Add front-end infrastructure now address space casts are in LLVM IR.

With the introduction of explicit address space casts into LLVM, there's
a need to provide a new cast kind the front-end can create for C/OpenCL/CUDA
and code to produce address space casts from those kinds when appropriate.

Patch by Michele Scandale!

llvm-svn: 197036
diff --git a/clang/lib/CodeGen/CGExpr.cpp b/clang/lib/CodeGen/CGExpr.cpp
index cb990b2..92966d0 100644
--- a/clang/lib/CodeGen/CGExpr.cpp
+++ b/clang/lib/CodeGen/CGExpr.cpp
@@ -2744,6 +2744,7 @@
   case CK_ARCReclaimReturnedObject:
   case CK_ARCExtendBlockObject:
   case CK_CopyAndAutoreleaseBlockObject:
+  case CK_AddressSpaceConversion:
     return EmitUnsupportedLValue(E, "unexpected cast lvalue");
 
   case CK_Dependent:
diff --git a/clang/lib/CodeGen/CGExprAgg.cpp b/clang/lib/CodeGen/CGExprAgg.cpp
index 9d0f3a9..35e6988 100644
--- a/clang/lib/CodeGen/CGExprAgg.cpp
+++ b/clang/lib/CodeGen/CGExprAgg.cpp
@@ -713,6 +713,7 @@
   case CK_CopyAndAutoreleaseBlockObject:
   case CK_BuiltinFnToFnPtr:
   case CK_ZeroToOCLEvent:
+  case CK_AddressSpaceConversion:
     llvm_unreachable("cast kind invalid for aggregate types");
   }
 }
diff --git a/clang/lib/CodeGen/CGExprComplex.cpp b/clang/lib/CodeGen/CGExprComplex.cpp
index 3351738..ded4bb8 100644
--- a/clang/lib/CodeGen/CGExprComplex.cpp
+++ b/clang/lib/CodeGen/CGExprComplex.cpp
@@ -475,6 +475,7 @@
   case CK_CopyAndAutoreleaseBlockObject:
   case CK_BuiltinFnToFnPtr:
   case CK_ZeroToOCLEvent:
+  case CK_AddressSpaceConversion:
     llvm_unreachable("invalid cast kind for complex value");
 
   case CK_FloatingRealToComplex:
diff --git a/clang/lib/CodeGen/CGExprConstant.cpp b/clang/lib/CodeGen/CGExprConstant.cpp
index f4d6861..ad3e1fc 100644
--- a/clang/lib/CodeGen/CGExprConstant.cpp
+++ b/clang/lib/CodeGen/CGExprConstant.cpp
@@ -633,6 +633,9 @@
       return llvm::ConstantStruct::get(STy, Elts);
     }
 
+    case CK_AddressSpaceConversion:
+      return llvm::ConstantExpr::getAddrSpaceCast(C, destType);
+
     case CK_LValueToRValue:
     case CK_AtomicToNonAtomic:
     case CK_NonAtomicToAtomic:
@@ -1062,13 +1065,13 @@
       if (!Offset->isNullValue()) {
         llvm::Constant *Casted = llvm::ConstantExpr::getBitCast(C, Int8PtrTy);
         Casted = llvm::ConstantExpr::getGetElementPtr(Casted, Offset);
-        C = llvm::ConstantExpr::getBitCast(Casted, C->getType());
+        C = llvm::ConstantExpr::getPointerCast(Casted, C->getType());
       }
 
       // Convert to the appropriate type; this could be an lvalue for
       // an integer.
       if (isa<llvm::PointerType>(DestTy))
-        return llvm::ConstantExpr::getBitCast(C, DestTy);
+        return llvm::ConstantExpr::getPointerCast(C, DestTy);
 
       return llvm::ConstantExpr::getPtrToInt(C, DestTy);
     } else {
diff --git a/clang/lib/CodeGen/CGExprScalar.cpp b/clang/lib/CodeGen/CGExprScalar.cpp
index 789c986..d734e3c 100644
--- a/clang/lib/CodeGen/CGExprScalar.cpp
+++ b/clang/lib/CodeGen/CGExprScalar.cpp
@@ -1299,7 +1299,18 @@
   case CK_AnyPointerToBlockPointerCast:
   case CK_BitCast: {
     Value *Src = Visit(const_cast<Expr*>(E));
-    return Builder.CreateBitCast(Src, ConvertType(DestTy));
+    llvm::Type *SrcTy = Src->getType();
+    llvm::Type *DstTy = ConvertType(DestTy);
+    if (SrcTy->isPtrOrPtrVectorTy() && DstTy->isPtrOrPtrVectorTy() && 
+        SrcTy->getPointerAddressSpace() != DstTy->getPointerAddressSpace()) {
+      llvm::Type *MidTy = CGF.CGM.getDataLayout().getIntPtrType(SrcTy);
+      return Builder.CreateIntToPtr(Builder.CreatePtrToInt(Src, MidTy), DstTy);
+    }
+    return Builder.CreateBitCast(Src, DstTy);
+  }
+  case CK_AddressSpaceConversion: {
+    Value *Src = Visit(const_cast<Expr*>(E));
+    return Builder.CreateAddrSpaceCast(Src, ConvertType(DestTy));
   }
   case CK_AtomicToNonAtomic:
   case CK_NonAtomicToAtomic:
@@ -1360,7 +1371,7 @@
 
     // Make sure the array decay ends up being the right type.  This matters if
     // the array type was of an incomplete type.
-    return CGF.Builder.CreateBitCast(V, ConvertType(CE->getType()));
+    return CGF.Builder.CreatePointerCast(V, ConvertType(CE->getType()));
   }
   case CK_FunctionToPointerDecay:
     return EmitLValue(E).getAddress();