diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 6459c7581569..a937a52aa92c 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,14 @@
+2008-07-03  Paolo Carlini  <paolo.carlini@oracle.com>
+
+	* testsuite/21_strings/basic_string/numeric_conversions/char/stof.cc:
+	Improve check on long double limits.
+	* testsuite/21_strings/basic_string/numeric_conversions/char/stod.cc:
+	Likewise.
+	* testsuite/21_strings/basic_string/numeric_conversions/wchar_t/
+	stof.cc: Likewise.
+	* testsuite/21_strings/basic_string/numeric_conversions/wchar_t/
+	stod.cc: Likewise.
+
 2008-07-03  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	* libsupc++/Makefile.am: Add initializer_list to the headers.
diff --git a/libstdc++-v3/testsuite/21_strings/basic_string/numeric_conversions/char/stod.cc b/libstdc++-v3/testsuite/21_strings/basic_string/numeric_conversions/char/stod.cc
index f26a865684d2..765c5a210ec5 100644
--- a/libstdc++-v3/testsuite/21_strings/basic_string/numeric_conversions/char/stod.cc
+++ b/libstdc++-v3/testsuite/21_strings/basic_string/numeric_conversions/char/stod.cc
@@ -107,7 +107,8 @@ test01()
     }
   VERIFY( test );
 
-  if (sizeof(double) < sizeof(long double))
+  if ((numeric_limits<long double>::max() / 10000.0L)
+      > numeric_limits<double>::max())
     {
       test = false;
       d1 = -1.0;
diff --git a/libstdc++-v3/testsuite/21_strings/basic_string/numeric_conversions/char/stof.cc b/libstdc++-v3/testsuite/21_strings/basic_string/numeric_conversions/char/stof.cc
index 515769e18f76..5645c0af9b8f 100644
--- a/libstdc++-v3/testsuite/21_strings/basic_string/numeric_conversions/char/stof.cc
+++ b/libstdc++-v3/testsuite/21_strings/basic_string/numeric_conversions/char/stof.cc
@@ -107,7 +107,8 @@ test01()
     }
   VERIFY( test );
 
-  if (sizeof(float) < sizeof(long double))
+  if ((numeric_limits<long double>::max() / 10000.0L)
+      > numeric_limits<float>::max())
     {
       test = false;
       f1 = -1.0f;
diff --git a/libstdc++-v3/testsuite/21_strings/basic_string/numeric_conversions/wchar_t/stod.cc b/libstdc++-v3/testsuite/21_strings/basic_string/numeric_conversions/wchar_t/stod.cc
index c1ebbb228d9b..e494f4282baf 100644
--- a/libstdc++-v3/testsuite/21_strings/basic_string/numeric_conversions/wchar_t/stod.cc
+++ b/libstdc++-v3/testsuite/21_strings/basic_string/numeric_conversions/wchar_t/stod.cc
@@ -107,7 +107,8 @@ test01()
     }
   VERIFY( test );
 
-  if (sizeof(double) < sizeof(long double))
+  if ((numeric_limits<long double>::max() / 10000.0L)
+      > numeric_limits<double>::max())
     {
       test = false;
       d1 = -1.0;
diff --git a/libstdc++-v3/testsuite/21_strings/basic_string/numeric_conversions/wchar_t/stof.cc b/libstdc++-v3/testsuite/21_strings/basic_string/numeric_conversions/wchar_t/stof.cc
index 6f443c8bf973..a6319f8e31e5 100644
--- a/libstdc++-v3/testsuite/21_strings/basic_string/numeric_conversions/wchar_t/stof.cc
+++ b/libstdc++-v3/testsuite/21_strings/basic_string/numeric_conversions/wchar_t/stof.cc
@@ -107,7 +107,8 @@ test01()
     }
   VERIFY( test );
 
-  if (sizeof(float) < sizeof(long double))
+  if ((numeric_limits<long double>::max() / 10000.0L)
+      > numeric_limits<float>::max())
     {
       test = false;
       f1 = -1.0f;