[wasm] Forbid sign mismatch in asm typer.

src/typing-asm.cc

Index: src/typing-asm.cc
diff --git a/src/typing-asm.cc b/src/typing-asm.cc
index 2390e7e7b12a824229e8d68768896c35791836d4..085c544a6084f14891ddd76259982c6e8c122382 100644
--- a/src/typing-asm.cc
+++ b/src/typing-asm.cc
@@ -1299,6 +1299,16 @@ void AsmTyper::VisitBinaryOperation(BinaryOperation* expr) {
               FAIL(expr, "too many consecutive multiplicative ops");
             }
           }
+          if (expr->op() == Token::MOD || expr->op() == Token::DIV) {
+            if (!((left_type->Is(cache_.kAsmSigned) &&
+                   right_type->Is(cache_.kAsmSigned)) ||
+                  (left_type->Is(cache_.kAsmUnsigned) &&
+                   right_type->Is(cache_.kAsmUnsigned)))) {
+              FAIL(expr,
+                   "left and right side of integer / or % "
+                   "must match and be signed or unsigned");
+            }
+          }
           RECURSE(IntersectResult(expr, cache_.kAsmInt));
           return;
         }