On Mon, Jan 14, 2019 at 12:49:33PM -0600, Aaron Sawdey wrote: > The patch for this was committed to trunk as 267562 (see below). Is this also > ok for backport to 8?
Yes please. Thanks! Segher > On 12/20/18 5:44 PM, Segher Boessenkool wrote: > > On Thu, Dec 20, 2018 at 05:34:54PM -0600, Aaron Sawdey wrote: > >> On 12/20/18 3:51 AM, Segher Boessenkool wrote: > >>> On Wed, Dec 19, 2018 at 01:53:05PM -0600, Aaron Sawdey wrote: > >>>> Because of POWER9 dd2.1 issues with certain unaligned vsx instructions > >>>> to cache inhibited memory, here is a patch that keeps memmove (and > >>>> memcpy) > >>>> inline expansion from doing unaligned vector or using vector load/store > >>>> other than lvx/stvx. More description of the issue is here: > >>>> > >>>> https://patchwork.ozlabs.org/patch/814059/ > >>>> > >>>> OK for trunk if bootstrap/regtest ok? > >>> > >>> Okay, but see below. > >>> > >> [snip] > >>> > >>> This is extraordinarily clumsy :-) Maybe something like: > >>> > >>> static rtx > >>> gen_lvx_v4si_move (rtx dest, rtx src) > >>> { > >>> gcc_assert (!(MEM_P (dest) && MEM_P (src)); > >>> gcc_assert (GET_MODE (dest) == V4SImode && GET_MODE (src) == V4SImode); > >>> if (MEM_P (dest)) > >>> return gen_altivec_stvx_v4si_internal (dest, src); > >>> else if (MEM_P (src)) > >>> return gen_altivec_lvx_v4si_internal (dest, src); > >>> else > >>> gcc_unreachable (); > >>> } > >>> > >>> (Or do you allow VOIDmode for src as well?) Anyway, at least get rid of > >>> the useless extra variable. > >> > >> I think this should be better: > > > > The gcc_unreachable at the end catches the non-mem to non-mem case. > > > >> static rtx > >> gen_lvx_v4si_move (rtx dest, rtx src) > >> { > >> gcc_assert ((MEM_P (dest) && !MEM_P (src)) || (MEM_P (src) && > >> !MEM_P(dest))); > > > > But if you prefer this, how about > > > > { > > gcc_assert (MEM_P (dest) ^ MEM_P (src)); > > gcc_assert (GET_MODE (dest) == V4SImode && GET_MODE (src) == V4SImode); > > > > if (MEM_P (dest)) > > return gen_altivec_stvx_v4si_internal (dest, src); > > else > > return gen_altivec_lvx_v4si_internal (dest, src); > > } > > > > :-) > > > > > > Segher > > > > 2019-01-03 Aaron Sawdey <acsaw...@linux.ibm.com> > > * config/rs6000/rs6000-string.c (expand_block_move): Don't use > unaligned vsx and avoid lxvd2x/stxvd2x. > (gen_lvx_v4si_move): New function. > > > Index: gcc/config/rs6000/rs6000-string.c > =================================================================== > --- gcc/config/rs6000/rs6000-string.c (revision 267299) > +++ gcc/config/rs6000/rs6000-string.c (working copy) > @@ -2669,6 +2669,25 @@ > return true; > } > > +/* Generate loads and stores for a move of v4si mode using lvx/stvx. > + This uses altivec_{l,st}vx_<mode>_internal which use unspecs to > + keep combine from changing what instruction gets used. > + > + DEST is the destination for the data. > + SRC is the source of the data for the move. */ > + > +static rtx > +gen_lvx_v4si_move (rtx dest, rtx src) > +{ > + gcc_assert (MEM_P (dest) ^ MEM_P (src)); > + gcc_assert (GET_MODE (dest) == V4SImode && GET_MODE (src) == V4SImode); > + > + if (MEM_P (dest)) > + return gen_altivec_stvx_v4si_internal (dest, src); > + else > + return gen_altivec_lvx_v4si_internal (dest, src); > +} > + > /* Expand a block move operation, and return 1 if successful. Return 0 > if we should let the compiler generate normal code. > > @@ -2721,11 +2740,11 @@ > > /* Altivec first, since it will be faster than a string move > when it applies, and usually not significantly larger. */ > - if (TARGET_ALTIVEC && bytes >= 16 && (TARGET_EFFICIENT_UNALIGNED_VSX > || align >= 128)) > + if (TARGET_ALTIVEC && bytes >= 16 && align >= 128) > { > move_bytes = 16; > mode = V4SImode; > - gen_func.mov = gen_movv4si; > + gen_func.mov = gen_lvx_v4si_move; > } > else if (bytes >= 8 && TARGET_POWERPC64 > && (align >= 64 || !STRICT_ALIGNMENT)) > > > > -- > Aaron Sawdey, Ph.D. acsaw...@linux.vnet.ibm.com > 050-2/C113 (507) 253-7520 home: 507/263-0782 > IBM Linux Technology Center - PPC Toolchain
