[WebAssembly] Support for atomic.wait / atomic.wake instructions

Summary:
This adds support for atomic.wait / atomic.wake instructions in the wasm
thread proposal.

Reviewers: dschuff

Subscribers: sbc100, jgravelle-google, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D49395

llvm-svn: 338770
diff --git a/llvm/lib/Target/WebAssembly/WebAssemblySetP2AlignOperands.cpp b/llvm/lib/Target/WebAssembly/WebAssemblySetP2AlignOperands.cpp
index 0d375d5..d8fe1a4 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblySetP2AlignOperands.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblySetP2AlignOperands.cpp
@@ -156,6 +156,9 @@
       case WebAssembly::ATOMIC_RMW_XOR_I64:
       case WebAssembly::ATOMIC_RMW_XCHG_I64:
       case WebAssembly::ATOMIC_RMW_CMPXCHG_I64:
+      case WebAssembly::ATOMIC_NOTIFY:
+      case WebAssembly::ATOMIC_WAIT_I32:
+      case WebAssembly::ATOMIC_WAIT_I64:
         RewriteP2Align(MI, WebAssembly::LoadP2AlignOperandNo);
         break;
       case WebAssembly::STORE_I32: