diff --git a/gcc/testsuite/gcc.dg/cpp/normalize-3.c b/gcc/testsuite/c-c++-common/cpp/normalize-3.c
similarity index 88%
rename from gcc/testsuite/gcc.dg/cpp/normalize-3.c
rename to gcc/testsuite/c-c++-common/cpp/normalize-3.c
index a4f496fbb3a..ae0184cfbb0 100644
--- a/gcc/testsuite/gcc.dg/cpp/normalize-3.c
+++ b/gcc/testsuite/c-c++-common/cpp/normalize-3.c
@@ -1,5 +1,6 @@
 /* { dg-do preprocess } */
-/* { dg-options "-std=c99 -fextended-identifiers -Wnormalized=id" } */
+/* { dg-options "-std=c99 -fextended-identifiers -Wnormalized=id" { target c } } */
+/* { dg-options "-fextended-identifiers -Wnormalized=id" { target c++ } } */
 
 \u00AA
 \u00B7
diff --git a/gcc/testsuite/c-c++-common/cpp/warning-directive-1.c b/gcc/testsuite/c-c++-common/cpp/warning-directive-1.c
new file mode 100644
index 00000000000..e23d240c2f7
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/cpp/warning-directive-1.c
@@ -0,0 +1,4 @@
+// { dg-do preprocess }
+// { dg-options "-std=gnu99 -fdiagnostics-show-option" { target c } }
+// { dg-options "-fdiagnostics-show-option" { target c++ } }
+#warning "Printed"  // { dg-warning "\"Printed\" .-Wcpp." }
diff --git a/gcc/testsuite/gcc.dg/cpp/warning-directive-2.c b/gcc/testsuite/c-c++-common/cpp/warning-directive-2.c
similarity index 71%
rename from gcc/testsuite/gcc.dg/cpp/warning-directive-2.c
rename to gcc/testsuite/c-c++-common/cpp/warning-directive-2.c
index 753b84a692e..15c74d2baa4 100644
--- a/gcc/testsuite/gcc.dg/cpp/warning-directive-2.c
+++ b/gcc/testsuite/c-c++-common/cpp/warning-directive-2.c
@@ -1,4 +1,5 @@
 // { dg-do preprocess }
-// { dg-options "-std=gnu99 -fdiagnostics-show-option -Werror=cpp" }
+// { dg-options "-std=gnu99 -fdiagnostics-show-option -Werror=cpp" { target c } }
+// { dg-options "-fdiagnostics-show-option -Werror=cpp" { target c++ } }
 /* { dg-message "some warnings being treated as errors" "" {target "*-*-*"} 0 } */
 #warning "Printed"  // { dg-error "\"Printed\" .-Wcpp." }
diff --git a/gcc/testsuite/gcc.dg/cpp/warning-directive-3.c b/gcc/testsuite/c-c++-common/cpp/warning-directive-3.c
similarity index 56%
rename from gcc/testsuite/gcc.dg/cpp/warning-directive-3.c
rename to gcc/testsuite/c-c++-common/cpp/warning-directive-3.c
index 48c97f3ac5b..0c50a318df6 100644
--- a/gcc/testsuite/gcc.dg/cpp/warning-directive-3.c
+++ b/gcc/testsuite/c-c++-common/cpp/warning-directive-3.c
@@ -1,4 +1,4 @@
 // { dg-do preprocess }
-// { dg-options "-std=gnu99 -fdiagnostics-show-option -Werror -Wno-error=cpp" }
-
+// { dg-options "-std=gnu99 -fdiagnostics-show-option -Werror -Wno-error=cpp" { target c } }
+// { dg-options "-fdiagnostics-show-option -Werror -Wno-error=cpp" { target c++ } }
 #warning "Printed"  // { dg-warning "\"Printed\" .-Wcpp." }
diff --git a/gcc/testsuite/gcc.dg/cpp/warning-directive-4.c b/gcc/testsuite/c-c++-common/cpp/warning-directive-4.c
similarity index 60%
rename from gcc/testsuite/gcc.dg/cpp/warning-directive-4.c
rename to gcc/testsuite/c-c++-common/cpp/warning-directive-4.c
index 2eb101765da..23069f8ade2 100644
--- a/gcc/testsuite/gcc.dg/cpp/warning-directive-4.c
+++ b/gcc/testsuite/c-c++-common/cpp/warning-directive-4.c
@@ -1,4 +1,4 @@
 // { dg-do preprocess }
-// { dg-options "-std=gnu99 -fdiagnostics-show-option -Wno-cpp" }
-
+// { dg-options "-std=gnu99 -fdiagnostics-show-option -Wno-cpp" { target c } }
+// { dg-options "-fdiagnostics-show-option -Wno-cpp" { target c++ } }
 #warning "Not printed"  // { dg-bogus "." }
diff --git a/gcc/testsuite/g++.dg/cpp/normalize-1.C b/gcc/testsuite/g++.dg/cpp/normalize-1.C
deleted file mode 100644
index 536a3b45b98..00000000000
--- a/gcc/testsuite/g++.dg/cpp/normalize-1.C
+++ /dev/null
@@ -1,34 +0,0 @@
-/* { dg-do preprocess } */
-/* { dg-options "-fextended-identifiers -Wnormalized=id" } */
-
-\u00AA
-\u00B7
-\u0F43  /* { dg-warning "not in NFC" } */
-a\u05B8\u05B9\u05B9\u05BBb
- a\u05BB\u05B9\u05B8\u05B9b  /* { dg-warning "not in NFC" } */
-\u09CB
-\u09C7\u09BE /* { dg-warning "not in NFC" } */
-\u0B4B
-\u0B47\u0B3E /* { dg-warning "not in NFC" } */
-\u0BCA
-\u0BC6\u0BBE /* { dg-warning "not in NFC" } */
-\u0BCB
-\u0BC7\u0BBE /* { dg-warning "not in NFC" } */
-\u0CCA
-\u0CC6\u0CC2 /* { dg-warning "not in NFC" } */
-\u0D4A
-\u0D46\u0D3E /* { dg-warning "not in NFC" } */
-\u0D4B
-\u0D47\u0D3E /* { dg-warning "not in NFC" } */
-
-K
-\u212A
-
-\u03AC
-\u1F71 /* { dg-warning "not in NFC" } */
-
-\uAC00
-\u1100\u1161
-\uAC01
-\u1100\u1161\u11A8
-\uAC00\u11A8
diff --git a/gcc/testsuite/g++.dg/cpp/warning-directive-1.C b/gcc/testsuite/g++.dg/cpp/warning-directive-1.C
deleted file mode 100644
index 1ce18c6e2c6..00000000000
--- a/gcc/testsuite/g++.dg/cpp/warning-directive-1.C
+++ /dev/null
@@ -1,4 +0,0 @@
-// { dg-do preprocess }
-// { dg-options "-fdiagnostics-show-option" }
-
-#warning "Printed"  // { dg-warning "\"Printed\" .-Wcpp." }
diff --git a/gcc/testsuite/g++.dg/cpp/warning-directive-2.C b/gcc/testsuite/g++.dg/cpp/warning-directive-2.C
deleted file mode 100644
index c2efc172abe..00000000000
--- a/gcc/testsuite/g++.dg/cpp/warning-directive-2.C
+++ /dev/null
@@ -1,4 +0,0 @@
-// { dg-do preprocess }
-// { dg-options "-fdiagnostics-show-option -Werror=cpp" }
-/* { dg-message "some warnings being treated as errors" "" {target "*-*-*"} 0 } */
-#warning "Printed"  // { dg-error "\"Printed\" .-Wcpp." }
diff --git a/gcc/testsuite/g++.dg/cpp/warning-directive-3.C b/gcc/testsuite/g++.dg/cpp/warning-directive-3.C
deleted file mode 100644
index 8ed66c66f1d..00000000000
--- a/gcc/testsuite/g++.dg/cpp/warning-directive-3.C
+++ /dev/null
@@ -1,4 +0,0 @@
-// { dg-do preprocess }
-// { dg-options "-fdiagnostics-show-option -Werror -Wno-error=cpp" }
-
-#warning "Printed"  // { dg-warning "\"Printed\" .-Wcpp." }
diff --git a/gcc/testsuite/g++.dg/cpp/warning-directive-4.C b/gcc/testsuite/g++.dg/cpp/warning-directive-4.C
deleted file mode 100644
index a5db1b4d5cd..00000000000
--- a/gcc/testsuite/g++.dg/cpp/warning-directive-4.C
+++ /dev/null
@@ -1,4 +0,0 @@
-// { dg-do preprocess }
-// { dg-options "-fdiagnostics-show-option -Wno-cpp" }
-
-#warning "Not printed"  // { dg-bogus "." }
diff --git a/gcc/testsuite/g++.dg/dg.exp b/gcc/testsuite/g++.dg/dg.exp
index 2642da12301..5758218a267 100644
--- a/gcc/testsuite/g++.dg/dg.exp
+++ b/gcc/testsuite/g++.dg/dg.exp
@@ -55,5 +55,9 @@ dg-runtest $tests "" $DEFAULT_CXXFLAGS
 dg-runtest [lsort [glob -nocomplain $srcdir/c-c++-common/*.\[cSi\]]] \
 	"" ""
 
+dg-runtest [lsort [glob -nocomplain $srcdir/c-c++-common/cpp/*.\[cS\]]] \
+	"" ""
+
+
 # All done.
 dg-finish
diff --git a/gcc/testsuite/gcc.dg/cpp/cpp.exp b/gcc/testsuite/gcc.dg/cpp/cpp.exp
index acf0898407b..311223ff1f7 100644
--- a/gcc/testsuite/gcc.dg/cpp/cpp.exp
+++ b/gcc/testsuite/gcc.dg/cpp/cpp.exp
@@ -39,5 +39,10 @@ dg-init
 dg-runtest [lsort [glob -nocomplain $srcdir/$subdir/*.{c,S} ]] \
 	"" $DEFAULT_CFLAGS
 
+# C/C++ common tests.
+dg-runtest [lsort [glob -nocomplain $srcdir/c-c++-common/cpp/*.{c,S} ]] \
+	" -Wc++-compat " ""
+
+
 # All done.
 dg-finish
diff --git a/gcc/testsuite/gcc.dg/cpp/warning-directive-1.c b/gcc/testsuite/gcc.dg/cpp/warning-directive-1.c
deleted file mode 100644
index cb4bd326cc2..00000000000
--- a/gcc/testsuite/gcc.dg/cpp/warning-directive-1.c
+++ /dev/null
@@ -1,4 +0,0 @@
-// { dg-do preprocess }
-// { dg-options "-std=gnu99 -fdiagnostics-show-option" }
-
-#warning "Printed"  // { dg-warning "\"Printed\" .-Wcpp." }