diff --git a/cmake/FindLibDeflate.cmake b/cmake/FindLibDeflate.cmake
index d135edac6..0ad087386 100644
--- a/cmake/FindLibDeflate.cmake
+++ b/cmake/FindLibDeflate.cmake
@@ -26,6 +26,30 @@ if(NOT LibDeflate_FOUND)
   add_library(libdeflate STATIC ${LIBDEFLATE_SOURCES})
   sourcemeta_add_default_options(PRIVATE libdeflate)
 
+  # Check if the assembler supports ARM dot-product (udot) instructions.
+  # GCC 14+ assumes binutils is new enough, but some CI environments
+  # pair GCC 14 with older binutils that lack udot support
+  if(CMAKE_SYSTEM_PROCESSOR MATCHES "aarch64|arm64|ARM64")
+    include(CheckCSourceCompiles)
+    set(LIBDEFLATE_SAVED_CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS}")
+    set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -march=armv8.2-a+dotprod")
+    check_c_source_compiles("
+      #include <arm_neon.h>
+      int main(void) {
+        uint32x4_t a = vdupq_n_u32(0);
+        uint8x16_t b = vdupq_n_u8(0);
+        uint8x16_t c = vdupq_n_u8(0);
+        a = vdotq_u32(a, b, c);
+        return 0;
+      }
+    " LIBDEFLATE_HAS_DOTPROD_ASSEMBLER)
+    set(CMAKE_REQUIRED_FLAGS "${LIBDEFLATE_SAVED_CMAKE_REQUIRED_FLAGS}")
+    if(NOT LIBDEFLATE_HAS_DOTPROD_ASSEMBLER)
+      target_compile_definitions(libdeflate PRIVATE
+        LIBDEFLATE_ASSEMBLER_DOES_NOT_SUPPORT_DOTPROD)
+    endif()
+  endif()
+
   target_include_directories(libdeflate PUBLIC
     "$<BUILD_INTERFACE:${LIBDEFLATE_DIR}>"
     "$<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>")