[WebAssembly] Add sign extend instructions from atomics proposal

Select them from ISD::SIGN_EXTEND_INREG

Differential Revision: https://reviews.llvm.org/D37603

remove spurious change

llvm-svn: 313101
diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp
index 5615ec1..91db3da 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp
@@ -115,8 +115,12 @@
 
   // As a special case, these operators use the type to mean the type to
   // sign-extend from.
-  for (auto T : {MVT::i1, MVT::i8, MVT::i16, MVT::i32})
-    setOperationAction(ISD::SIGN_EXTEND_INREG, T, Expand);
+  setOperationAction(ISD::SIGN_EXTEND_INREG, MVT::i1, Expand);
+  if (!Subtarget->hasAtomics()) {
+    // The Atomics feature includes signext intructions.
+    for (auto T : {MVT::i8, MVT::i16, MVT::i32})
+      setOperationAction(ISD::SIGN_EXTEND_INREG, T, Expand);
+  }
 
   // Dynamic stack allocation: use the default expansion.
   setOperationAction(ISD::STACKSAVE, MVT::Other, Expand);