Hi Richard,
On Wed, Jul 12, 2017 at 05:33:42PM +0100, Richard Sandiford wrote:
> The little-endian VSX code uses rotates to swap the two 64-bit halves of
> 128-bit scalar modes. This is fine for TImode and V1TImode, but it
> isn't really valid to use RTL rotates on floating-point modes like
> KFmode and TFmode, and doing that triggered an assert added by the
> SVE series. This patch uses bit-casts to V1TImode instead.
>
> Tested on powerpc64le-linux-gnu. OK to install?
> +void
> +rs6000_emit_le_vsx_permute (rtx dest, rtx source, machine_mode mode)
> {
> /* Use ROTATE instead of VEC_SELECT on IEEE 128-bit floating point, and
> 128-bit integers if they are allowed in VSX registers. */
> - if (FLOAT128_VECTOR_P (mode) || mode == TImode || mode == V1TImode)
> - return gen_rtx_ROTATE (mode, source, GEN_INT (64));
> + if (FLOAT128_VECTOR_P (mode))
> + {
> + dest = gen_lowpart (V1TImode, dest);
> + source = gen_lowpart (V1TImode, source);
> + mode = V1TImode;
> + }
Add an empty line here? And maybe a comment.
> + if (mode == TImode || mode == V1TImode)
> + emit_insn (gen_rtx_SET (dest, gen_rtx_ROTATE (mode, source,
> + GEN_INT (64))));
> else
> {
> rtx par = gen_rtx_PARALLEL (VOIDmode, rs6000_const_vec (mode));
> - return gen_rtx_VEC_SELECT (mode, source, par);
> + emit_insn (gen_rtx_SET (dest, gen_rtx_VEC_SELECT (mode, source, par)));
> }
> }
> --- gcc/config/rs6000/vsx.md 2017-06-30 12:50:38.889632907 +0100
> +++ gcc/config/rs6000/vsx.md 2017-07-12 16:30:38.734631598 +0100
> @@ -37,6 +37,10 @@ (define_mode_iterator VSX_LE_128 [(KF
> (TI "TARGET_VSX_TIMODE")
> V1TI])
>
> +;; Same, but with just the integer modes.
> +(define_mode_iterator VSX_LE_128I [(TI "TARGET_VSX_TIMODE")
> + V1TI])
I don't like that name much. The difference between VSX_LE_128 and
VSX_LE_128I is easy to overlook (and what _is_ the difference? "I"
means "integer" I guess?). The "LE" in the name has no real meaning
(it is used for LE, sure, but that doesn't matter for the iterator).
Maybe just VSX_TI? Or is that too short.
Other than that, looks fine. Thank you for the patch!
Does this need backports?
Segher
