c: Don't pedwarn on _FloatN{,x} or {f,F}N{,x} suffixes for C2X

Now that _Float{16,32,64,128,32x,64x,128x} and
{f,F}{16,32,64,128,32x,64x,128x} literal suffixes are in C23 standard,
I think it is undesirable to pedwarn about these for -std=c2x, so this
patch uses pedwarn_c11 instead.  In c-family/, we don't have that function
and am not sure it would be very clean to define dummy pedwarn_c11 in the
C++ FE, so the patch just does what pedwarn_c11 does using pedwarn/warning.

2023-09-06  Jakub Jelinek  <[email protected]>

gcc/c-family/
	* c-lex.cc (interpret_float): For C diagnostics on FN and FNx suffixes
	append " before C2X" to diagnostics text and follow behavior of
	pedwarn_c11.
gcc/c/
	* c-decl.cc (declspecs_add_type): Use pedwarn_c11 rather than pedwarn
	for _FloatN{,x} diagnostics and append " before C2X" to the diagnostic
	text.
gcc/testsuite/
	* gcc.dg/c11-floatn-1.c: New test.
	* gcc.dg/c11-floatn-2.c: New test.
	* gcc.dg/c11-floatn-3.c: New test.
	* gcc.dg/c11-floatn-4.c: New test.
	* gcc.dg/c11-floatn-5.c: New test.
	* gcc.dg/c11-floatn-6.c: New test.
	* gcc.dg/c11-floatn-7.c: New test.
	* gcc.dg/c11-floatn-8.c: New test.
	* gcc.dg/c2x-floatn-1.c: New test.
	* gcc.dg/c2x-floatn-2.c: New test.
	* gcc.dg/c2x-floatn-3.c: New test.
	* gcc.dg/c2x-floatn-4.c: New test.
	* gcc.dg/c2x-floatn-5.c: New test.
	* gcc.dg/c2x-floatn-6.c: New test.
	* gcc.dg/c2x-floatn-7.c: New test.
	* gcc.dg/c2x-floatn-8.c: New test.

gcc/c-family/c-lex.cc

@@ -1021,7 +1021,25 @@ interpret_float (const cpp_token *token, unsigned int flags,
 	    error ("unsupported non-standard suffix on floating constant");
 	    return error_mark_node;
 	  }
-	else if (c_dialect_cxx () && !extended)
+	else if (!c_dialect_cxx ())
+	  {
+	    if (warn_c11_c2x_compat > 0)
+	      {
+		if (pedantic && !flag_isoc2x)
+		  pedwarn (input_location, OPT_Wc11_c2x_compat,
+			   "non-standard suffix on floating constant "
+			   "before C2X");
+		else
+		  warning (OPT_Wc11_c2x_compat,
+			   "non-standard suffix on floating constant "
+			   "before C2X");
+	      }
+	    else if (warn_c11_c2x_compat != 0 && pedantic && !flag_isoc2x)
+	      pedwarn (input_location, OPT_Wpedantic,
+		       "non-standard suffix on floating constant "
+		       "before C2X");
+	  }
+	else if (!extended)
 	  {
 	    if (cxx_dialect < cxx23)
 	      pedwarn (input_location, OPT_Wpedantic,

gcc/c/c-decl.cc

@@ -12117,12 +12117,13 @@ declspecs_add_type (location_t loc, struct c_declspecs *specs,
 	    CASE_RID_FLOATN_NX:
 	      specs->floatn_nx_idx = i - RID_FLOATN_NX_FIRST;
 	      if (!in_system_header_at (input_location))
-		pedwarn (loc, OPT_Wpedantic,
-			 "ISO C does not support the %<_Float%d%s%> type",
-			 floatn_nx_types[specs->floatn_nx_idx].n,
-			 (floatn_nx_types[specs->floatn_nx_idx].extended
-			  ? "x"
-			  : ""));
+		pedwarn_c11 (loc, OPT_Wpedantic,
+			     "ISO C does not support the %<_Float%d%s%> type"
+			     " before C2X",
+			     floatn_nx_types[specs->floatn_nx_idx].n,
+			     (floatn_nx_types[specs->floatn_nx_idx].extended
+			      ? "x"
+			      : ""));
 
 	      if (specs->long_p)
 		error_at (loc,

gcc/testsuite/gcc.dg/c11-floatn-1.c

@@ -0,0 +1,21 @@
+/* { dg-do compile } */
+/* { dg-options "-std=c11 -pedantic-errors" } */
+/* { dg-add-options float32 } */
+/* { dg-add-options float64 } */
+/* { dg-add-options float32x } */
+/* { dg-require-effective-target float32 } */
+/* { dg-require-effective-target float32x } */
+/* { dg-require-effective-target float64 } */
+
+_Float32 a		/* { dg-error "ISO C does not support the '_Float32' type before C2X" } */
+  = 1.0F32;		/* { dg-error "non-standard suffix on floating constant before C2X" } */
+_Float64 b		/* { dg-error "ISO C does not support the '_Float64' type before C2X" } */
+  = 1.0F64;		/* { dg-error "non-standard suffix on floating constant before C2X" } */
+_Float32x c		/* { dg-error "ISO C does not support the '_Float32x' type before C2X" } */
+  = 1.0F32x;		/* { dg-error "non-standard suffix on floating constant before C2X" } */
+__extension__ _Float32 d
+  = 2.0F32;
+__extension__ _Float64 e
+  = 2.0F64;
+__extension__ _Float32x f
+  = 2.0F32x;

gcc/testsuite/gcc.dg/c11-floatn-2.c

@@ -0,0 +1,9 @@
+/* { dg-do compile } */
+/* { dg-options "-std=c11 -pedantic-errors" } */
+/* { dg-add-options float128 } */
+/* { dg-require-effective-target float128 } */
+
+_Float128 a		/* { dg-error "ISO C does not support the '_Float128' type before C2X" } */
+  = 1.0F128;		/* { dg-error "non-standard suffix on floating constant before C2X" } */
+__extension__ _Float128 b
+  = 2.0F128;

gcc/testsuite/gcc.dg/c11-floatn-3.c

@@ -0,0 +1,9 @@
+/* { dg-do compile } */
+/* { dg-options "-std=c11 -pedantic-errors" } */
+/* { dg-add-options float16 } */
+/* { dg-require-effective-target float16 } */
+
+_Float16 a		/* { dg-error "ISO C does not support the '_Float16' type before C2X" } */
+  = 1.0F16;		/* { dg-error "non-standard suffix on floating constant before C2X" } */
+__extension__ _Float16 b
+  = 2.0F16;

gcc/testsuite/gcc.dg/c11-floatn-4.c

@@ -0,0 +1,9 @@
+/* { dg-do compile } */
+/* { dg-options "-std=c11 -pedantic-errors" } */
+/* { dg-add-options float64x } */
+/* { dg-require-effective-target float64x } */
+
+_Float64x a		/* { dg-error "ISO C does not support the '_Float64x' type before C2X" } */
+  = 1.0F64x;		/* { dg-error "non-standard suffix on floating constant before C2X" } */
+__extension__ _Float64x b
+  = 2.0F64x;

gcc/testsuite/gcc.dg/c11-floatn-5.c

@@ -0,0 +1,21 @@
+/* { dg-do compile } */
+/* { dg-options "-std=c11 -Wc11-c2x-compat" } */
+/* { dg-add-options float32 } */
+/* { dg-add-options float64 } */
+/* { dg-add-options float32x } */
+/* { dg-require-effective-target float32 } */
+/* { dg-require-effective-target float32x } */
+/* { dg-require-effective-target float64 } */
+
+_Float32 a		/* { dg-warning "ISO C does not support the '_Float32' type before C2X" } */
+  = 1.0F32;		/* { dg-warning "non-standard suffix on floating constant before C2X" } */
+_Float64 b		/* { dg-warning "ISO C does not support the '_Float64' type before C2X" } */
+  = 1.0F64;		/* { dg-warning "non-standard suffix on floating constant before C2X" } */
+_Float32x c		/* { dg-warning "ISO C does not support the '_Float32x' type before C2X" } */
+  = 1.0F32x;		/* { dg-warning "non-standard suffix on floating constant before C2X" } */
+__extension__ _Float32 d
+  = 2.0F32;
+__extension__ _Float64 e
+  = 2.0F64;
+__extension__ _Float32x f
+  = 2.0F32x;

gcc/testsuite/gcc.dg/c11-floatn-6.c

@@ -0,0 +1,9 @@
+/* { dg-do compile } */
+/* { dg-options "-std=c11 -Wc11-c2x-compat" } */
+/* { dg-add-options float128 } */
+/* { dg-require-effective-target float128 } */
+
+_Float128 a		/* { dg-warning "ISO C does not support the '_Float128' type before C2X" } */
+  = 1.0F128;		/* { dg-warning "non-standard suffix on floating constant before C2X" } */
+__extension__ _Float128 b
+  = 2.0F128;

gcc/testsuite/gcc.dg/c11-floatn-7.c

@@ -0,0 +1,9 @@
+/* { dg-do compile } */
+/* { dg-options "-std=c11 -Wc11-c2x-compat" } */
+/* { dg-add-options float16 } */
+/* { dg-require-effective-target float16 } */
+
+_Float16 a		/* { dg-warning "ISO C does not support the '_Float16' type before C2X" } */
+  = 1.0F16;		/* { dg-warning "non-standard suffix on floating constant before C2X" } */
+__extension__ _Float16 b
+  = 2.0F16;

gcc/testsuite/gcc.dg/c11-floatn-8.c

@@ -0,0 +1,9 @@
+/* { dg-do compile } */
+/* { dg-options "-std=c11 -Wc11-c2x-compat" } */
+/* { dg-add-options float64x } */
+/* { dg-require-effective-target float64x } */
+
+_Float64x a		/* { dg-warning "ISO C does not support the '_Float64x' type before C2X" } */
+  = 1.0F64x;		/* { dg-warning "non-standard suffix on floating constant before C2X" } */
+__extension__ _Float64x b
+  = 2.0F64x;

gcc/testsuite/gcc.dg/c2x-floatn-1.c

@@ -0,0 +1,21 @@
+/* { dg-do compile } */
+/* { dg-options "-std=c2x -pedantic-errors" } */
+/* { dg-add-options float32 } */
+/* { dg-add-options float64 } */
+/* { dg-add-options float32x } */
+/* { dg-require-effective-target float32 } */
+/* { dg-require-effective-target float32x } */
+/* { dg-require-effective-target float64 } */
+
+_Float32 a
+  = 1.0F32;
+_Float64 b
+  = 1.0F64;
+_Float32x c
+  = 1.0F32x;
+__extension__ _Float32 d
+  = 2.0F32;
+__extension__ _Float64 e
+  = 2.0F64;
+__extension__ _Float32x f
+  = 2.0F32x;

gcc/testsuite/gcc.dg/c2x-floatn-2.c

@@ -0,0 +1,9 @@
+/* { dg-do compile } */
+/* { dg-options "-std=c2x -pedantic-errors" } */
+/* { dg-add-options float128 } */
+/* { dg-require-effective-target float128 } */
+
+_Float128 a
+  = 1.0F128;
+__extension__ _Float128 b
+  = 2.0F128;

gcc/testsuite/gcc.dg/c2x-floatn-3.c

@@ -0,0 +1,9 @@
+/* { dg-do compile } */
+/* { dg-options "-std=c2x -pedantic-errors" } */
+/* { dg-add-options float16 } */
+/* { dg-require-effective-target float16 } */
+
+_Float16 a
+  = 1.0F16;
+__extension__ _Float16 b
+  = 2.0F16;

gcc/testsuite/gcc.dg/c2x-floatn-4.c

@@ -0,0 +1,9 @@
+/* { dg-do compile } */
+/* { dg-options "-std=c2x -pedantic-errors" } */
+/* { dg-add-options float64x } */
+/* { dg-require-effective-target float64x } */
+
+_Float64x a
+  = 1.0F64x;
+__extension__ _Float64x b
+  = 2.0F64x;

gcc/testsuite/gcc.dg/c2x-floatn-5.c

@@ -0,0 +1,21 @@
+/* { dg-do compile } */
+/* { dg-options "-std=c2x -Wc11-c2x-compat" } */
+/* { dg-add-options float32 } */
+/* { dg-add-options float64 } */
+/* { dg-add-options float32x } */
+/* { dg-require-effective-target float32 } */
+/* { dg-require-effective-target float32x } */
+/* { dg-require-effective-target float64 } */
+
+_Float32 a		/* { dg-warning "ISO C does not support the '_Float32' type before C2X" } */
+  = 1.0F32;		/* { dg-warning "non-standard suffix on floating constant before C2X" } */
+_Float64 b		/* { dg-warning "ISO C does not support the '_Float64' type before C2X" } */
+  = 1.0F64;		/* { dg-warning "non-standard suffix on floating constant before C2X" } */
+_Float32x c		/* { dg-warning "ISO C does not support the '_Float32x' type before C2X" } */
+  = 1.0F32x;		/* { dg-warning "non-standard suffix on floating constant before C2X" } */
+__extension__ _Float32 d
+  = 2.0F32;
+__extension__ _Float64 e
+  = 2.0F64;
+__extension__ _Float32x f
+  = 2.0F32x;

gcc/testsuite/gcc.dg/c2x-floatn-6.c

@@ -0,0 +1,9 @@
+/* { dg-do compile } */
+/* { dg-options "-std=c2x -Wc11-c2x-compat" } */
+/* { dg-add-options float128 } */
+/* { dg-require-effective-target float128 } */
+
+_Float128 a		/* { dg-warning "ISO C does not support the '_Float128' type before C2X" } */
+  = 1.0F128;		/* { dg-warning "non-standard suffix on floating constant before C2X" } */
+__extension__ _Float128 b
+  = 2.0F128;

gcc/testsuite/gcc.dg/c2x-floatn-7.c

@@ -0,0 +1,9 @@
+/* { dg-do compile } */
+/* { dg-options "-std=c2x -Wc11-c2x-compat" } */
+/* { dg-add-options float16 } */
+/* { dg-require-effective-target float16 } */
+
+_Float16 a		/* { dg-warning "ISO C does not support the '_Float16' type before C2X" } */
+  = 1.0F16;		/* { dg-warning "non-standard suffix on floating constant before C2X" } */
+__extension__ _Float16 b
+  = 2.0F16;

gcc/testsuite/gcc.dg/c2x-floatn-8.c

@@ -0,0 +1,9 @@
+/* { dg-do compile } */
+/* { dg-options "-std=c2x -Wc11-c2x-compat" } */
+/* { dg-add-options float64x } */
+/* { dg-require-effective-target float64x } */
+
+_Float64x a		/* { dg-warning "ISO C does not support the '_Float64x' type before C2X" } */
+  = 1.0F64x;		/* { dg-warning "non-standard suffix on floating constant before C2X" } */
+__extension__ _Float64x b
+  = 2.0F64x;