Propagate alignment for _Complex

lib/CodeGen/CGExprComplex.cpp

Index: lib/CodeGen/CGExprComplex.cpp
diff --git a/lib/CodeGen/CGExprComplex.cpp b/lib/CodeGen/CGExprComplex.cpp
index 0a53d4f1277f3493e8e6a206f16a3b26c5d6788d..0067c38285a0496b6c6a23ee98b604fe5e0c05b3 100644
--- a/lib/CodeGen/CGExprComplex.cpp
+++ b/lib/CodeGen/CGExprComplex.cpp
@@ -18,6 +18,7 @@
 #include "llvm/ADT/SmallString.h"
 #include "llvm/IR/Constants.h"
 #include "llvm/IR/Function.h"
+#include "llvm/IR/GlobalValue.h" // @LOCALMOD not needed after merge
 using namespace clang;
 using namespace CodeGen;
 
@@ -291,17 +292,27 @@ public:
 ComplexPairTy ComplexExprEmitter::EmitLoadOfComplex(llvm::Value *SrcPtr,
                                                     bool isVolatile) {
   llvm::Value *Real=0, *Imag=0;
+  // @LOCALMOD-START I submitted a fix upstream for this issue, but the code
+  //                 was re-written to use LValue instead of Value, so this
+  //                 fix will be wrong after the merge.
+  //                 We should cherry-pick my fix, which is past 3.3.
+  unsigned Align = 0;
+
+  if (llvm::GlobalValue *GV = dyn_cast<llvm::GlobalValue>(SrcPtr))
+    Align = GV->getAlignment();
 
   if (!IgnoreReal || isVolatile) {
     llvm::Value *RealP = Builder.CreateStructGEP(SrcPtr, 0,
                                                  SrcPtr->getName() + ".realp");
-    Real = Builder.CreateLoad(RealP, isVolatile, SrcPtr->getName() + ".real");
+    Real = Builder.CreateAlignedLoad(RealP, Align, isVolatile,
+                                     SrcPtr->getName() + ".real");
   }
 
   if (!IgnoreImag || isVolatile) {
     llvm::Value *ImagP = Builder.CreateStructGEP(SrcPtr, 1,
                                                  SrcPtr->getName() + ".imagp");
-    Imag = Builder.CreateLoad(ImagP, isVolatile, SrcPtr->getName() + ".imag");
+    Imag = Builder.CreateAlignedLoad(ImagP, Align, isVolatile,
+                                     SrcPtr->getName() + ".imag");
   }
   return ComplexPairTy(Real, Imag);
 }
@@ -312,9 +323,14 @@ void ComplexExprEmitter::EmitStoreOfComplex(ComplexPairTy Val, llvm::Value *Ptr,
                                             bool isVolatile) {
   llvm::Value *RealPtr = Builder.CreateStructGEP(Ptr, 0, "real");
   llvm::Value *ImagPtr = Builder.CreateStructGEP(Ptr, 1, "imag");
+  unsigned Align = 0;
+
+  if (llvm::GlobalValue *GV = dyn_cast<llvm::GlobalValue>(Ptr))
+    Align = GV->getAlignment();
 
-  Builder.CreateStore(Val.first, RealPtr, isVolatile);
-  Builder.CreateStore(Val.second, ImagPtr, isVolatile);
+  Builder.CreateAlignedStore(Val.first, RealPtr, Align, isVolatile);
+  Builder.CreateAlignedStore(Val.second, ImagPtr, Align, isVolatile);
+  // @LOCALMOD-END
 }