diff --git a/CMakeLists.txt b/CMakeLists.txt
index 3babb3846d..1b83cbf6b5 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -221,16 +221,19 @@ endmacro()
 option(MY_ASSEMBLER_IS_TOO_OLD_FOR_AVX "Exclude AVX code from the build" OFF)
 if(MY_ASSEMBLER_IS_TOO_OLD_FOR_AVX)
   add_definitions(-DMY_ASSEMBLER_IS_TOO_OLD_FOR_AVX)
-  add_definitions(-DMY_ASSEMBLER_IS_TOO_OLD_FOR_AVX512)
+  add_definitions(-DMY_ASSEMBLER_IS_TOO_OLD_FOR_512AVX)
   message(STATUS "MY_ASSEMBLER_IS_TOO_OLD_FOR_AVX selected, removing AVX optimisations")
 endif()
 
 # Some assemblers know about AVX but not AVX512 instructions, e.g. gcc 4.8.2.
 # This flag can be set to handle such cases.
-option(MY_ASSEMBLER_IS_TOO_OLD_FOR_AVX512 "Exclude AVX512 code from the build" OFF)
-if(MY_ASSEMBLER_IS_TOO_OLD_FOR_AVX512)
-  add_definitions(-DMY_ASSEMBLER_IS_TOO_OLD_FOR_AVX512)
-  message(STATUS "MY_ASSEMBLER_IS_TOO_OLD_FOR_AVX512 selected, removing AVX512 optimisations")
+# Note that the flag's name has "512AVX" instead of "AVX512" so that it doesn't
+# include the entire flag -DMY_ASSEMBLER_IS_TOO_OLD_FOR_AVX and match it
+# in the Perl files checks.
+option(MY_ASSEMBLER_IS_TOO_OLD_FOR_512AVX "Exclude AVX512 code from the build" OFF)
+if(MY_ASSEMBLER_IS_TOO_OLD_FOR_512AVX)
+  add_definitions(-DMY_ASSEMBLER_IS_TOO_OLD_FOR_512AVX)
+  message(STATUS "MY_ASSEMBLER_IS_TOO_OLD_FOR_512AVX selected, removing AVX512 optimisations")
 endif()
 
 # Detect if memcmp is wrongly stripped like strcmp.
diff --git a/crypto/CMakeLists.txt b/crypto/CMakeLists.txt
index 83ba16f700..1c64967d71 100644
--- a/crypto/CMakeLists.txt
+++ b/crypto/CMakeLists.txt
@@ -79,8 +79,8 @@ if(PERL_EXECUTABLE)
       set(PERLASM_FLAGS "${PERLASM_FLAGS} -DMY_ASSEMBLER_IS_TOO_OLD_FOR_AVX")
     endif()
 
-    if(MY_ASSEMBLER_IS_TOO_OLD_FOR_AVX512)
-      set(PERLASM_FLAGS "${PERLASM_FLAGS} -DMY_ASSEMBLER_IS_TOO_OLD_FOR_AVX512")
+    if(MY_ASSEMBLER_IS_TOO_OLD_FOR_512AVX)
+      set(PERLASM_FLAGS "${PERLASM_FLAGS} -DMY_ASSEMBLER_IS_TOO_OLD_FOR_512AVX")
     endif()
 
     add_custom_command(
diff --git a/crypto/fipsmodule/modes/asm/aesni-gcm-avx512.pl b/crypto/fipsmodule/modes/asm/aesni-gcm-avx512.pl
index 47f54e9c7a..ba69fb6081 100644
--- a/crypto/fipsmodule/modes/asm/aesni-gcm-avx512.pl
+++ b/crypto/fipsmodule/modes/asm/aesni-gcm-avx512.pl
@@ -49,7 +49,7 @@
 
 $avx512vaes = 1;
 for (@ARGV) { $avx512vaes = 0 if
-   (/-DMY_ASSEMBLER_IS_TOO_OLD_FOR_AVX512/); }
+   (/-DMY_ASSEMBLER_IS_TOO_OLD_FOR_512AVX/); }
 
 # TODO(awslc, CryptoAlg-1701): fix the script to generate assembly that
 # can be handled by MSVC2015 linker. Currently, the linker chokes on
diff --git a/crypto/fipsmodule/modes/gcm.c b/crypto/fipsmodule/modes/gcm.c
index 5e3d4e03d1..e454859a3c 100644
--- a/crypto/fipsmodule/modes/gcm.c
+++ b/crypto/fipsmodule/modes/gcm.c
@@ -797,7 +797,7 @@ int crypto_gcm_clmul_enabled(void) {
 int crypto_gcm_avx512_enabled(void) {
 #if defined(GHASH_ASM_X86_64) && \
     !defined(OPENSSL_WINDOWS) && \
-    !defined(MY_ASSEMBLER_IS_TOO_OLD_FOR_AVX512)
+    !defined(MY_ASSEMBLER_IS_TOO_OLD_FOR_512AVX)
     // TODO(awslc): remove the Windows guard once CryptoAlg-1701 is resolved.
   return (CRYPTO_is_VAES_capable() &&
           CRYPTO_is_AVX512_capable() &&
diff --git a/crypto/fipsmodule/modes/gcm_test.cc b/crypto/fipsmodule/modes/gcm_test.cc
index d0ffbd2ec0..2e82abfeea 100644
--- a/crypto/fipsmodule/modes/gcm_test.cc
+++ b/crypto/fipsmodule/modes/gcm_test.cc
@@ -189,7 +189,7 @@ TEST(GCMTest, ABI) {
         }
       }
     }
-#if !defined(MY_ASSEMBLER_IS_TOO_OLD_FOR_AVX512)
+#if !defined(MY_ASSEMBLER_IS_TOO_OLD_FOR_512AVX)
     if (crypto_gcm_avx512_enabled()) {
       CHECK_ABI_SEH(gcm_init_avx512, Htable, kH);
       CHECK_ABI_SEH(gcm_gmult_avx512, X, Htable);
@@ -224,7 +224,7 @@ TEST(GCMTest, ABI) {
         }
       }
     }
-#endif // !MY_ASSEMBLER_IS_TOO_OLD_FOR_AVX512)
+#endif // !MY_ASSEMBLER_IS_TOO_OLD_FOR_512AVX)
 #endif  // GHASH_ASM_X86_64
   }
 #endif  // GHASH_ASM_X86 || GHASH_ASM_X86_64
diff --git a/crypto/impl_dispatch_test.cc b/crypto/impl_dispatch_test.cc
index ef4cfb8b47..e7d1365308 100644
--- a/crypto/impl_dispatch_test.cc
+++ b/crypto/impl_dispatch_test.cc
@@ -56,11 +56,11 @@ class ImplDispatchTest : public ::testing::Test {
         false;
 #endif // MY_ASSEMBLER_IS_TOO_OLD_FOR_AVX
     is_assembler_too_old_avx512 =
-#if defined(MY_ASSEMBLER_IS_TOO_OLD_FOR_AVX512)
+#if defined(MY_ASSEMBLER_IS_TOO_OLD_FOR_512AVX)
         true;
 #else
         false;
-#endif // MY_ASSEMBLER_IS_TOO_OLD_FOR_AVX512
+#endif // MY_ASSEMBLER_IS_TOO_OLD_FOR_512AVX
 #endif  // X86 || X86_64
   }
 
diff --git a/tests/ci/run_posix_tests.sh b/tests/ci/run_posix_tests.sh
index ac5bcbc535..0ac68291f9 100755
--- a/tests/ci/run_posix_tests.sh
+++ b/tests/ci/run_posix_tests.sh
@@ -47,7 +47,7 @@ for build_option in "${build_options_to_test[@]}"; do
   run_build ${build_option} -DMY_ASSEMBLER_IS_TOO_OLD_FOR_AVX=ON
 done
 
-## Build option: MY_ASSEMBLER_IS_TOO_OLD_FOR_AVX512
+## Build option: MY_ASSEMBLER_IS_TOO_OLD_FOR_512AVX
 for build_option in "${build_options_to_test[@]}"; do
-  run_build ${build_option} -DMY_ASSEMBLER_IS_TOO_OLD_FOR_AVX512=ON
+  run_build ${build_option} -DMY_ASSEMBLER_IS_TOO_OLD_FOR_512AVX=ON
 done