[AArch64] Fix register clobber in, aarch64_ashr_sisd_or_int_<mode>3 split.

[AArch64] Fix register clobber in, aarch64_ashr_sisd_or_int_<mode>3 split.

PR target/61633

The two split patterns associated with
aarch64_ashr_sisd_or_int_<mode>3 split the instruction into a NEG
followed by an SHL.  The split uses one of the input operands as a
scratch register to hold the output of the NEG resulting in register
corruption.

This patch adjusts the splits to use the output operand as the scratch
register.

2014-06-30  Marcus Shawcroft  <marcus.shawcroft@arm.com>

       PR target/61633
       * config/aarch64/aarch64.md (*aarch64_ashr_sisd_or_int_<mode>3):
       Add alternative; make early clobber.  Adjust both split patterns
       to use operand 0 as the working register.

From-SVN: r212137