diff --git a/clang/lib/Basic/Targets/LoongArch.h b/clang/lib/Basic/Targets/LoongArch.h
--- a/clang/lib/Basic/Targets/LoongArch.h
+++ b/clang/lib/Basic/Targets/LoongArch.h
@@ -80,6 +80,9 @@
     }
     return false;
   }
+  void setMaxAtomicWidth() override {
+    MaxAtomicPromoteWidth = MaxAtomicInlineWidth = 32;
+  }
 };
 
 class LLVM_LIBRARY_VISIBILITY LoongArch64TargetInfo
@@ -101,6 +104,9 @@
     }
     return false;
   }
+  void setMaxAtomicWidth() override {
+    MaxAtomicPromoteWidth = MaxAtomicInlineWidth = 64;
+  }
 };
 } // end namespace targets
 } // end namespace clang
diff --git a/clang/test/CodeGen/LoongArch/atomics.c b/clang/test/CodeGen/LoongArch/atomics.c
new file mode 100644
--- /dev/null
+++ b/clang/test/CodeGen/LoongArch/atomics.c
@@ -0,0 +1,45 @@
+// RUN: %clang_cc1 -triple loongarch32 -O1 -emit-llvm %s -o - \
+// RUN:   | FileCheck %s --check-prefix=LA32
+// RUN: %clang_cc1 -triple loongarch64 -O1 -emit-llvm %s -o - \
+// RUN:   | FileCheck %s --check-prefix=LA64
+
+/// This test demonstrates that MaxAtomicInlineWidth is set appropriately.
+
+#include <stdatomic.h>
+#include <stdint.h>
+
+void test_i8_atomics(_Atomic(int8_t) * a, int8_t b) {
+  // LA32: load atomic i8, ptr %a seq_cst, align 1
+  // LA32: store atomic i8 %b, ptr %a seq_cst, align 1
+  // LA32: atomicrmw add ptr %a, i8 %b seq_cst
+  // LA64: load atomic i8, ptr %a seq_cst, align 1
+  // LA64: store atomic i8 %b, ptr %a seq_cst, align 1
+  // LA64: atomicrmw add ptr %a, i8 %b seq_cst
+  __c11_atomic_load(a, memory_order_seq_cst);
+  __c11_atomic_store(a, b, memory_order_seq_cst);
+  __c11_atomic_fetch_add(a, b, memory_order_seq_cst);
+}
+
+void test_i32_atomics(_Atomic(int32_t) * a, int32_t b) {
+  // LA32: load atomic i32, ptr %a seq_cst, align 4
+  // LA32: store atomic i32 %b, ptr %a seq_cst, align 4
+  // LA32: atomicrmw add ptr %a, i32 %b seq_cst
+  // LA64: load atomic i32, ptr %a seq_cst, align 4
+  // LA64: store atomic i32 %b, ptr %a seq_cst, align 4
+  // LA64: atomicrmw add ptr %a, i32 %b seq_cst
+  __c11_atomic_load(a, memory_order_seq_cst);
+  __c11_atomic_store(a, b, memory_order_seq_cst);
+  __c11_atomic_fetch_add(a, b, memory_order_seq_cst);
+}
+
+void test_i64_atomics(_Atomic(int64_t) * a, int64_t b) {
+  // LA32: call i64 @__atomic_load_8
+  // LA32: call void @__atomic_store_8
+  // LA32: call i64 @__atomic_fetch_add_8
+  // LA64: load atomic i64, ptr %a seq_cst, align 8
+  // LA64: store atomic i64 %b, ptr %a seq_cst, align 8
+  // LA64: atomicrmw add ptr %a, i64 %b seq_cst
+  __c11_atomic_load(a, memory_order_seq_cst);
+  __c11_atomic_store(a, b, memory_order_seq_cst);
+  __c11_atomic_fetch_add(a, b, memory_order_seq_cst);
+}
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
@@ -30,16 +30,16 @@
 // LA32: #define __CHAR16_TYPE__ unsigned short
 // LA32: #define __CHAR32_TYPE__ unsigned int
 // LA32: #define __CHAR_BIT__ 8
-// LA32: #define __CLANG_ATOMIC_BOOL_LOCK_FREE 1
-// LA32: #define __CLANG_ATOMIC_CHAR16_T_LOCK_FREE 1
-// LA32: #define __CLANG_ATOMIC_CHAR32_T_LOCK_FREE 1
-// LA32: #define __CLANG_ATOMIC_CHAR_LOCK_FREE 1
-// LA32: #define __CLANG_ATOMIC_INT_LOCK_FREE 1
+// LA32: #define __CLANG_ATOMIC_BOOL_LOCK_FREE 2
+// LA32: #define __CLANG_ATOMIC_CHAR16_T_LOCK_FREE 2
+// LA32: #define __CLANG_ATOMIC_CHAR32_T_LOCK_FREE 2
+// LA32: #define __CLANG_ATOMIC_CHAR_LOCK_FREE 2
+// LA32: #define __CLANG_ATOMIC_INT_LOCK_FREE 2
 // LA32: #define __CLANG_ATOMIC_LLONG_LOCK_FREE 1
-// LA32: #define __CLANG_ATOMIC_LONG_LOCK_FREE 1
-// LA32: #define __CLANG_ATOMIC_POINTER_LOCK_FREE 1
-// LA32: #define __CLANG_ATOMIC_SHORT_LOCK_FREE 1
-// LA32: #define __CLANG_ATOMIC_WCHAR_T_LOCK_FREE 1
+// LA32: #define __CLANG_ATOMIC_LONG_LOCK_FREE 2
+// LA32: #define __CLANG_ATOMIC_POINTER_LOCK_FREE 2
+// LA32: #define __CLANG_ATOMIC_SHORT_LOCK_FREE 2
+// LA32: #define __CLANG_ATOMIC_WCHAR_T_LOCK_FREE 2
 // LA32: #define __DBL_DECIMAL_DIG__ 17
 // LA32: #define __DBL_DENORM_MIN__ 4.9406564584124654e-324
 // LA32: #define __DBL_DIG__ 15
@@ -70,17 +70,17 @@
 // LA32: #define __FLT_MIN_EXP__ (-125)
 // LA32: #define __FLT_MIN__ 1.17549435e-38F
 // LA32: #define __FLT_RADIX__ 2
-// LA32: #define __GCC_ATOMIC_BOOL_LOCK_FREE 1
-// LA32: #define __GCC_ATOMIC_CHAR16_T_LOCK_FREE 1
-// LA32: #define __GCC_ATOMIC_CHAR32_T_LOCK_FREE 1
-// LA32: #define __GCC_ATOMIC_CHAR_LOCK_FREE 1
-// LA32: #define __GCC_ATOMIC_INT_LOCK_FREE 1
+// LA32: #define __GCC_ATOMIC_BOOL_LOCK_FREE 2
+// LA32: #define __GCC_ATOMIC_CHAR16_T_LOCK_FREE 2
+// LA32: #define __GCC_ATOMIC_CHAR32_T_LOCK_FREE 2
+// LA32: #define __GCC_ATOMIC_CHAR_LOCK_FREE 2
+// LA32: #define __GCC_ATOMIC_INT_LOCK_FREE 2
 // LA32: #define __GCC_ATOMIC_LLONG_LOCK_FREE 1
-// LA32: #define __GCC_ATOMIC_LONG_LOCK_FREE 1
-// LA32: #define __GCC_ATOMIC_POINTER_LOCK_FREE 1
-// LA32: #define __GCC_ATOMIC_SHORT_LOCK_FREE 1
+// LA32: #define __GCC_ATOMIC_LONG_LOCK_FREE 2
+// LA32: #define __GCC_ATOMIC_POINTER_LOCK_FREE 2
+// 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 1
+// LA32: #define __GCC_ATOMIC_WCHAR_T_LOCK_FREE 2
 // LA32: #define __ILP32__ 1
 // LA32: #define __INT16_C_SUFFIX__
 // LA32: #define __INT16_FMTd__ "hd"
@@ -342,16 +342,16 @@
 // LA64: #define __CHAR16_TYPE__ unsigned short
 // LA64: #define __CHAR32_TYPE__ unsigned int
 // LA64: #define __CHAR_BIT__ 8
-// LA64: #define __CLANG_ATOMIC_BOOL_LOCK_FREE 1
-// LA64: #define __CLANG_ATOMIC_CHAR16_T_LOCK_FREE 1
-// LA64: #define __CLANG_ATOMIC_CHAR32_T_LOCK_FREE 1
-// LA64: #define __CLANG_ATOMIC_CHAR_LOCK_FREE 1
-// LA64: #define __CLANG_ATOMIC_INT_LOCK_FREE 1
-// LA64: #define __CLANG_ATOMIC_LLONG_LOCK_FREE 1
-// LA64: #define __CLANG_ATOMIC_LONG_LOCK_FREE 1
-// LA64: #define __CLANG_ATOMIC_POINTER_LOCK_FREE 1
-// LA64: #define __CLANG_ATOMIC_SHORT_LOCK_FREE 1
-// LA64: #define __CLANG_ATOMIC_WCHAR_T_LOCK_FREE 1
+// LA64: #define __CLANG_ATOMIC_BOOL_LOCK_FREE 2
+// LA64: #define __CLANG_ATOMIC_CHAR16_T_LOCK_FREE 2
+// LA64: #define __CLANG_ATOMIC_CHAR32_T_LOCK_FREE 2
+// LA64: #define __CLANG_ATOMIC_CHAR_LOCK_FREE 2
+// LA64: #define __CLANG_ATOMIC_INT_LOCK_FREE 2
+// LA64: #define __CLANG_ATOMIC_LLONG_LOCK_FREE 2
+// LA64: #define __CLANG_ATOMIC_LONG_LOCK_FREE 2
+// LA64: #define __CLANG_ATOMIC_POINTER_LOCK_FREE 2
+// LA64: #define __CLANG_ATOMIC_SHORT_LOCK_FREE 2
+// LA64: #define __CLANG_ATOMIC_WCHAR_T_LOCK_FREE 2
 // LA64: #define __DBL_DECIMAL_DIG__ 17
 // LA64: #define __DBL_DENORM_MIN__ 4.9406564584124654e-324
 // LA64: #define __DBL_DIG__ 15
@@ -382,17 +382,17 @@
 // LA64: #define __FLT_MIN_EXP__ (-125)
 // LA64: #define __FLT_MIN__ 1.17549435e-38F
 // LA64: #define __FLT_RADIX__ 2
-// LA64: #define __GCC_ATOMIC_BOOL_LOCK_FREE 1
-// LA64: #define __GCC_ATOMIC_CHAR16_T_LOCK_FREE 1
-// LA64: #define __GCC_ATOMIC_CHAR32_T_LOCK_FREE 1
-// LA64: #define __GCC_ATOMIC_CHAR_LOCK_FREE 1
-// LA64: #define __GCC_ATOMIC_INT_LOCK_FREE 1
-// LA64: #define __GCC_ATOMIC_LLONG_LOCK_FREE 1
-// LA64: #define __GCC_ATOMIC_LONG_LOCK_FREE 1
-// LA64: #define __GCC_ATOMIC_POINTER_LOCK_FREE 1
-// LA64: #define __GCC_ATOMIC_SHORT_LOCK_FREE 1
+// LA64: #define __GCC_ATOMIC_BOOL_LOCK_FREE 2
+// LA64: #define __GCC_ATOMIC_CHAR16_T_LOCK_FREE 2
+// LA64: #define __GCC_ATOMIC_CHAR32_T_LOCK_FREE 2
+// LA64: #define __GCC_ATOMIC_CHAR_LOCK_FREE 2
+// LA64: #define __GCC_ATOMIC_INT_LOCK_FREE 2
+// LA64: #define __GCC_ATOMIC_LLONG_LOCK_FREE 2
+// LA64: #define __GCC_ATOMIC_LONG_LOCK_FREE 2
+// LA64: #define __GCC_ATOMIC_POINTER_LOCK_FREE 2
+// 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 1
+// LA64: #define __GCC_ATOMIC_WCHAR_T_LOCK_FREE 2
 // LA64: #define __INT16_C_SUFFIX__
 // LA64: #define __INT16_FMTd__ "hd"
 // LA64: #define __INT16_FMTi__ "hi"