diff --git a/llvm_zluda/src/lib.cpp b/llvm_zluda/src/lib.cpp
index e9b3a52..cff2e31 100644
--- a/llvm_zluda/src/lib.cpp
+++ b/llvm_zluda/src/lib.cpp
@@ -130,4 +130,19 @@ LLVMValueRef LLVMZludaBuildAtomicRMW(LLVMBuilderRef B, LLVMZludaAtomicRMWBinOp o
         context.getOrInsertSyncScopeID(scope)));
 }
 
+LLVMValueRef LLVMZludaBuildAtomicCmpXchg(LLVMBuilderRef B, LLVMValueRef Ptr,
+                                         LLVMValueRef Cmp, LLVMValueRef New,
+                                         char *scope,
+                                         LLVMAtomicOrdering SuccessOrdering,
+                                         LLVMAtomicOrdering FailureOrdering)
+{
+    auto builder = llvm::unwrap(B);
+    LLVMContext &context = builder->getContext();
+    return wrap(builder->CreateAtomicCmpXchg(
+        unwrap(Ptr), unwrap(Cmp), unwrap(New), MaybeAlign(),
+        mapFromLLVMOrdering(SuccessOrdering),
+        mapFromLLVMOrdering(FailureOrdering),
+        context.getOrInsertSyncScopeID(scope)));
+}
+
 LLVM_C_EXTERN_C_END
\ No newline at end of file
diff --git a/llvm_zluda/src/lib.rs b/llvm_zluda/src/lib.rs
index b995cdb..3d941fa 100644
--- a/llvm_zluda/src/lib.rs
+++ b/llvm_zluda/src/lib.rs
@@ -39,4 +39,14 @@ extern "C" {
         scope: *const i8,
         ordering: LLVMAtomicOrdering,
     ) -> LLVMValueRef;
+
+    pub fn LLVMZludaBuildAtomicCmpXchg(
+        B: LLVMBuilderRef,
+        Ptr: LLVMValueRef,
+        Cmp: LLVMValueRef,
+        New: LLVMValueRef,
+        scope: *const i8,
+        SuccessOrdering: LLVMAtomicOrdering,
+        FailureOrdering: LLVMAtomicOrdering,
+    ) -> LLVMValueRef;
 }
diff --git a/ptx/src/pass/emit_llvm.rs b/ptx/src/pass/emit_llvm.rs
index bc5f745..36a9623 100644
--- a/ptx/src/pass/emit_llvm.rs
+++ b/ptx/src/pass/emit_llvm.rs
@@ -26,7 +26,10 @@ use std::ptr;
 use super::*;
 use llvm_zluda::analysis::{LLVMVerifierFailureAction, LLVMVerifyModule};
 use llvm_zluda::bit_writer::LLVMWriteBitcodeToMemoryBuffer;
-use llvm_zluda::{core::*, LLVMAtomicOrdering, LLVMAtomicRMWBinOp, LLVMZludaAtomicRMWBinOp};
+use llvm_zluda::{
+    core::*, LLVMAtomicOrdering, LLVMAtomicRMWBinOp, LLVMZludaAtomicRMWBinOp,
+    LLVMZludaBuildAtomicCmpXchg,
+};
 use llvm_zluda::{prelude::*, LLVMZludaBuildAtomicRMW};
 use llvm_zluda::{LLVMCallConv, LLVMZludaBuildAlloca};
 
@@ -457,7 +460,7 @@ impl<'a, 'input> MethodEmitContext<'a, 'input> {
             ast::Instruction::Selp { data, arguments } => todo!(),
             ast::Instruction::Bar { data, arguments } => todo!(),
             ast::Instruction::Atom { data, arguments } => self.emit_atom(data, arguments),
-            ast::Instruction::AtomCas { data, arguments } => todo!(),
+            ast::Instruction::AtomCas { data, arguments } => self.emit_atom_cas(data, arguments),
             ast::Instruction::Div { data, arguments } => todo!(),
             ast::Instruction::Neg { data, arguments } => todo!(),
             ast::Instruction::Sin { data, arguments } => todo!(),
@@ -724,6 +727,33 @@ impl<'a, 'input> MethodEmitContext<'a, 'input> {
         });
         Ok(())
     }
+
+    fn emit_atom_cas(
+        &mut self,
+        data: ptx_parser::AtomCasDetails,
+        arguments: ptx_parser::AtomCasArgs<SpirvWord>,
+    ) -> Result<(), TranslateError> {
+        let src1 = self.resolver.value(arguments.src1)?;
+        let src2 = self.resolver.value(arguments.src2)?;
+        let src3 = self.resolver.value(arguments.src3)?;
+        let success_ordering = get_ordering(data.semantics);
+        let failure_ordering = get_ordering_failure(data.semantics);
+        let temp = unsafe {
+            LLVMZludaBuildAtomicCmpXchg(
+                self.builder,
+                src1,
+                src2,
+                src3,
+                get_scope(data.scope)?,
+                success_ordering,
+                failure_ordering,
+            )
+        };
+        self.resolver.with_result(arguments.dst, |dst| unsafe {
+            LLVMBuildExtractValue(self.builder, temp, 0, dst)
+        });
+        Ok(())
+    }
 }
 
 fn get_pointer_type<'ctx>(
@@ -753,6 +783,15 @@ fn get_ordering(semantics: ast::AtomSemantics) -> LLVMAtomicOrdering {
     }
 }
 
+fn get_ordering_failure(semantics: ast::AtomSemantics) -> LLVMAtomicOrdering {
+    match semantics {
+        ast::AtomSemantics::Relaxed => LLVMAtomicOrdering::LLVMAtomicOrderingMonotonic,
+        ast::AtomSemantics::Acquire => LLVMAtomicOrdering::LLVMAtomicOrderingAcquire,
+        ast::AtomSemantics::Release => LLVMAtomicOrdering::LLVMAtomicOrderingAcquire,
+        ast::AtomSemantics::AcqRel => LLVMAtomicOrdering::LLVMAtomicOrderingAcquire,
+    }
+}
+
 fn get_type(context: LLVMContextRef, type_: &ast::Type) -> Result<LLVMTypeRef, TranslateError> {
     Ok(match type_ {
         ast::Type::Scalar(scalar) => get_scalar_type(context, *scalar),
diff --git a/ptx/src/pass/mod.rs b/ptx/src/pass/mod.rs
index ff7e2ad..ead747a 100644
--- a/ptx/src/pass/mod.rs
+++ b/ptx/src/pass/mod.rs
@@ -86,8 +86,7 @@ pub fn to_llvm_module2<'input>(ast: ast::Module<'input>) -> Result<Module, Trans
     let directives = normalize_predicates2::run(&mut flat_resolver, directives)?;
     let directives = resolve_function_pointers::run(directives)?;
     let directives = fix_special_registers2::run(&mut flat_resolver, &sreg_map, directives)?;
-    let directives: Vec<Directive2<'_, ptx_parser::Instruction<SpirvWord>, SpirvWord>> =
-        expand_operands::run(&mut flat_resolver, directives)?;
+    let directives = expand_operands::run(&mut flat_resolver, directives)?;
     let directives = deparamize_functions::run(&mut flat_resolver, directives)?;
     let directives = insert_explicit_load_store::run(&mut flat_resolver, directives)?;
     let directives = insert_implicit_conversions2::run(&mut flat_resolver, directives)?;