diff --git a/compiler-rt/cmake/Modules/CompilerRTUtils.cmake b/compiler-rt/cmake/Modules/CompilerRTUtils.cmake
--- a/compiler-rt/cmake/Modules/CompilerRTUtils.cmake
+++ b/compiler-rt/cmake/Modules/CompilerRTUtils.cmake
@@ -579,7 +579,7 @@
   append_list_if(COMPILER_RT_HAS_RETURN_STACK_ADDRESS_FLAG -Werror=return-stack-address flags)
   append_list_if(COMPILER_RT_HAS_SIZEOF_ARRAY_DECAY_FLAG -Werror=sizeof-array-decay flags)
   append_list_if(COMPILER_RT_HAS_FORMAT_INSUFFICIENT_ARGS_FLAG -Werror=format-insufficient-args flags)
-  append_list_if(COMPILER_RT_HAS_BUILTIN_FORMAL_SECURITY_FLAG -Werror=format-security flags)
+  append_list_if(COMPILER_RT_HAS_BUILTIN_FORMAT_SECURITY_FLAG -Werror=format-security flags)
   append_list_if(COMPILER_RT_HAS_SIZEOF_ARRAY_DIV_FLAG -Werror=sizeof-array-div)
   append_list_if(COMPILER_RT_HAS_SIZEOF_POINTER_DIV_FLAG -Werror=sizeof-pointer-div)
 
diff --git a/compiler-rt/cmake/config-ix.cmake b/compiler-rt/cmake/config-ix.cmake
--- a/compiler-rt/cmake/config-ix.cmake
+++ b/compiler-rt/cmake/config-ix.cmake
@@ -113,18 +113,18 @@
 # Warnings.
 check_cxx_compiler_flag(-Wall COMPILER_RT_HAS_WALL_FLAG)
 check_cxx_compiler_flag(-Werror COMPILER_RT_HAS_WERROR_FLAG)
-check_cxx_compiler_flag("-Werror -Wframe-larger-than=512" COMPILER_RT_HAS_WFRAME_LARGER_THAN_FLAG)
-check_cxx_compiler_flag("-Werror -Wglobal-constructors"   COMPILER_RT_HAS_WGLOBAL_CONSTRUCTORS_FLAG)
-check_cxx_compiler_flag("-Werror -Wc99-extensions"     COMPILER_RT_HAS_WC99_EXTENSIONS_FLAG)
-check_cxx_compiler_flag("-Werror -Wgnu"                COMPILER_RT_HAS_WGNU_FLAG)
-check_cxx_compiler_flag("-Werror -Wnon-virtual-dtor"   COMPILER_RT_HAS_WNON_VIRTUAL_DTOR_FLAG)
-check_cxx_compiler_flag("-Werror -Wvariadic-macros"    COMPILER_RT_HAS_WVARIADIC_MACROS_FLAG)
-check_cxx_compiler_flag("-Werror -Wunused-parameter"   COMPILER_RT_HAS_WUNUSED_PARAMETER_FLAG)
-check_cxx_compiler_flag("-Werror -Wcovered-switch-default" COMPILER_RT_HAS_WCOVERED_SWITCH_DEFAULT_FLAG)
-check_cxx_compiler_flag("-Werror -Wsuggest-override"   COMPILER_RT_HAS_WSUGGEST_OVERRIDE_FLAG)
-check_cxx_compiler_flag("-Werror -Wthread-safety" COMPILER_RT_HAS_WTHREAD_SAFETY_FLAG)
-check_cxx_compiler_flag("-Werror -Wthread-safety-reference" COMPILER_RT_HAS_WTHREAD_SAFETY_REFERENCE_FLAG)
-check_cxx_compiler_flag("-Werror -Wthread-safety-beta" COMPILER_RT_HAS_WTHREAD_SAFETY_BETA_FLAG)
+check_cxx_compiler_flag(-Wframe-larger-than=512 COMPILER_RT_HAS_WFRAME_LARGER_THAN_FLAG)
+check_cxx_compiler_flag(-Wglobal-constructors COMPILER_RT_HAS_WGLOBAL_CONSTRUCTORS_FLAG)
+check_cxx_compiler_flag(-Wc99-extensions COMPILER_RT_HAS_WC99_EXTENSIONS_FLAG)
+check_cxx_compiler_flag(-Wgnu COMPILER_RT_HAS_WGNU_FLAG)
+check_cxx_compiler_flag(-Wnon-virtual-dtor COMPILER_RT_HAS_WNON_VIRTUAL_DTOR_FLAG)
+check_cxx_compiler_flag(-Wvariadic-macros COMPILER_RT_HAS_WVARIADIC_MACROS_FLAG)
+check_cxx_compiler_flag(-Wunused-parameter COMPILER_RT_HAS_WUNUSED_PARAMETER_FLAG)
+check_cxx_compiler_flag(-Wcovered-switch-default COMPILER_RT_HAS_WCOVERED_SWITCH_DEFAULT_FLAG)
+check_cxx_compiler_flag(-Wsuggest-override COMPILER_RT_HAS_WSUGGEST_OVERRIDE_FLAG)
+check_cxx_compiler_flag(-Wthread-safety COMPILER_RT_HAS_WTHREAD_SAFETY_FLAG)
+check_cxx_compiler_flag(-Wthread-safety-reference COMPILER_RT_HAS_WTHREAD_SAFETY_REFERENCE_FLAG)
+check_cxx_compiler_flag(-Wthread-safety-beta COMPILER_RT_HAS_WTHREAD_SAFETY_BETA_FLAG)
 check_cxx_compiler_flag(-Wno-pedantic COMPILER_RT_HAS_WNO_PEDANTIC)
 check_cxx_compiler_flag(-Wno-format COMPILER_RT_HAS_WNO_FORMAT)
 check_cxx_compiler_flag(-Wno-format-pedantic COMPILER_RT_HAS_WNO_FORMAT_PEDANTIC)
@@ -141,21 +141,24 @@
 check_cxx_compiler_flag(/wd4722 COMPILER_RT_HAS_WD4722_FLAG)
 check_cxx_compiler_flag(/wd4800 COMPILER_RT_HAS_WD4800_FLAG)
 
-check_cxx_compiler_flag(-Werror -Warray-bounds COMPILER_RT_HAS_ARRAY_BOUNDS_FLAG)
-check_cxx_compiler_flag(-Werror -Wuninitialized COMPILER_RT_HAS_UNINITIALIZED_FLAG)
-check_cxx_compiler_flag(-Werror -Wshadow COMPILER_RT_HAS_SHADOW_FLAG)
-check_cxx_compiler_flag(-Werror -Wempty-body COMPILER_RT_HAS_EMPTY_BODY_FLAG)
-check_cxx_compiler_flag(-Werror -Wsizeof-pointer-memaccess COMPILER_RT_HAS_SIZEOF_POINTER_MEMACCESS_FLAG)
-check_cxx_compiler_flag(-Werror -Wsizeof-array-argument COMPILER_RT_HAS_SIZEOF_ARRAY_ARGUMENT_FLAG)
-check_cxx_compiler_flag(-Werror -Wsuspicious-memaccess COMPILER_RT_HAS_SUSPICIOUS_MEMACCESS_FLAG)
-check_cxx_compiler_flag(-Werror -Wbuiltin-memcpy-chk-size COMPILER_RT_HAS_BUILTIN_MEMCPY_CHK_SIZE_FLAG)
-check_cxx_compiler_flag(-Werror -Warray-bounds-pointer-arithmetic COMPILER_RT_HAS_ARRAY_BOUNDS_POINTER_ARITHMETIC_FLAG)
-check_cxx_compiler_flag(-Werror -Wreturn-stack-address COMPILER_RT_HAS_RETURN_STACK_ADDRESS_FLAG)
-check_cxx_compiler_flag(-Werror -Wsizeof-array-decay COMPILER_RT_HAS_SIZEOF_ARRAY_DECAY_FLAG)
-check_cxx_compiler_flag(-Werror -Wformat-insufficient-args COMPILER_RT_HAS_FORMAT_INSUFFICIENT_ARGS_FLAG)
-check_cxx_compiler_flag(-Werror -Wformat-security COMPILER_RT_HAS_BUILTIN_FORMAL_SECURITY_FLAG)
-check_cxx_compiler_flag(-Werror -Wsizeof-array-div COMPILER_RT_HAS_SIZEOF_ARRAY_DIV_FLAG)
-check_cxx_compiler_flag(-Werror -Wsizeof-pointer-div COMPILER_RT_HAS_SIZEOF_POINTER_DIV_FLAG)
+check_cxx_compiler_flag(-Warray-bounds COMPILER_RT_HAS_ARRAY_BOUNDS_FLAG)
+check_cxx_compiler_flag(-Wuninitialized COMPILER_RT_HAS_UNINITIALIZED_FLAG)
+check_cxx_compiler_flag(-Wshadow COMPILER_RT_HAS_SHADOW_FLAG)
+check_cxx_compiler_flag(-Wempty-body COMPILER_RT_HAS_EMPTY_BODY_FLAG)
+check_cxx_compiler_flag(-Wsizeof-pointer-memaccess COMPILER_RT_HAS_SIZEOF_POINTER_MEMACCESS_FLAG)
+check_cxx_compiler_flag(-Wsizeof-array-argument COMPILER_RT_HAS_SIZEOF_ARRAY_ARGUMENT_FLAG)
+check_cxx_compiler_flag(-Wsuspicious-memaccess COMPILER_RT_HAS_SUSPICIOUS_MEMACCESS_FLAG)
+check_cxx_compiler_flag(-Wbuiltin-memcpy-chk-size COMPILER_RT_HAS_BUILTIN_MEMCPY_CHK_SIZE_FLAG)
+check_cxx_compiler_flag(-Warray-bounds-pointer-arithmetic COMPILER_RT_HAS_ARRAY_BOUNDS_POINTER_ARITHMETIC_FLAG)
+check_cxx_compiler_flag(-Wreturn-stack-address COMPILER_RT_HAS_RETURN_STACK_ADDRESS_FLAG)
+check_cxx_compiler_flag(-Wsizeof-array-decay COMPILER_RT_HAS_SIZEOF_ARRAY_DECAY_FLAG)
+check_cxx_compiler_flag(-Wformat-insufficient-args COMPILER_RT_HAS_FORMAT_INSUFFICIENT_ARGS_FLAG)
+check_cxx_compiler_flag(-Wsizeof-array-div COMPILER_RT_HAS_SIZEOF_ARRAY_DIV_FLAG)
+check_cxx_compiler_flag(-Wsizeof-pointer-div COMPILER_RT_HAS_SIZEOF_POINTER_DIV_FLAG)
+
+# Specifying -Wformat-security without -Wformat causes gcc to emit a warning
+# in an untypical format not recognized by CMake. Add -Werror to help it.
+check_cxx_compiler_flag("-Wformat-security -Werror" COMPILER_RT_HAS_BUILTIN_FORMAT_SECURITY_FLAG)
 
 # Symbols.
 check_symbol_exists(__func__ "" COMPILER_RT_HAS_FUNC_SYMBOL)