Fix gcc build

CMakeLists.txt

@@ -49,11 +49,20 @@ target_include_directories(mytest PRIVATE include)
 target_link_libraries(mytest PRIVATE doctest nanobench simdjson)
 doctest_discover_tests(mytest)
 
-add_executable(fuzz src/fuzz.cpp)
-target_include_directories(fuzz PRIVATE include)
-target_link_libraries(fuzz PRIVATE simdjson)
-target_compile_options(fuzz PRIVATE -fsanitize=fuzzer)
-target_link_options(fuzz PRIVATE -fsanitize=fuzzer)
+include(CMakePushCheckState)
+include(CheckCXXCompilerFlag)
+cmake_push_check_state()
+set(CMAKE_REQUIRED_LINK_OPTIONS -fsanitize=fuzzer-no-link)
+check_cxx_compiler_flag(-fsanitize=fuzzer-no-link HAS_LIB_FUZZER)
+cmake_pop_check_state()
+
+if(HAS_LIB_FUZZER)
+  add_executable(fuzz src/fuzz.cpp)
+  target_include_directories(fuzz PRIVATE include)
+  target_link_libraries(fuzz PRIVATE simdjson)
+  target_compile_options(fuzz PRIVATE -fsanitize=fuzzer)
+  target_link_options(fuzz PRIVATE -fsanitize=fuzzer)
+endif()
 
 add_executable(validate src/validate.cpp)
 target_include_directories(validate PRIVATE include)

src/parser3.h

@@ -414,7 +414,7 @@ inline WeaselJsonStatus n_string2(Parser3 *self) {
       }
       break;
     }
-    __m128 x;
+    __m128i x;
     memcpy(&x, self->buf, 16);
     const uint32_t dubquote =
         _mm_movemask_epi8(_mm_cmpeq_epi8(_mm_set1_epi8('"'), x));
@@ -493,6 +493,8 @@ inline WeaselJsonStatus n_string2(Parser3 *self) {
   case Tables::CONTINUATION_BYTE:
   case Tables::INVALID:
     [[unlikely]] return WeaselJson_REJECT;
+  default:
+    __builtin_unreachable();
   }
 }
 
@@ -1085,6 +1087,8 @@ inline WeaselJsonStatus Parser3::keepGoing(Parser3 *self) {
       case T_EOF:
       case N_SYMBOL_COUNT:
         break;
+      default:
+        __builtin_unreachable();
       }
       return WeaselJson_AGAIN;
     }