4 files changed, 20 insertions, 7 deletions
diff --git a/clang/lib/AST/ASTContext.cpp b/clang/lib/AST/ASTContext.cpp
index 5463b7b7b05..c6e2c20df7d 100644
--- a/clang/lib/AST/ASTContext.cpp
+++ b/clang/lib/AST/ASTContext.cpp
@@ -696,7 +696,10 @@ CharUnits ASTContext::getDeclAlign(const Decl *D, bool RefAsPointee) const {
         // Walk through any array types while we're at it.
         T = getBaseElementType(arrayType);
       }
-      Align = std::max(Align, getPreferredTypeAlign(T.getTypePtr()));
+      if (Target.usePreferredTypeAlign())
+        Align = std::max(Align, getPreferredTypeAlign(T.getTypePtr()));
+      else
+        Align = std::max(Align, getTypeAlign(T.getTypePtr()));
     }
 
     // Fields can be subject to extra alignment constraints, like if
diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index fdcff0a4daf..1435627562f 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -1592,10 +1592,15 @@ CharUnits IntExprEvaluator::GetAlignOfType(QualType T) {
   //   result shall be the alignment of the referenced type."
   if (const ReferenceType *Ref = T->getAs<ReferenceType>())
     T = Ref->getPointeeType();
-
-  // __alignof is defined to return the preferred alignment.
-  return Info.Ctx.toCharUnitsFromBits(
-    Info.Ctx.getPreferredTypeAlign(T.getTypePtr()));
+ 
+  // __alignof defaults to returning the preferred alignment, but
+  // can be overridden by the specific target.
+  if (Info.Ctx.Target.usePreferredTypeAlign())
+    return Info.Ctx.toCharUnitsFromBits(
+      Info.Ctx.getPreferredTypeAlign(T.getTypePtr()));
+  else
+    return Info.Ctx.toCharUnitsFromBits(
+      Info.Ctx.getTypeAlign(T.getTypePtr()));
 }
 
 CharUnits IntExprEvaluator::GetAlignOfExpr(const Expr *E) {
diff --git a/clang/lib/Basic/TargetInfo.cpp b/clang/lib/Basic/TargetInfo.cpp
index 7ea51467c18..c7a87b20eb8 100644
--- a/clang/lib/Basic/TargetInfo.cpp
+++ b/clang/lib/Basic/TargetInfo.cpp
@@ -65,6 +65,9 @@ TargetInfo::TargetInfo(const std::string &T) : Triple(T) {
   // Default to no types using fpret.
   RealTypeUsesObjCFPRet = 0;
 
+  // Default to using preferred type alignment.
+  UsePreferredTypeAlign = true;
+
   // Default to using the Itanium ABI.
   CXXABI = CXXABI_Itanium;
 
diff --git a/clang/lib/Basic/Targets.cpp b/clang/lib/Basic/Targets.cpp
index 3aebc41d713..53f5c0abafc 100644
--- a/clang/lib/Basic/Targets.cpp
+++ b/clang/lib/Basic/Targets.cpp
@@ -1978,11 +1978,13 @@ public:
                              "v64:32:64-v128:32:128-a0:0:32-n32");
       }
 
-      // FIXME: Override "preferred align" for double and long long.
+      // Default to using minimum alignment, not preferred.
+      UsePreferredTypeAlign = false;
     } else if (Name == "aapcs") {
       // FIXME: Enumerated types are variable width in straight AAPCS.
+
     } else if (Name == "aapcs-linux") {
-      ;
+
     } else
       return false;