Re: [PATCH, powerpc], Fix PR48857, pass/return V2DI as other vector types

[David Edelsohn <dje dot gcc at gmail dot com>]

On Tue, May 3, 2011 at 5:27 PM, Michael Meissner
<meissner@linux.vnet.ibm.com> wrote:
> When I added VSX support to the powerpc, I overlooked passing and return
> V2DImode arguments, since the only machine operation that supports V2DI is
> vector floating point conversion. ?Consequentally, V2DI types were passed and
> returned in GPRs instead of the vector registers on power7.
>
> This patch fixes that so that V2DImode values are passed and returned like
> other vector types.
>
> I did a bootstrap and make check with no regressions, comparing it to a build
> without the patch. ?I also wrote a program that passed and returned every
> single type, and I compared the assembly ouptut. ?With the exception of
> functions that return or are passed V2DI arguments, the code is identical. ?I
> tested:
>
> ? ? ? ?-m64 ? ? ? ? ? ? ? ? ? ?(implies -mabi=altivec)
> ? ? ? ?-m32 -mabi=altivec
> ? ? ? ?-m32 -mabi=no-altivec ? (no difference here)
>
> Is this patch ok to install? ?I will also want to install it in the 4.6 and
> possibly 4.5 trees as well.
>
> [gcc]
> 2011-05-03 ?Michael Meissner ?<meissner@linux.vnet.ibm.com>
>
> ? ? ? ?PR target/48857
> ? ? ? ?* config/rs6000/rs6000.h (VSX_SCALAR_MODE): Delete.
> ? ? ? ?(VSX_MODE): Ditto.
> ? ? ? ?(VSX_MOVE_MODE): Ditto.
> ? ? ? ?(ALTIVEC_OR_VSX_VECTOR_MODE): New macro, combine all Altivec and
> ? ? ? ?VSX vector types. ?Add V2DImode.
> ? ? ? ?(HARD_REGNO_CALLER_SAVE_MODE): Use it instead of
> ? ? ? ?ALTIVEC_VECTOR_MODE and VSX_VECTOR_MODE calls.
> ? ? ? ?(MODES_TIEABLE_P): Ditto.
>
> ? ? ? ?* config/rs6000/rs6000.c (rs6000_emit_move): Use
> ? ? ? ?ALTIVEC_OR_VSX_MODE instead of ALTIVEC_VECTOR_MODE and
> ? ? ? ?VSX_VECTOR_MODE.
> ? ? ? ?(init_cumulative_args): Ditto.
> ? ? ? ?(rs6000_function_arg_boundary): Ditto.
> ? ? ? ?(rs6000_function_arg_advance_1): Ditto.
> ? ? ? ?(rs6000_function_arg): Ditto.
> ? ? ? ?(rs6000_function_ok_for_sibcall): Ditto.
> ? ? ? ?(emit_frame_save): Ditto.
> ? ? ? ?(rs6000_function_value): Ditto.
> ? ? ? ?(rs6000_libcall_value): Ditto.
>
> [gcc/testsuite]
> 2011-05-03 ?Michael Meissner ?<meissner@linux.vnet.ibm.com>
>
> ? ? ? ?PR target/48857
> ? ? ? ?* gcc.target/powerpc/pr48857.c: New file, make sure V2DI arguments
> ? ? ? ?are passed and returned in vector registers.

The patch is okay, but please add a comment explaining why the
function_value and libcall_value changes are correct.

Thanks, David