diff --git a/gcc/cp/constraint.cc b/gcc/cp/constraint.cc
index 3a7f968eae8..c28dad702c3 100644
--- a/gcc/cp/constraint.cc
+++ b/gcc/cp/constraint.cc
@@ -3829,6 +3829,9 @@ diagnose_trait_expr (tree expr, tree args)
     case CPTK_IS_UNION:
       inform (loc, "  %qT is not a union", t1);
       break;
+    case CPTK_IS_UNSIGNED:
+      inform (loc, "  %qT is not an unsigned type", t1);
+      break;
     case CPTK_IS_VOLATILE:
       inform (loc, "  %qT is not a volatile type", t1);
       break;
diff --git a/gcc/cp/cp-trait.def b/gcc/cp/cp-trait.def
index b2be7b7bbd7..0603b4a230f 100644
--- a/gcc/cp/cp-trait.def
+++ b/gcc/cp/cp-trait.def
@@ -94,6 +94,7 @@ DEFTRAIT_EXPR (IS_TRIVIALLY_CONSTRUCTIBLE, "__is_trivially_constructible", -1)
 DEFTRAIT_EXPR (IS_TRIVIALLY_COPYABLE, "__is_trivially_copyable", 1)
 DEFTRAIT_EXPR (IS_UNBOUNDED_ARRAY, "__is_unbounded_array", 1)
 DEFTRAIT_EXPR (IS_UNION, "__is_union", 1)
+DEFTRAIT_EXPR (IS_UNSIGNED, "__is_unsigned", 1)
 DEFTRAIT_EXPR (IS_VOLATILE, "__is_volatile", 1)
 DEFTRAIT_EXPR (REF_CONSTRUCTS_FROM_TEMPORARY, "__reference_constructs_from_temporary", 2)
 DEFTRAIT_EXPR (REF_CONVERTS_FROM_TEMPORARY, "__reference_converts_from_temporary", 2)
diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc
index deab0134509..14387821b85 100644
--- a/gcc/cp/semantics.cc
+++ b/gcc/cp/semantics.cc
@@ -12250,6 +12250,9 @@ trait_expr_value (cp_trait_kind kind, tree type1, tree type2)
     case CPTK_IS_UNION:
       return type_code1 == UNION_TYPE;
 
+    case CPTK_IS_UNSIGNED:
+      return TYPE_UNSIGNED (type1);
+
     case CPTK_IS_VOLATILE:
       return CP_TYPE_VOLATILE_P (type1);
 
@@ -12425,6 +12428,7 @@ finish_trait_expr (location_t loc, cp_trait_kind kind, tree type1, tree type2)
     case CPTK_IS_SCOPED_ENUM:
     case CPTK_IS_UNBOUNDED_ARRAY:
     case CPTK_IS_UNION:
+    case CPTK_IS_UNSIGNED:
     case CPTK_IS_VOLATILE:
       break;
 
diff --git a/gcc/testsuite/g++.dg/ext/has-builtin-1.C b/gcc/testsuite/g++.dg/ext/has-builtin-1.C
index 4bc85f4babb..3d380f94b06 100644
--- a/gcc/testsuite/g++.dg/ext/has-builtin-1.C
+++ b/gcc/testsuite/g++.dg/ext/has-builtin-1.C
@@ -164,6 +164,9 @@
 #if !__has_builtin (__is_union)
 # error "__has_builtin (__is_union) failed"
 #endif
+#if !__has_builtin (__is_unsigned)
+# error "__has_builtin (__is_unsigned) failed"
+#endif
 #if !__has_builtin (__is_volatile)
 # error "__has_builtin (__is_volatile) failed"
 #endif
diff --git a/gcc/testsuite/g++.dg/ext/is_unsigned.C b/gcc/testsuite/g++.dg/ext/is_unsigned.C
new file mode 100644
index 00000000000..2bb45d209a7
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ext/is_unsigned.C
@@ -0,0 +1,47 @@
+// { dg-do compile { target c++11 } }
+
+#include <testsuite_tr1.h>
+
+using namespace __gnu_test;
+
+#define SA(X) static_assert((X),#X)
+#define SA_TEST_CATEGORY(TRAIT, X, expect) \
+  SA(TRAIT(X) == expect);                  \
+  SA(TRAIT(const X) == expect);            \
+  SA(TRAIT(volatile X) == expect);         \
+  SA(TRAIT(const volatile X) == expect)
+
+SA_TEST_CATEGORY(__is_unsigned, void, false);
+
+SA_TEST_CATEGORY(__is_unsigned, bool, (bool(-1) > bool(0)));
+SA_TEST_CATEGORY(__is_unsigned, char, (char(-1) > char(0)));
+SA_TEST_CATEGORY(__is_unsigned, signed char, false);
+SA_TEST_CATEGORY(__is_unsigned, unsigned char, true);
+SA_TEST_CATEGORY(__is_unsigned, wchar_t, (wchar_t(-1) > wchar_t(0)));
+SA_TEST_CATEGORY(__is_unsigned, short, false);
+SA_TEST_CATEGORY(__is_unsigned, unsigned short, true);
+SA_TEST_CATEGORY(__is_unsigned, int, false);
+SA_TEST_CATEGORY(__is_unsigned, unsigned int, true);
+SA_TEST_CATEGORY(__is_unsigned, long, false);
+SA_TEST_CATEGORY(__is_unsigned, unsigned long, true);
+SA_TEST_CATEGORY(__is_unsigned, long long, false);
+SA_TEST_CATEGORY(__is_unsigned, unsigned long long, true);
+
+SA_TEST_CATEGORY(__is_unsigned, float, false);
+SA_TEST_CATEGORY(__is_unsigned, double, false);
+SA_TEST_CATEGORY(__is_unsigned, long double, false);
+
+#ifndef __STRICT_ANSI__
+// GNU Extensions.
+#ifdef __SIZEOF_INT128__
+SA_TEST_CATEGORY(__is_unsigned, unsigned __int128, true);
+SA_TEST_CATEGORY(__is_unsigned, __int128, false);
+#endif
+
+#ifdef _GLIBCXX_USE_FLOAT128
+SA_TEST_CATEGORY(__is_unsigned, __float128, false);
+#endif
+#endif
+
+// Sanity check.
+SA_TEST_CATEGORY(__is_unsigned, ClassType, false);
