Add addrspacecast instruction.

Patch by Michele Scandale!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194760 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index a878ea8..aa96420 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -92,7 +92,7 @@
                                VecIdx);
 
   return Result;
-  
+
 }
 /// Generate a DAG to grab 128-bits from a vector > 128 bits.  This
 /// sets things up to match to an AVX VEXTRACTF128 / VEXTRACTI128
@@ -1765,6 +1765,13 @@
   return true;
 }
 
+bool X86TargetLowering::isNoopAddrSpaceCast(unsigned SrcAS,
+                                            unsigned DestAS) const {
+  assert(SrcAS != DestAS && "Expected different address spaces!");
+
+  return SrcAS < 256 && DestAS < 256;
+}
+
 //===----------------------------------------------------------------------===//
 //               Return Value Calling Convention Implementation
 //===----------------------------------------------------------------------===//