diff --git a/libc/fuzzing/stdlib/atof_differential_fuzz.cpp b/libc/fuzzing/stdlib/atof_differential_fuzz.cpp
--- a/libc/fuzzing/stdlib/atof_differential_fuzz.cpp
+++ b/libc/fuzzing/stdlib/atof_differential_fuzz.cpp
@@ -37,7 +37,9 @@
 }
 
 bool should_be_skipped(const uint8_t *str) {
-  double init_result = ::atof(reinterpret_cast<const char *>(str));
+  // We can be more confident that our atof is correct than the system one, at
+  // least for this case.
+  double init_result = __llvm_libc::atof(reinterpret_cast<const char *>(str));
   if (init_result < 0) {
     init_result = -init_result;
   }