[PATCH] PR57518, RA generated redundent code

[H.J. Lu]

On Wed, Jun 12, 2013 at 2:44 PM, Wei Mi <wmi@google.com> wrote:
> Hi,
>
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57518
>
> pr57518 happened because update_equiv_regs in IRA marked a reg
> equivalent with a mem, lowered its mem_cost in scan_one_insn, set
> NO_REGS to its rclass, but didn't consider the reg was used in
> paradoxical subreg which prevented the reg from being replaced by mem
> in LRA phase.
>
> This patch is to check whether a reg is used in a paradoxical subreg
> in update_equiv_regs before reg is set as equivalent to a mem.
>
> bootstrap and regression test on x86_64-linux-gnu ok. Is it ok for
> trunk and gcc-4.8 branch?
>
> Thanks,
> Wei.

You need a testcase to verify that the problem is fixed.

--
H.J.