[OpenCL] Handle AddressSpaceConversion when target address space does not change.

In codegen different address spaces may be mapped to the same address
space for a target, e.g. in x86/x86-64 all address spaces are mapped
to 0. Therefore AddressSpaceConversion should be translated by
CreatePointerBitCastOrAddrSpaceCast instead of CreateAddrSpaceCast.

Differential Revision: http://reviews.llvm.org/D18713

llvm-svn: 266107

1 files changed, 4 insertions, 1 deletions

diff --git a/clang/lib/CodeGen/CGExprScalar.cpp b/clang/lib/CodeGen/CGExprScalar.cpp
index 76bfc57cee9..1fd79d0e0ed 100644
--- a/clang/lib/CodeGen/CGExprScalar.cpp
+++ b/clang/lib/CodeGen/CGExprScalar.cpp
@@ -1411,7 +1411,10 @@ Value *ScalarExprEmitter::VisitCastExpr(CastExpr *CE) {
   }
   case CK_AddressSpaceConversion: {
     Value *Src = Visit(const_cast<Expr*>(E));
-    return Builder.CreateAddrSpaceCast(Src, ConvertType(DestTy));
+    // Since target may map different address spaces in AST to the same address
+    // space, an address space conversion may end up as a bitcast.
+    return Builder.CreatePointerBitCastOrAddrSpaceCast(Src,
+                                                       ConvertType(DestTy));
   }
   case CK_AtomicToNonAtomic:
   case CK_NonAtomicToAtomic: