diff --git a/js/src/jit/MIR.h b/js/src/jit/MIR.h
index f57ee6a2dc86..f5bcd99d2075 100644
--- a/js/src/jit/MIR.h
+++ b/js/src/jit/MIR.h
@@ -12635,6 +12635,10 @@ class MAsmJSLoadHeap
 
     bool congruentTo(const MDefinition *ins) const override;
     AliasSet getAliasSet() const override {
+        // When a barrier is needed make the instruction effectful by
+        // giving it a "store" effect.
+        if (barrierBefore_|barrierAfter_)
+            return AliasSet::Store(AliasSet::AsmJSHeap);
         return AliasSet::Load(AliasSet::AsmJSHeap);
     }
     bool mightAlias(const MDefinition *def) const override;