diff --git a/src/config/CMakeLists.txt b/src/config/CMakeLists.txt
--- a/src/config/CMakeLists.txt
+++ b/src/config/CMakeLists.txt
@@ -55,15 +55,15 @@
 check_include_files("sys/select.h" HAVE_SYS_SELECT_H)
 check_include_files("sys/prctl.h" HAVE_SYS_PRCTL_H)
 
-# Bitmanip intrinsics
-function(check_builtin_exist SYMBOL VARIABLE)
+# Built-in compiler intrinsics
+function(check_builtin_exist_with_code SYMBOL VARIABLE CODE)
 	set(
 		SOURCE_FILE
 		"${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeTmp/CheckBuiltinExists.c"
 	)
 	set(
 		CMAKE_CONFIGURABLE_FILE_CONTENT
-		"int main(int argc, char** argv) { (void)argv; return ${SYMBOL}(argc); }\n"
+		"int main(int argc, char** argv) { (void)argv; return ${CODE}; }\n"
 	)
 	configure_file(
 		"${CMAKE_ROOT}/Modules/CMakeConfigurableFile.in"
@@ -101,10 +101,26 @@
 	endif()
 endfunction()
 
+function(check_builtin_exist SYMBOL VARIABLE)
+	check_builtin_exist_with_code(
+		${SYMBOL}
+		${VARIABLE}
+		"${SYMBOL}(argc)"
+	)
+endfunction()
+
+# Bitmanip intrinsics
 check_builtin_exist(__builtin_clz HAVE_DECL___BUILTIN_CLZ)
 check_builtin_exist(__builtin_clzl HAVE_DECL___BUILTIN_CLZL)
 check_builtin_exist(__builtin_clzll HAVE_DECL___BUILTIN_CLZLL)
 check_builtin_exist(__builtin_popcount HAVE_DECL___BUILTIN_POPCOUNT)
+# Overflow math
+check_builtin_exist_with_code(
+	__builtin_saddll_overflow HAVE_DECL___BUILTIN_SADDLL_OVERFLOW
+	"__builtin_saddll_overflow(argc, argc, (long long int*)&argc)")
+check_builtin_exist_with_code(
+	__builtin_ssubll_overflow HAVE_DECL___BUILTIN_SSUBLL_OVERFLOW
+	"__builtin_ssubll_overflow(argc, argc, (long long int*)&argc)")
 
 # Memory management capabilities
 check_symbol_exists(M_ARENA_MAX "malloc.h" HAVE_MALLOPT_ARENA_MAX)
diff --git a/src/config/bitcoin-config.h.cmake.in b/src/config/bitcoin-config.h.cmake.in
--- a/src/config/bitcoin-config.h.cmake.in
+++ b/src/config/bitcoin-config.h.cmake.in
@@ -41,6 +41,8 @@
 #cmakedefine HAVE_DECL___BUILTIN_CLZL 1
 #cmakedefine HAVE_DECL___BUILTIN_CLZLL 1
 #cmakedefine HAVE_DECL___BUILTIN_POPCOUNT 1
+#cmakedefine HAVE_DECL___BUILTIN_SADDLL_OVERFLOW 1
+#cmakedefine HAVE_DECL___BUILTIN_SSUBLL_OVERFLOW 1
 
 #cmakedefine HAVE_MALLOPT_ARENA_MAX 1
 #cmakedefine HAVE_MALLOC_INFO 1
diff --git a/src/script/intmath.h b/src/script/intmath.h
--- a/src/script/intmath.h
+++ b/src/script/intmath.h
@@ -7,6 +7,11 @@
 #include <cstdlib>
 #include <limits>
 
+static_assert(std::numeric_limits<long long int>::max() ==
+              std::numeric_limits<int64_t>::max());
+static_assert(std::numeric_limits<long long int>::min() ==
+              std::numeric_limits<int64_t>::min());
+
 /**
  * Computes a + b and stores it in result. If the sum overflows or results in an
  * invalid 63+sign-bit integer, return true, otherwise false. Overflow checks
@@ -25,6 +30,23 @@
     return result == std::numeric_limits<int64_t>::min();
 }
 
+/**
+ * Computes a + b and stores it in result. If the sum overflows or results in an
+ * invalid 63+sign-bit integer, return true, otherwise false.
+ * Uses built-in overflow functions if available, and emulated overflow math
+ * otherwise.
+ */
+static bool AddInt63Overflow(int64_t a, int64_t b, int64_t &result) {
+#if HAVE_DECL___BUILTIN_SADDLL_OVERFLOW
+    if (__builtin_saddll_overflow(a, b, (long long int *)&result)) {
+        return true;
+    }
+    return result == std::numeric_limits<int64_t>::min();
+#else
+    return AddInt63OverflowEmulated(a, b, result);
+#endif
+}
+
 /**
  * Computes a - b and stores it in result. If the difference overflows or
  * results in an invalid 63+sign-bit integer, return true, otherwise false.
@@ -43,4 +65,21 @@
     return result == std::numeric_limits<int64_t>::min();
 }
 
+/**
+ * Computes a - b and stores it in result. If the sum difference or results in
+ * an invalid 63+sign-bit integer, return true, otherwise false.
+ * Uses built-in overflow functions if available, and emulated overflow math
+ * otherwise.
+ */
+static bool SubInt63Overflow(int64_t a, int64_t b, int64_t &result) {
+#if HAVE_DECL___BUILTIN_SSUBLL_OVERFLOW
+    if (__builtin_ssubll_overflow(a, b, (long long int *)&result)) {
+        return true;
+    }
+    return result == std::numeric_limits<int64_t>::min();
+#else
+    return SubInt63OverflowEmulated(a, b, result);
+#endif
+}
+
 #endif // BITCOIN_SCRIPT_INTMATH_H
diff --git a/src/test/intmath_tests.cpp b/src/test/intmath_tests.cpp
--- a/src/test/intmath_tests.cpp
+++ b/src/test/intmath_tests.cpp
@@ -110,6 +110,34 @@
             BOOST_CHECK_EQUAL(result, a - b);
         }
     }
+    {
+        // Test AddInt63Overflow
+        int64_t result;
+        bool expect_overflow = !IsInScriptBounds(a + b);
+        bool had_overflow = AddInt63Overflow(a_64, b_64, result);
+        if (expect_overflow) {
+            BOOST_CHECK_MESSAGE(
+                had_overflow, strprintf("%d + %d didn't overflow", a_64, b_64));
+        } else {
+            BOOST_CHECK_MESSAGE(!had_overflow,
+                                strprintf("%d + %d overflowed", a_64, b_64));
+            BOOST_CHECK_EQUAL(result, a + b);
+        }
+    }
+    {
+        // Test SubInt63Overflow
+        int64_t result;
+        bool expect_overflow = !IsInScriptBounds(a - b);
+        bool had_overflow = SubInt63Overflow(a_64, b_64, result);
+        if (expect_overflow) {
+            BOOST_CHECK_MESSAGE(
+                had_overflow, strprintf("%d - %d didn't overflow", a_64, b_64));
+        } else {
+            BOOST_CHECK_MESSAGE(!had_overflow,
+                                strprintf("%d - %d overflowed", a_64, b_64));
+            BOOST_CHECK_EQUAL(result, a - b);
+        }
+    }
 }
 
 /** Generate random number in [-2^63; 2^63]. */