Following Richard Biener's patch at 
https://gcc.gnu.org/ml/gcc-patches/2015-03/msg01064.html (r221532), 
gcc.target/aarch64/c-output-template-3.c fails with:

c-output-template-3.c: In function 'test':
c-output-template-3.c:7:5: error: impossible constraint in 'asm'
      __asm__ ("@ %c0" : : "S" (&test + 4));

This patch fixes the test by changing options to -O in a similar manner to 
Richard's fixes to gcc.dg/pr15347.c and c-c++-common/pr19807-1.c.

Ok for trunk?

Cheers, Alan

gcc/testsuite/ChangeLog:

	gcc.target/aarch64/c-output-template.c: Add -O, remove
	-Wno-pointer-arith.