3 files changed, 28 insertions, 3 deletions

diff --git a/src/wasm/wasm-binary.cpp b/src/wasm/wasm-binary.cpp
index ceb230f73..f98eff670 100644
--- a/src/wasm/wasm-binary.cpp
+++ b/src/wasm/wasm-binary.cpp
@@ -791,6 +791,11 @@ void WasmBinaryWriter::visitLoad(Load *curr) {
       default: WASM_UNREACHABLE();
     }
   } else {
+    if (curr->type == unreachable) {
+      // don't even emit it; we don't know the right type
+      o << int8_t(BinaryConsts::Unreachable);
+      return;
+    }
     o << int8_t(BinaryConsts::AtomicPrefix);
     switch (curr->type) {
       case i32: {
@@ -849,6 +854,11 @@ void WasmBinaryWriter::visitStore(Store *curr) {
       default: abort();
     }
   } else {
+    if (curr->type == unreachable) {
+      // don't even emit it; we don't know the right type
+      o << int8_t(BinaryConsts::Unreachable);
+      return;
+    }
     o << int8_t(BinaryConsts::AtomicPrefix);
     switch (curr->valueType) {
       case i32: {
@@ -881,6 +891,12 @@ void WasmBinaryWriter::visitAtomicRMW(AtomicRMW *curr) {
   recurse(curr->ptr);
   recurse(curr->value);
 
+  if (curr->type == unreachable) {
+    // don't even emit it; we don't know the right type
+    o << int8_t(BinaryConsts::Unreachable);
+    return;
+  }
+
   o << int8_t(BinaryConsts::AtomicPrefix);
 
 #define CASE_FOR_OP(Op) \
@@ -927,6 +943,12 @@ void WasmBinaryWriter::visitAtomicCmpxchg(AtomicCmpxchg *curr) {
   recurse(curr->expected);
   recurse(curr->replacement);
 
+  if (curr->type == unreachable) {
+    // don't even emit it; we don't know the right type
+    o << int8_t(BinaryConsts::Unreachable);
+    return;
+  }
+
   o << int8_t(BinaryConsts::AtomicPrefix);
   switch (curr->type) {
     case i32:
diff --git a/src/wasm/wasm-validator.cpp b/src/wasm/wasm-validator.cpp
index 6d75296a4..5120eea7a 100644
--- a/src/wasm/wasm-validator.cpp
+++ b/src/wasm/wasm-validator.cpp
@@ -487,6 +487,7 @@ void FunctionValidator::visitLoad(Load *curr) {
   validateMemBytes(curr->bytes, curr->type, curr);
   validateAlignment(curr->align, curr->type, curr->bytes, curr->isAtomic, curr);
   shouldBeEqualOrFirstIsUnreachable(curr->ptr->type, i32, curr, "load pointer type must be i32");
+  if (curr->isAtomic) shouldBeFalse(curr->signed_, curr, "atomic loads must be unsigned");
 }
 
 void FunctionValidator::visitStore(Store *curr) {
@@ -502,7 +503,7 @@ void FunctionValidator::visitAtomicRMW(AtomicRMW* curr) {
   shouldBeFalse(!getModule()->memory.shared, curr, "Atomic operation with non-shared memory");
   validateMemBytes(curr->bytes, curr->type, curr);
   shouldBeEqualOrFirstIsUnreachable(curr->ptr->type, i32, curr, "AtomicRMW pointer type must be i32");
-  shouldBeEqualOrFirstIsUnreachable(curr->value->type, curr->type, curr, "AtomicRMW result type must match operand");
+  shouldBeEqualOrFirstIsUnreachable(curr->type, curr->value->type, curr, "AtomicRMW result type must match operand");
   shouldBeIntOrUnreachable(curr->type, curr, "Atomic operations are only valid on int types");
 }
 
@@ -513,8 +514,8 @@ void FunctionValidator::visitAtomicCmpxchg(AtomicCmpxchg* curr) {
   if (curr->expected->type != unreachable && curr->replacement->type != unreachable) {
     shouldBeEqual(curr->expected->type, curr->replacement->type, curr, "cmpxchg operand types must match");
   }
-  shouldBeEqualOrFirstIsUnreachable(curr->expected->type, curr->type, curr, "Cmpxchg result type must match expected");
-  shouldBeEqualOrFirstIsUnreachable(curr->replacement->type, curr->type, curr, "Cmpxchg result type must match replacement");
+  shouldBeEqualOrFirstIsUnreachable(curr->type, curr->expected->type, curr, "Cmpxchg result type must match expected");
+  shouldBeEqualOrFirstIsUnreachable(curr->type, curr->replacement->type, curr, "Cmpxchg result type must match replacement");
   shouldBeIntOrUnreachable(curr->expected->type, curr, "Atomic operations are only valid on int types");
 }
 
diff --git a/src/wasm/wasm.cpp b/src/wasm/wasm.cpp
index f4562fe64..6441991c9 100644
--- a/src/wasm/wasm.cpp
+++ b/src/wasm/wasm.cpp
@@ -390,12 +390,14 @@ void AtomicCmpxchg::finalize() {
 }
 
 void AtomicWait::finalize() {
+  type = i32;
   if (ptr->type == unreachable || expected->type == unreachable || timeout->type == unreachable) {
     type = unreachable;
   }
 }
 
 void AtomicWake::finalize() {
+  type = i32;
   if (ptr->type == unreachable || wakeCount->type == unreachable) {
     type = unreachable;
   }