c: C2x binary constants

C2x adds binary integer constants (approved at the last WG14 meeting,
though not yet added to the working draft in git).  Configure libcpp
to consider these a standard feature in C2x mode, with appropriate
updates to diagnostics including support for diagnosing them with
-std=c2x -Wc11-c2x-compat.

Bootstrapped with no regressions for x86_64-pc-linux-gnu.

gcc/testsuite/
2020-11-13  Joseph Myers  <joseph@codesourcery.com>

	* gcc.dg/binary-constants-2.c, gcc.dg/binary-constants-3.c,
	gcc.dg/system-binary-constants-1.c: Update expected diagnostics.
	* gcc.dg/c11-binary-constants-1.c,
	gcc.dg/c11-binary-constants-2.c, gcc.dg/c2x-binary-constants-1.c,
	gcc.dg/c2x-binary-constants-2.c, gcc.dg/c2x-binary-constants-3.c:
	New tests.

libcpp/
2020-11-13  Joseph Myers  <joseph@codesourcery.com>

	* expr.c (cpp_classify_number): Update diagnostic for binary
	constants for C.  Also diagnose binary constants for
	-Wc11-c2x-compat.
	* init.c (lang_defaults): Enable binary constants for GNUC2X and
	STDC2X.

8 files changed, 52 insertions, 5 deletions

diff --git a/gcc/testsuite/gcc.dg/binary-constants-2.c b/gcc/testsuite/gcc.dg/binary-constants-2.c
index 6c3928a..5339d57 100644
--- a/gcc/testsuite/gcc.dg/binary-constants-2.c
+++ b/gcc/testsuite/gcc.dg/binary-constants-2.c
@@ -9,8 +9,8 @@
 int
 foo (void)
 {
-#if FOO /* { dg-warning "binary constants are a GCC extension" } */
+#if FOO /* { dg-warning "binary constants are a C2X feature or GCC extension" } */
   return 23;
 #endif
-  return 0b1101; /* { dg-warning "binary constants are a GCC extension" } */
+  return 0b1101; /* { dg-warning "binary constants are a C2X feature or GCC extension" } */
 }
diff --git a/gcc/testsuite/gcc.dg/binary-constants-3.c b/gcc/testsuite/gcc.dg/binary-constants-3.c
index 410fc4c..5b49cb4 100644
--- a/gcc/testsuite/gcc.dg/binary-constants-3.c
+++ b/gcc/testsuite/gcc.dg/binary-constants-3.c
@@ -9,8 +9,8 @@
 int
 foo (void)
 {
-#if FOO /* { dg-error "binary constants are a GCC extension" } */
+#if FOO /* { dg-error "binary constants are a C2X feature or GCC extension" } */
   return 23;
 #endif
-  return 0b1101; /* { dg-error "binary constants are a GCC extension" } */
+  return 0b1101; /* { dg-error "binary constants are a C2X feature or GCC extension" } */
 }
diff --git a/gcc/testsuite/gcc.dg/c11-binary-constants-1.c b/gcc/testsuite/gcc.dg/c11-binary-constants-1.c
new file mode 100644
index 0000000..fdc7df4
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/c11-binary-constants-1.c
@@ -0,0 +1,11 @@
+/* Test that binary constants are diagnosed in C11 mode: -pedantic.  */
+/* { dg-do compile } */
+/* { dg-options "-std=c11 -pedantic" } */
+
+int a = 0b1; /* { dg-warning "binary constants" } */
+#if 0b101 /* { dg-warning "binary constants" } */
+#endif
+
+int b = 0B1; /* { dg-warning "binary constants" } */
+#if 0B101 /* { dg-warning "binary constants" } */
+#endif
diff --git a/gcc/testsuite/gcc.dg/c11-binary-constants-2.c b/gcc/testsuite/gcc.dg/c11-binary-constants-2.c
new file mode 100644
index 0000000..6b48a5d
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/c11-binary-constants-2.c
@@ -0,0 +1,11 @@
+/* Test that binary constants are diagnosed in C11 mode: -pedantic-errors.  */
+/* { dg-do compile } */
+/* { dg-options "-std=c11 -pedantic-errors" } */
+
+int a = 0b1; /* { dg-error "binary constants" } */
+#if 0b101 /* { dg-error "binary constants" } */
+#endif
+
+int b = 0B1; /* { dg-error "binary constants" } */
+#if 0B101 /* { dg-error "binary constants" } */
+#endif
diff --git a/gcc/testsuite/gcc.dg/c2x-binary-constants-1.c b/gcc/testsuite/gcc.dg/c2x-binary-constants-1.c
new file mode 100644
index 0000000..bbb2bc8
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/c2x-binary-constants-1.c
@@ -0,0 +1,5 @@
+/* Test C2x binary constants.  Valid syntax and types.  */
+/* { dg-do compile } */
+/* { dg-options "-std=c2x -pedantic-errors" } */
+
+#include "binary-constants-1.c"
diff --git a/gcc/testsuite/gcc.dg/c2x-binary-constants-2.c b/gcc/testsuite/gcc.dg/c2x-binary-constants-2.c
new file mode 100644
index 0000000..4379427
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/c2x-binary-constants-2.c
@@ -0,0 +1,11 @@
+/* Test that binary constants are accepted in C2X mode: compat warnings.  */
+/* { dg-do compile } */
+/* { dg-options "-std=c2x -Wc11-c2x-compat" } */
+
+int a = 0b1; /* { dg-warning "C2X feature" } */
+#if 0b101 /* { dg-warning "C2X feature" } */
+#endif
+
+int b = 0B1; /* { dg-warning "C2X feature" } */
+#if 0B101 /* { dg-warning "C2X feature" } */
+#endif
diff --git a/gcc/testsuite/gcc.dg/c2x-binary-constants-3.c b/gcc/testsuite/gcc.dg/c2x-binary-constants-3.c
new file mode 100644
index 0000000..7604791f
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/c2x-binary-constants-3.c
@@ -0,0 +1,9 @@
+/* Test C2x binary constants.  Invalid constants.  */
+/* { dg-do compile } */
+/* { dg-options "-std=c2x -pedantic-errors" } */
+
+int a = 0b; /* { dg-error "invalid suffix" } */
+int b = 0B2; /* { dg-error "invalid suffix" } */
+int c = 0B02; /* { dg-error "invalid digit" } */
+int d = 0b1.1; /* { dg-error "invalid prefix" } */
+int e = 0B0p0; /* { dg-error "invalid suffix" } */
diff --git a/gcc/testsuite/gcc.dg/system-binary-constants-1.c b/gcc/testsuite/gcc.dg/system-binary-constants-1.c
index 921ee20..ca16215 100644
--- a/gcc/testsuite/gcc.dg/system-binary-constants-1.c
+++ b/gcc/testsuite/gcc.dg/system-binary-constants-1.c
@@ -14,5 +14,5 @@ foo (void)
 					    warning.  */
   return 23;
 #endif
-  return 0b1101; /* { dg-warning "binary constants are a GCC extension" } */
+  return 0b1101; /* { dg-warning "binary constants are a C2X feature or GCC extension" } */
 }