diff --git a/clang/lib/Basic/Targets/LoongArch.cpp b/clang/lib/Basic/Targets/LoongArch.cpp
--- a/clang/lib/Basic/Targets/LoongArch.cpp
+++ b/clang/lib/Basic/Targets/LoongArch.cpp
@@ -158,6 +158,12 @@
   } else if (ABI == "lp64s" || ABI == "ilp32s") {
     Builder.defineMacro("__loongarch_soft_float");
   }
+
+  Builder.defineMacro("__GCC_HAVE_SYNC_COMPARE_AND_SWAP_1");
+  Builder.defineMacro("__GCC_HAVE_SYNC_COMPARE_AND_SWAP_2");
+  Builder.defineMacro("__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4");
+  if (GRLen == 64)
+    Builder.defineMacro("__GCC_HAVE_SYNC_COMPARE_AND_SWAP_8");
 }
 
 static constexpr Builtin::Info BuiltinInfo[] = {
diff --git a/clang/test/Preprocessor/init-loongarch.c b/clang/test/Preprocessor/init-loongarch.c
--- a/clang/test/Preprocessor/init-loongarch.c
+++ b/clang/test/Preprocessor/init-loongarch.c
@@ -81,6 +81,9 @@
 // LA32: #define __GCC_ATOMIC_SHORT_LOCK_FREE 2
 // LA32: #define __GCC_ATOMIC_TEST_AND_SET_TRUEVAL 1
 // LA32: #define __GCC_ATOMIC_WCHAR_T_LOCK_FREE 2
+// LA32: #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_1 1
+// LA32: #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_2 1
+// LA32: #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4 1
 // LA32: #define __ILP32__ 1
 // LA32: #define __INT16_C_SUFFIX__
 // LA32: #define __INT16_FMTd__ "hd"
@@ -394,6 +397,10 @@
 // LA64: #define __GCC_ATOMIC_SHORT_LOCK_FREE 2
 // LA64: #define __GCC_ATOMIC_TEST_AND_SET_TRUEVAL 1
 // LA64: #define __GCC_ATOMIC_WCHAR_T_LOCK_FREE 2
+// LA64: #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_1 1
+// LA64: #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_2 1
+// LA64: #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4 1
+// LA64: #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_8 1
 // LA64: #define __INT16_C_SUFFIX__
 // LA64: #define __INT16_FMTd__ "hd"
 // LA64: #define __INT16_FMTi__ "hi"
diff --git a/clang/test/Preprocessor/predefined-arch-macros.c b/clang/test/Preprocessor/predefined-arch-macros.c
--- a/clang/test/Preprocessor/predefined-arch-macros.c
+++ b/clang/test/Preprocessor/predefined-arch-macros.c
@@ -4372,3 +4372,20 @@
 // CHECK_WASM_ATOMICS: #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_2 1
 // CHECK_WASM_ATOMICS: #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4 1
 // CHECK_WASM_ATOMICS: #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_8 1
+
+// Begin LoongArch tests ----------------
+
+// RUN: %clang -E -dM %s -o - 2>&1 \
+// RUN:     --target=loongarch32-unknown-linux-gnu \
+// RUN:   | FileCheck -match-full-lines %s -check-prefix=CHECK_LA32_ATOMICS
+// CHECK_LA32_ATOMICS: #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_1 1
+// CHECK_LA32_ATOMICS: #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_2 1
+// CHECK_LA32_ATOMICS: #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4 1
+
+// RUN: %clang -E -dM %s -o - 2>&1 \
+// RUN:     --target=loongarch64-unknown-linux-gnu \
+// RUN:   | FileCheck -match-full-lines %s -check-prefix=CHECK_LA64_ATOMICS
+// CHECK_LA64_ATOMICS: #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_1 1
+// CHECK_LA64_ATOMICS: #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_2 1
+// CHECK_LA64_ATOMICS: #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4 1
+// CHECK_LA64_ATOMICS: #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_8 1