Hi,
The test case is like below.
/* { dg-do compile { target arm*-*-* } } */
/* { dg-options "-mfp16-format=ieee" } */

/* Test mangling */

/* { dg-final { scan-assembler "\t.global\t_Z1fPDh" } } */
void f (__fp16 *x) { }

/* { dg-final { scan-assembler "\t.global\t_Z1gPDhS_" } } */
void g (__fp16 *x, __fp16 *y) { }

/* { dg-final { scan-assembler "\t.global\t_ZN1SIDhDhE1iE" } } */
template <typename T, typename U> struct S { static int i; }; 
template <> int S<__fp16, __fp16>::i = 3;

But the generated assembly code is like.

	.weak	_ZN1SIDhDhE1iE
	.section	.data._ZN1SIDhDhE1iE,"awG",%progbits,_ZN1SIDhDhE1iE,comdat
	.align	2
	.type	_ZN1SIDhDhE1iE, %object
	.size	_ZN1SIDhDhE1iE, 4
_ZN1SIDhDhE1iE:
	.word	3
	.ident	"GCC: (GNU) 4.10.0 20140811 (experimental)"

In which _ZN1SIDhDhE1iE is weak, rather than global.

This starts from r213307 and as stated by Jason at https://gcc.gnu.org/ml/gcc-patches/2014-08/msg01483.html.  It is a bug?

I know little about c++, so better leave it to an expert.

Thanks very much.