@ static void HandleAddressSpaceTypeAttribute(QualType &Type,
       llvm_unreachable("Invalid address space");
     }
 
+    // If this type is already address space qualified with a different
+    // address space, reject it.
+    // ISO/IEC TR 18037 S5.3 (amending C99 6.7.3): "No type shall be qualified by
+    // qualifiers for two or more different address spaces."
+    if (Type.getAddressSpace() != LangAS::Default) {
+      if (Type.getAddressSpace() != ASIdx) {
+        S.Diag(Attr.getLoc(), diag::err_attribute_address_multiple_qualifiers);
+        Attr.setInvalid();
+        return;
+      } else
+        // Emit a warning if they are identical; it's likely unintended.
+        S.Diag(Attr.getLoc(),
+               diag::warn_attribute_address_multiple_identical_qualifiers);
+    }
+
     Type = S.Context.getAddrSpaceQualType(Type, ASIdx);
   }
 }