diff --git a/src/passes/MergeBlocks.cpp b/src/passes/MergeBlocks.cpp
index 3013f67ac9b..7010d6d15f7 100644
--- a/src/passes/MergeBlocks.cpp
+++ b/src/passes/MergeBlocks.cpp
@@ -498,29 +498,11 @@ struct MergeBlocks
   // )
   // at which point the block is on the outside and potentially mergeable with
   // an outer block
-  Block* optimize(Expression* curr,
-                  Expression*& child,
-                  Block* outer = nullptr,
-                  Expression** dependency1 = nullptr,
-                  Expression** dependency2 = nullptr) {
+  Block*
+  optimize(Expression* curr, Expression*& child, Block* outer = nullptr) {
     if (!child) {
       return outer;
     }
-    if ((dependency1 && *dependency1) || (dependency2 && *dependency2)) {
-      // there are dependencies, things we must be reordered through. make sure
-      // no problems there
-      EffectAnalyzer childEffects(getPassOptions(), *getModule(), child);
-      if (dependency1 && *dependency1 &&
-          EffectAnalyzer(getPassOptions(), *getModule(), *dependency1)
-            .invalidates(childEffects)) {
-        return outer;
-      }
-      if (dependency2 && *dependency2 &&
-          EffectAnalyzer(getPassOptions(), *getModule(), *dependency2)
-            .invalidates(childEffects)) {
-        return outer;
-      }
-    }
     if (auto* block = child->dynCast<Block>()) {
       if (!block->name.is() && block->list.size() >= 2) {
         auto* back = block->list.back();
@@ -665,7 +647,7 @@ struct MergeBlocks
         EffectAnalyzer blockChildEffects(
           getPassOptions(), *getModule(), blockChild);
         for (auto& effects : childEffects) {
-          if (blockChildEffects.invalidates(effects)) {
+          if (effects.orderedBefore(blockChildEffects)) {
             fail = true;
             break;
           }
diff --git a/test/lit/passes/merge-blocks-atomics.wast b/test/lit/passes/merge-blocks-atomics.wast
new file mode 100644
index 00000000000..cd5ce550644
--- /dev/null
+++ b/test/lit/passes/merge-blocks-atomics.wast
@@ -0,0 +1,91 @@
+;; NOTE: Assertions have been generated by update_lit_checks.py and should not be edited.
+;; RUN: wasm-opt %s --merge-blocks -all -S -o - | filecheck %s
+
+(module
+  ;; CHECK:      (type $struct (shared (struct (field (mut i32)))))
+  (type $struct (shared (struct (field (mut i32)))))
+
+  ;; CHECK:      (memory $mem 1 1 shared)
+  (memory $mem 1 1 shared)
+
+  ;; CHECK:      (func $foo (type $2) (param $0 i32) (param $1 i32)
+  ;; CHECK-NEXT: )
+  (func $foo (param i32 i32))
+
+  ;; Test 1: Disallowed reordering (GC read NOT moved before Wasm acquire load)
+  ;; Child 0 is named, so it is NOT optimized and its effects (acquire load) are left behind.
+  ;; Child 1 tries to move the GC read out, which should be blocked because it cannot move before the acquire load.
+  ;; CHECK:      (func $disallowed (type $1) (param $x (ref $struct))
+  ;; CHECK-NEXT:  (call $foo
+  ;; CHECK-NEXT:   (block $label1 (result i32)
+  ;; CHECK-NEXT:    (drop
+  ;; CHECK-NEXT:     (i32.atomic.load acqrel
+  ;; CHECK-NEXT:      (i32.const 0)
+  ;; CHECK-NEXT:     )
+  ;; CHECK-NEXT:    )
+  ;; CHECK-NEXT:    (i32.const 0)
+  ;; CHECK-NEXT:   )
+  ;; CHECK-NEXT:   (block (result i32)
+  ;; CHECK-NEXT:    (drop
+  ;; CHECK-NEXT:     (struct.get $struct 0
+  ;; CHECK-NEXT:      (local.get $x)
+  ;; CHECK-NEXT:     )
+  ;; CHECK-NEXT:    )
+  ;; CHECK-NEXT:    (i32.const 0)
+  ;; CHECK-NEXT:   )
+  ;; CHECK-NEXT:  )
+  ;; CHECK-NEXT: )
+  (func $disallowed (param $x (ref $struct))
+    (call $foo
+      ;; Child 0: Left behind (named block)
+      (block $label1 (result i32)
+        (drop (i32.atomic.load acqrel (i32.const 0)))
+        (i32.const 0)
+      )
+      ;; Child 1: Tries to move out
+      (block (result i32)
+        ;; A: GC read
+        (drop (struct.get $struct 0 (local.get $x)))
+        ;; B
+        (i32.const 0)
+      )
+    )
+  )
+
+  ;; Test 2: Allowed reordering (GC read moved before Wasm release store)
+  ;; Child 0 is named, so it is NOT optimized and its effects (release store) are left behind.
+  ;; Child 1 tries to move the GC read out, which should be ALLOWED because it can move before the release store.
+  ;; CHECK:      (func $allowed (type $1) (param $x (ref $struct))
+  ;; CHECK-NEXT:  (drop
+  ;; CHECK-NEXT:   (struct.get $struct 0
+  ;; CHECK-NEXT:    (local.get $x)
+  ;; CHECK-NEXT:   )
+  ;; CHECK-NEXT:  )
+  ;; CHECK-NEXT:  (call $foo
+  ;; CHECK-NEXT:   (block $label2 (result i32)
+  ;; CHECK-NEXT:    (i32.atomic.store acqrel
+  ;; CHECK-NEXT:     (i32.const 0)
+  ;; CHECK-NEXT:     (i32.const 42)
+  ;; CHECK-NEXT:    )
+  ;; CHECK-NEXT:    (i32.const 0)
+  ;; CHECK-NEXT:   )
+  ;; CHECK-NEXT:   (i32.const 0)
+  ;; CHECK-NEXT:  )
+  ;; CHECK-NEXT: )
+  (func $allowed (param $x (ref $struct))
+    (call $foo
+      ;; Child 0: Left behind (named block)
+      (block $label2 (result i32)
+        (i32.atomic.store acqrel (i32.const 0) (i32.const 42))
+        (i32.const 0)
+      )
+      ;; Child 1: Tries to move out
+      (block (result i32)
+        ;; A: GC read
+        (drop (struct.get $struct 0 (local.get $x)))
+        ;; B
+        (i32.const 0)
+      )
+    )
+  )
+)