[AArch64] Tighten direct call pattern to repair -fno-plt

[AArch64] Tighten direct call pattern to repair -fno-plt

2015-08-06  Jiong Wang  <jiong.wang@arm.com>

gcc/
  * config/aarch64/aarch64-protos.h (aarch64_is_noplt_call_p): New declaration.
  * config/aarch64/aarch64.c (aarch64_is_noplt_call_p): New function.
  * config/aarch64/aarch64.md (call_value_symbol): Check noplt scenarios.
  (call_symbol): Likewise.

gcc/testsuite/
  * gcc.target/aarch64/noplt_1.c: New testcase.
  * gcc.target/aarch64/noplt_2.c: Likewise.

From-SVN: r226681