1 files changed, 23 insertions, 3 deletions
diff --git a/src/wast-parser.cc b/src/wast-parser.cc
index 353eed36..f2fcf73e 100644
--- a/src/wast-parser.cc
+++ b/src/wast-parser.cc
@@ -583,8 +583,8 @@ TokenTypePair WastParser::PeekPair() {
   return TokenTypePair{{Peek(), Peek(1)}};
 }
 
-bool WastParser::PeekMatch(TokenType type) {
-  return Peek() == type;
+bool WastParser::PeekMatch(TokenType type, size_t n) {
+  return Peek(n) == type;
 }
 
 bool WastParser::PeekMatchLpar(TokenType type) {
@@ -1945,6 +1945,26 @@ Result WastParser::ParseSIMDLoadStoreInstr(Location loc,
                                            std::unique_ptr<Expr>* out_expr) {
   ErrorUnlessOpcodeEnabled(token);
 
+  Var memidx(0, loc);
+
+  if (options_->features.multi_memory_enabled()) {
+    // We have to be a little careful when reading the memeory index.
+    // If there is just a single integer folloing the instruction that
+    // represents the lane index, so we check for either a pair of intergers
+    // or an integers followed by offset= or align=.
+    bool try_read_mem_index = true;
+    if (PeekMatch(TokenType::Nat)) {
+      // The next token could be a memory index or a lane index
+      if (!PeekMatch(TokenType::OffsetEqNat, 1) &&
+          !PeekMatch(TokenType::AlignEqNat, 1) &&
+          !PeekMatch(TokenType::Nat, 1)) {
+        try_read_mem_index = false;
+      }
+    }
+    if (try_read_mem_index) {
+      CHECK_RESULT(ParseMemidx(loc, &memidx));
+    }
+  }
   Address offset;
   Address align;
   ParseOffsetOpt(&offset);
@@ -1957,7 +1977,7 @@ Result WastParser::ParseSIMDLoadStoreInstr(Location loc,
     return Result::Error;
   }
 
-  out_expr->reset(new T(token.opcode(), align, offset, lane_idx, loc));
+  out_expr->reset(new T(token.opcode(), memidx, align, offset, lane_idx, loc));
   return Result::Ok;
 }