[Bug target/61633] New: AArch64 SISD ASHR instruction split clobbers input register.

[mshawcroft at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61633

            Bug ID: 61633
           Summary: AArch64 SISD ASHR instruction split clobbers input
                    register.
           Product: gcc
           Version: 4.9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: mshawcroft at gcc dot gnu.org

The FFT code in Android AAC codec at -O2 is incorrectly compiled resulting in
an infinite loop. I've failed to reduce the test case to something usable but
the problem in the back end is clearly the define_splits associated with
*aarch64_ashr_sisd_or_int_<mode>3.  Both of the splits inappropriately use one
of the input operand register as a scratch pad for the negated shift operand.