diff --git a/re2/testing/re2_test.cc b/re2/testing/re2_test.cc
index 5a32d92..81d5fef 100644
--- a/re2/testing/re2_test.cc
+++ b/re2/testing/re2_test.cc
@@ -879,11 +879,16 @@
     // number, since C does not guarantee to get the correctly
     // rounded answer for strtod and strtof unless the input is
     // short.
+    //
+    // This is known to fail on Cygwin and MinGW due to a broken
+    // implementation of strtof(3). Sigh.
+#if !defined(__CYGWIN__) && !defined(__MINGW32__)
     CHECK(RE2::FullMatch("0.1", "(.*)", &v));
     CHECK_EQ(v, 0.1f) << StringPrintf("%.8g != %.8g", v, 0.1f);
     CHECK(RE2::FullMatch("6700000000081920.1", "(.*)", &v));
     CHECK_EQ(v, 6700000000081920.1f)
       << StringPrintf("%.8g != %.8g", v, 6700000000081920.1f);
+#endif
   }
   {
     double v;