[WebAssembly] Suffix output operands with '='.

This distinguishes input operands from output operands. This is something of
a syntactic experiment to see whether the mild amount of clutter this adds is
outweighed by the extra information it conveys to the reader.

llvm-svn: 253922
diff --git a/llvm/lib/Target/WebAssembly/InstPrinter/WebAssemblyInstPrinter.cpp b/llvm/lib/Target/WebAssembly/InstPrinter/WebAssemblyInstPrinter.cpp
index a53a7cd..d5ffcbb 100644
--- a/llvm/lib/Target/WebAssembly/InstPrinter/WebAssemblyInstPrinter.cpp
+++ b/llvm/lib/Target/WebAssembly/InstPrinter/WebAssemblyInstPrinter.cpp
@@ -90,6 +90,9 @@
       O << "$push" << (WAReg & INT32_MAX);
     else
       O << "$discard";
+    // Add a '=' suffix if this is a def.
+    if (OpNo < MII.get(MI->getOpcode()).getNumDefs())
+      O << '=';
   } else if (Op.isImm()) {
     switch (MI->getOpcode()) {
     case WebAssembly::PARAM: