[WebAssembly] Fix __builtin_wasm_tls_base intrinsic

Summary:
Properly generate the outchain for the `__builtin_wasm_tls_base` intrinsic.

Also marked the intrinsic pure, per @sunfish's suggestion.

Reviewers: tlively, aheejin, sbc100, sunfish

Reviewed By: tlively

Subscribers: dschuff, jgravelle-google, hiraditya, cfe-commits, llvm-commits, sunfish

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D64949

llvm-svn: 366499
diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyISelDAGToDAG.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyISelDAGToDAG.cpp
index e57e194..aaf3259 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyISelDAGToDAG.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyISelDAGToDAG.cpp
@@ -235,7 +235,7 @@
       assert(PtrVT == MVT::i32 && "only wasm32 is supported for now");
 
       MachineSDNode *TLSBase = CurDAG->getMachineNode(
-          WebAssembly::GLOBAL_GET_I32, DL, MVT::i32,
+          WebAssembly::GLOBAL_GET_I32, DL, MVT::i32, MVT::Other,
           CurDAG->getTargetExternalSymbol("__tls_base", PtrVT),
           Node->getOperand(0));
       ReplaceNode(Node, TLSBase);