On 20/11/18 17:58 -0500, Ed Smith-Rowland wrote:
On 11/19/18 6:13 AM, Jonathan Wakely wrote:
On 16/11/18 19:39 -0500, Ed Smith-Rowland wrote:
@@ -322,67 +323,43 @@
//@{
/// Return new complex value @a x plus @a y.
template<typename _Tp>
- inline complex<_Tp>
+ inline _GLIBCXX20_CONSTEXPR complex<_Tp>
operator+(const complex<_Tp>& __x, const complex<_Tp>& __y)
- {
- complex<_Tp> __r = __x;
- __r += __y;
- return __r;
- }
+ { return complex<_Tp>(__x.real() + __y.real(), __x.imag() +
__y.imag()); }
Is this change (and all the similar ones) really needed?
Doesn't the fact that all the constructors and member operators of
std::complex mean that the original definition is also valid in a
constexpr function?
These changes are rolled back. Sorry.
@@ -1163,50 +1143,43 @@
#endif
template<typename _Tp>
- complex&
+ _GLIBCXX20_CONSTEXPR complex&
operator=(const complex<_Tp>& __z)
{
- __real__ _M_value = __z.real();
- __imag__ _M_value = __z.imag();
+ _M_value = __z.__rep();
These changes look OK, but I wonder if we shouldn't ask the compiler
to make it possible to use __real__ and __imag__ in constexpr
functions instead.
I assume it doesn't, and that's why you made this change. But if it
Just Worked, and the other changes I commented on above are also
unnecessary, then this patch would *mostly* just be adding
_GLIBCXX20_CONSTEXPR which is OK for stage 3 (as it doesn't affect any
dialects except C++2a).
Yes, this is the issue. I agree that constexpr _real__, __imag__would
be better.
Do you have any idea where this change would be? I grepped around a
little and couldn't figure it out. if you don't I'll look more.
No idea, sorry.
Actually, looking at constexpr.c it looks like the old way ought to work...
OK, plain assignment works but not the others. Interesting.
@@ -1872,7 +1831,7 @@
{ return _Tp(); }
template<typename _Tp>
- inline typename __gnu_cxx::__promote<_Tp>::__type
+ _GLIBCXX_CONSTEXPR inline typename
__gnu_cxx::__promote<_Tp>::__type
This should be _GLIBCXX20_CONSTEXPR.
Done.
Index:
testsuite/26_numerics/complex/comparison_operators/more_constexpr.cc
===================================================================
---
testsuite/26_numerics/complex/comparison_operators/more_constexpr.cc
(nonexistent)
+++
testsuite/26_numerics/complex/comparison_operators/more_constexpr.cc
(working copy)
@@ -0,0 +1,51 @@
+// { dg-do compile { target c++2a } }
All the tests with { target c++2a} should also have:
// { dg-options "-std=gnu++2a" }
Because otherwise they are skipped by default, and only get run when
RUNTESTFLAGS explicitly includes something like
--target_board=unix/-std=gnu++2a
The dg-options needs to come first, or it doesn't apply before the
check for { target c++2a }.
Thank you, done.
OK for trunk, thanks.
Updated patch attached. I'd like to understand why
__real__ _M_value += __z.real();
doesn't work though.
Yes, I agree it should. If you don't figure it out please file a bug
requesting that it works, so somebody else might look into it.
