C++ PATCH for c++/49813 (c99 builtins in c++0x mode)

C++ PATCH for c++/49813 (c99 builtins in c++0x mode)

[Jason Merrill]

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C++0x references the C99 standard, so in C++0x mode we should have the 
C99 builtins.

Tested x86_64-pc-linux-gnu, applying to trunk.

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commit fc181abfe4b268602287b2cd036035ab40685b9b
Author: Jason Merrill <jason@redhat.com>
Date:   Fri Jul 22 10:43:00 2011 -0400

    	PR c++/49813
    	* c-opts.c (set_std_cxx0x): Set flag_isoc94 and flag_isoc99.
    	* c-pretty-print.c (pp_c_cv_qualifiers): Check c_dialect_cxx as well
    	as flag_isoc99 for 'restrict'.
    	(pp_c_specifier_qualifier_list): Likewise for _Complex.

diff --git a/gcc/c-family/c-opts.c b/gcc/c-family/c-opts.c
index 5cf58ac..3227f7b 100644
--- a/gcc/c-family/c-opts.c
+++ b/gcc/c-family/c-opts.c
@@ -1488,6 +1488,9 @@ set_std_cxx0x (int iso)
   flag_no_gnu_keywords = iso;
   flag_no_nonansi_builtin = iso;
   flag_iso = iso;
+  /* C++0x includes the C99 standard library.  */
+  flag_isoc94 = 1;
+  flag_isoc99 = 1;
   cxx_dialect = cxx0x;
 }
 
diff --git a/gcc/c-family/c-pretty-print.c b/gcc/c-family/c-pretty-print.c
index 977f79e..53d39d6 100644
--- a/gcc/c-family/c-pretty-print.c
+++ b/gcc/c-family/c-pretty-print.c
@@ -205,7 +205,8 @@ pp_c_cv_qualifiers (c_pretty_printer *pp, int qualifiers, bool func_type)
     {
       if (previous)
         pp_c_whitespace (pp);
-      pp_c_ws_string (pp, flag_isoc99 ? "restrict" : "__restrict__");
+      pp_c_ws_string (pp, (flag_isoc99 && !c_dialect_cxx ()
+			   ? "restrict" : "__restrict__"));
     }
 }
 
@@ -476,7 +477,8 @@ pp_c_specifier_qualifier_list (c_pretty_printer *pp, tree t)
     case VECTOR_TYPE:
     case COMPLEX_TYPE:
       if (code == COMPLEX_TYPE)
-	pp_c_ws_string (pp, flag_isoc99 ? "_Complex" : "__complex__");
+	pp_c_ws_string (pp, (flag_isoc99 && !c_dialect_cxx ()
+			     ? "_Complex" : "__complex__"));
       else if (code == VECTOR_TYPE)
 	{
 	  pp_c_ws_string (pp, "__vector");
diff --git a/gcc/testsuite/g++.dg/opt/builtins2.C b/gcc/testsuite/g++.dg/opt/builtins2.C
new file mode 100644
index 0000000..00a28db
--- /dev/null
+++ b/gcc/testsuite/g++.dg/opt/builtins2.C
@@ -0,0 +1,11 @@
+// PR c++/49813
+// We should handle asinh as a built-in in C++0x mode, even when strict.
+// { dg-options "-std=c++0x" }
+// { dg-final { scan-assembler-not "asinh" } }
+
+#include <math.h>
+
+int main()
+{
+  double das = asinh(1.0);
+}
diff --git a/gcc/testsuite/g++.dg/other/error27.C b/gcc/testsuite/g++.dg/other/error27.C
index de97428..ef1e590 100644
--- a/gcc/testsuite/g++.dg/other/error27.C
+++ b/gcc/testsuite/g++.dg/other/error27.C
@@ -4,10 +4,10 @@
 
 void foo (double x, double y)
 {
-  __builtin_isgreater(x, y)();		// { dg-error "__builtin_\[^\n\]*cannot be used as a function" }
-  __builtin_isless(x, y)();		// { dg-error "__builtin_\[^\n\]*cannot be used as a function" }
-  __builtin_isgreaterequal(x, y)();	// { dg-error "__builtin_\[^\n\]*cannot be used as a function" }
-  __builtin_islessequal(x, y)();	// { dg-error "__builtin_\[^\n\]*cannot be used as a function" }
-  __builtin_isunordered(x, y)();	// { dg-error "__builtin_\[^\n\]*cannot be used as a function" }
-  __builtin_islessgreater(x, y)();	// { dg-error "__builtin_\[^\n\]*cannot be used as a function" }
+  __builtin_isgreater(x, y)();		// { dg-error "cannot be used as a function" }
+  __builtin_isless(x, y)();		// { dg-error "cannot be used as a function" }
+  __builtin_isgreaterequal(x, y)();	// { dg-error "cannot be used as a function" }
+  __builtin_islessequal(x, y)();	// { dg-error "cannot be used as a function" }
+  __builtin_isunordered(x, y)();	// { dg-error "cannot be used as a function" }
+  __builtin_islessgreater(x, y)();	// { dg-error "cannot be used as a function" }
 }

Re: C++ PATCH for c++/49813 (__builtin_isinf in constant expression)

[Jason Merrill]

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Another issue raised in 49813 is that 
morally_constexpr_builtin_function_p was rejecting __builtin_isinf 
because it has a variadic signature.  I'm changing 
potential_constant_expression_1 to just allow any built-in function in a 
constexpr function; if it doesn't expand to a constant, we'll deal with 
that when we actually expand it.

Tested x86_64-pc-linux-gnu, applying to trunk.


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commit e2a2b30a8008b9f2d21e19bb2fd73776dbf89576
Author: Jason Merrill <jason@redhat.com>
Date:   Mon Aug 1 11:49:09 2011 -0400

    	PR c++/49813
    	* semantics.c (potential_constant_expression_1): Allow any builtin.
    	(morally_constexpr_builtin_function_p): Remove.

diff --git a/gcc/cp/semantics.c b/gcc/cp/semantics.c
index c44c0ef..47b714f 100644
--- a/gcc/cp/semantics.c
+++ b/gcc/cp/semantics.c
@@ -7523,32 +7523,6 @@ check_automatic_or_tls (tree ref)
 }
 #endif
 
-/* Return true if the DECL designates a builtin function that is
-   morally constexpr, in the sense that its parameter types and
-   return type are literal types and the compiler is allowed to
-   fold its invocations.  */
-
-static bool
-morally_constexpr_builtin_function_p (tree decl)
-{
-  tree funtype = TREE_TYPE (decl);
-  tree t;
-
-  if (!is_builtin_fn (decl))
-    return false;
-  if (!literal_type_p (TREE_TYPE (funtype)))
-    return false;
-  for (t = TYPE_ARG_TYPES (funtype); t != NULL ; t = TREE_CHAIN (t))
-    {
-      if (t == void_list_node)
-        return true;
-      if (!literal_type_p (TREE_VALUE (t)))
-        return false;
-    }
-  /* We assume no varargs builtins are suitable.  */
-  return t != NULL;
-}
-
 /* Return true if T denotes a potentially constant expression.  Issue
    diagnostic as appropriate under control of FLAGS.  If WANT_RVAL is true,
    an lvalue-rvalue conversion is implied.
@@ -7656,7 +7630,9 @@ potential_constant_expression_1 (tree t, bool want_rval, tsubst_flags_t flags)
 		if (builtin_valid_in_constant_expr_p (fun))
 		  return true;
 		if (!DECL_DECLARED_CONSTEXPR_P (fun)
-		    && !morally_constexpr_builtin_function_p (fun))
+		    /* Allow any built-in function; if the expansion
+		       isn't constant, we'll deal with that then.  */
+		    && !is_builtin_fn (fun))
 		  {
 		    if (flags & tf_error)
 		      {
diff --git a/gcc/testsuite/g++.dg/cpp0x/constexpr-builtin1.C b/gcc/testsuite/g++.dg/cpp0x/constexpr-builtin1.C
new file mode 100644
index 0000000..b3f5576
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/constexpr-builtin1.C
@@ -0,0 +1,25 @@
+// PR c++/49813
+// { dg-options -std=c++0x }
+
+inline constexpr bool
+isinf(long double __x)
+{ return __builtin_isinf(__x); }
+
+inline constexpr bool
+isinf(double __x)
+{ return __builtin_isinf(__x); }
+
+inline constexpr bool
+isnan(long double __x)
+{ return __builtin_isnan(__x); }
+
+int main()
+{
+  constexpr long double num1 = __builtin_isinf(1.l); // Ok.
+
+  constexpr long double num2 = isinf(1.l);           // Error.
+
+  constexpr double      num3 = isinf(1.);            // Ok.
+
+  constexpr long double num4 = isnan(1.l);           // Ok.
+}

Re: C++ PATCH for c++/49813 (__builtin_isinf in constant expression)

[Paolo Carlini]

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Thanks a lot, Jason.

I applied the below, tested x86_64-linux multilib.

Paolo.

//////////////////////


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2011-08-01  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/49813
	* include/c_global/cmath (isinf): Remove workaround.

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Index: include/c_global/cmath
===================================================================
--- include/c_global/cmath	(revision 177068)
+++ include/c_global/cmath	(working copy)
@@ -547,18 +547,17 @@
     isfinite(_Tp __x)
     { return true; }
 
-  // Workaround the isinf issue discussed in PR 49813.
   constexpr bool
   isinf(float __x)
-  { return fpclassify(__x) == FP_INFINITE; }
+  { return __builtin_isinf(__x); }
 
   constexpr bool
   isinf(double __x)
-  { return fpclassify(__x) == FP_INFINITE; }
+  { return __builtin_isinf(__x); }
 
   constexpr bool
   isinf(long double __x)
-  { return fpclassify(__x) == FP_INFINITE; }
+  { return __builtin_isinf(__x); }
 
   template<typename _Tp>
     constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value,

Re: C++ PATCH for c++/49813 (__builtin_isinf in constant expression)

[Gabriel Dos Reis]

On Mon, Aug 1, 2011 at 1:12 PM, Jason Merrill <jason@redhat.com> wrote:
> Another issue raised in 49813 is that morally_constexpr_builtin_function_p
> was rejecting __builtin_isinf because it has a variadic signature.  I'm
> changing potential_constant_expression_1 to just allow any built-in function
> in a constexpr function; if it doesn't expand to a constant, we'll deal with
> that when we actually expand it.

OK; at the time, I did not form a firm policy about variadic builtins.