Re: C++ PATCH to add __integer_pack built-in for std::make_integer_sequence (c++/80396)

[Jakub Jelinek <jakub@redhat.com>]

On Wed, May 24, 2017 at 02:47:08PM -0400, Jason Merrill wrote:
> On Wed, May 24, 2017 at 11:08 AM, Jakub Jelinek <jakub@redhat.com> wrote:
> > On Wed, May 24, 2017 at 04:16:30PM +0200, Andreas Schwab wrote:
> >> FAIL: g++.dg/ext/integer-pack2.C  -std=gnu++11 (test for excess errors)
> >> Excess errors:
> >> /daten/aranym/gcc/gcc-20170524/gcc/testsuite/g++.dg/ext/integer-pack2.C:10:48: error: overflow in constant expression [-fpermissive]
> >> /daten/aranym/gcc/gcc-20170524/gcc/testsuite/g++.dg/ext/integer-pack2.C:10:48: error: overflow in constant expression [-fpermissive]
> >
> > To be precise, it fails only on 32-bit targets.
> 
> > If we at that point want some wider integer that when cast to int
> > is 0 (or small enough positive number?), shall we use something like
> > this, or say 1LL << (sizeof (int) * __CHAR_BIT__), or 2LL * INT_MIN,
> > something else?
> 
> This is fine.
> 
> > Do we need to include <limits.h>?  Or can we replace
> > INT_MAX with __INT_MAX__?
> 
> __INT_MAX__ sounds good.
> 
> > Not sure about that -2147483650 for 16-bit int targets (perhaps the test can
> > be guarded with int32 effective target).
> 
> Yes, restricting the test to int32 seems like the easiest fix.

Ok, I've committed this (also add something to avoid failing on hypothetical
64-bit int 64-bit long long target).  Tested for both -m32 and -m64 on
x86_64-linux.

2017-05-24  Jakub Jelinek  <jakub@redhat.com>

	* g++.dg/ext/integer-pack2.C: Require int32 effective target.
	Don't include limits.h.
	(w): Conditionalize on long long wider than int.  Use
	1LL << (__SIZEOF_INT__ * __CHAR_BIT__) instead of
	-9223372036854775808.
	(x): Use __INT_MAX__ instead of INT_MAX.

--- gcc/testsuite/g++.dg/ext/integer-pack2.C.jj	2017-05-24 11:59:01.000000000 +0200
+++ gcc/testsuite/g++.dg/ext/integer-pack2.C	2017-05-24 21:07:02.000000000 +0200
@@ -1,12 +1,12 @@
-// { dg-do compile { target c++11 } }
+// { dg-do compile { target { c++11 && int32 } } }
 // { dg-options -w }
 
-#include <limits.h>
-
 template<typename T, T...> struct integer_sequence { };
 template<typename T, T num>
  using make_integer_sequence = integer_sequence<T, __integer_pack(num)...>; // { dg-error "argument" }
 
-make_integer_sequence<int, -9223372036854775808> w;
-make_integer_sequence<int, INT_MAX> x;	   // { dg-message "required" }
+#if __SIZEOF_LONG_LONG__ > __SIZEOF_INT__
+make_integer_sequence<int, 1LL << (__SIZEOF_INT__ * __CHAR_BIT__)> w;
+#endif
+make_integer_sequence<int, __INT_MAX__> x; // { dg-message "required" }
 make_integer_sequence<int, -2147483650> y; // { dg-message "required" }


	Jakub