diff --git a/clang/lib/Basic/Targets/Hexagon.cpp b/clang/lib/Basic/Targets/Hexagon.cpp
--- a/clang/lib/Basic/Targets/Hexagon.cpp
+++ b/clang/lib/Basic/Targets/Hexagon.cpp
@@ -102,6 +102,11 @@
 
   std::string NumPhySlots = isTinyCore() ? "3" : "4";
   Builder.defineMacro("__HEXAGON_PHYSICAL_SLOTS__", NumPhySlots);
+
+  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");
+  Builder.defineMacro("__GCC_HAVE_SYNC_COMPARE_AND_SWAP_8");
 }
 
 bool HexagonTargetInfo::initFeatureMap(
diff --git a/clang/lib/Basic/Targets/VE.cpp b/clang/lib/Basic/Targets/VE.cpp
--- a/clang/lib/Basic/Targets/VE.cpp
+++ b/clang/lib/Basic/Targets/VE.cpp
@@ -38,6 +38,11 @@
   // FIXME: define __FAST_MATH__ 1 if -ffast-math is enabled
   // FIXME: define __OPTIMIZE__ n if -On is enabled
   // FIXME: define __VECTOR__ n 1 if automatic vectorization is enabled
+
+  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");
+  Builder.defineMacro("__GCC_HAVE_SYNC_COMPARE_AND_SWAP_8");
 }
 
 ArrayRef<Builtin::Info> VETargetInfo::getTargetBuiltins() const {
diff --git a/clang/lib/Basic/Targets/WebAssembly.cpp b/clang/lib/Basic/Targets/WebAssembly.cpp
--- a/clang/lib/Basic/Targets/WebAssembly.cpp
+++ b/clang/lib/Basic/Targets/WebAssembly.cpp
@@ -96,6 +96,11 @@
     Builder.defineMacro("__wasm_reference_types__");
   if (HasExtendedConst)
     Builder.defineMacro("__wasm_extended_const__");
+
+  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");
+  Builder.defineMacro("__GCC_HAVE_SYNC_COMPARE_AND_SWAP_8");
 }
 
 void WebAssemblyTargetInfo::setSIMDLevel(llvm::StringMap<bool> &Features,
diff --git a/clang/test/Preprocessor/init.c b/clang/test/Preprocessor/init.c
--- a/clang/test/Preprocessor/init.c
+++ b/clang/test/Preprocessor/init.c
@@ -1597,6 +1597,10 @@
 // WEBASSEMBLY-NEXT:#define __GCC_ATOMIC_SHORT_LOCK_FREE 2
 // WEBASSEMBLY-NEXT:#define __GCC_ATOMIC_TEST_AND_SET_TRUEVAL 1
 // WEBASSEMBLY-NEXT:#define __GCC_ATOMIC_WCHAR_T_LOCK_FREE 2
+// WEBASSEMBLY-NEXT:#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_1 1
+// WEBASSEMBLY-NEXT:#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_2 1
+// WEBASSEMBLY-NEXT:#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4 1
+// WEBASSEMBLY-NEXT:#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_8 1
 // WEBASSEMBLY-NEXT:#define __GNUC_MINOR__ {{.*}}
 // WEBASSEMBLY-NEXT:#define __GNUC_PATCHLEVEL__ {{.*}}
 // WEBASSEMBLY-NEXT:#define __GNUC_STDC_INLINE__ 1
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
@@ -4330,3 +4330,39 @@
 // CHECK_M68K_68020_ATOMICS: #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_1 1
 // CHECK_M68K_68020_ATOMICS: #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_2 1
 // CHECK_M68K_68020_ATOMICS: #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4 1
+
+// Begin Hexagon tests ----------------
+
+// RUN: %clang -E -dM %s -o - 2>&1 \
+// RUN:     --target=hexagon-unknown-linux \
+// RUN:   | FileCheck -match-full-lines %s -check-prefix=CHECK_HEXAGON_ATOMICS
+
+// CHECK_HEXAGON_ATOMICS: #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_1 1
+// CHECK_HEXAGON_ATOMICS: #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_2 1
+// CHECK_HEXAGON_ATOMICS: #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4 1
+// CHECK_HEXAGON_ATOMICS: #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_8 1
+
+// Begin VE tests ----------------
+
+// RUN: %clang -E -dM %s -o - 2>&1 \
+// RUN:     --target=ve-unknown-linux \
+// RUN:   | FileCheck -match-full-lines %s -check-prefix=CHECK_VE_ATOMICS
+
+// CHECK_VE_ATOMICS: #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_1 1
+// CHECK_VE_ATOMICS: #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_2 1
+// CHECK_VE_ATOMICS: #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4 1
+// CHECK_VE_ATOMICS: #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_8 1
+
+// Begin WebAssembly tests ----------------
+
+// RUN: %clang -E -dM %s -o - 2>&1 \
+// RUN:     --target=wasm32-unknown-unknown \
+// RUN:   | FileCheck -match-full-lines %s -check-prefix=CHECK_WASM_ATOMICS
+// RUN: %clang -E -dM %s -o - 2>&1 \
+// RUN:     --target=wasm64-unknown-unknown \
+// RUN:   | FileCheck -match-full-lines %s -check-prefix=CHECK_WASM_ATOMICS
+
+// CHECK_WASM_ATOMICS: #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_1 1
+// 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