On Thu, Jan 16, 2020 at 5:14 AM Richard Sandiford
<[email protected]> wrote:
>
> Wilco Dijkstra <[email protected]> writes:
> > The separate shrinkwrapping pass may insert stores in the middle
> > of atomics loops which can cause issues on some implementations.
> > Avoid this by delaying splitting of atomic patterns until after
> > prolog/epilog generation.
> >
> > Bootstrap completed, no test regressions on AArch64.
> >
> > Andrew, can you verify this fixes the failure you were getting?
> >
> > ChangeLog:
> > 2020-01-16 Wilco Dijkstra <[email protected]>
> >
> > PR target/92692
> > * config/aarch64/aarch64.c (aarch64_split_compare_and_swap)
> > Add assert to ensure prolog has been emitted.
> > (aarch64_split_atomic_op): Likewise.
> > * config/aarch64/atomics.md (aarch64_compare_and_swap<mode>)
> > Use epilogue_completed rather than reload_completed.
> > (aarch64_atomic_exchange<mode>): Likewise.
> > (aarch64_atomic_<atomic_optab><mode>): Likewise.
> > (atomic_nand<mode>): Likewise.
> > (aarch64_atomic_fetch_<atomic_optab><mode>): Likewise.
> > (atomic_fetch_nand<mode>): Likewise.
> > (aarch64_atomic_<atomic_optab>_fetch<mode>): Likewise.
> > (atomic_nand_fetch<mode>): Likewise.
>
> OK if Andrew confirms it works, thanks.
Yes this fixes the issue for me.
Thanks,
Andrew
>
> Richard
>
> > ---
> >
> > diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
> > index
> > ac89cc1f9c938455d33d8850d9ebfc0473cb73dc..cd9d813f2ac4990971f6435fdb28b0f94ae10309
> > 100644
> > --- a/gcc/config/aarch64/aarch64.c
> > +++ b/gcc/config/aarch64/aarch64.c
> > @@ -18375,6 +18375,9 @@ aarch64_emit_post_barrier (enum memmodel model)
> > void
> > aarch64_split_compare_and_swap (rtx operands[])
> > {
> > + /* Split after prolog/epilog to avoid interactions with shrinkwrapping.
> > */
> > + gcc_assert (epilogue_completed);
> > +
> > rtx rval, mem, oldval, newval, scratch, x, model_rtx;
> > machine_mode mode;
> > bool is_weak;
> > @@ -18469,6 +18472,9 @@ void
> > aarch64_split_atomic_op (enum rtx_code code, rtx old_out, rtx new_out, rtx
> > mem,
> > rtx value, rtx model_rtx, rtx cond)
> > {
> > + /* Split after prolog/epilog to avoid interactions with shrinkwrapping.
> > */
> > + gcc_assert (epilogue_completed);
> > +
> > machine_mode mode = GET_MODE (mem);
> > machine_mode wmode = (mode == DImode ? DImode : SImode);
> > const enum memmodel model = memmodel_from_int (INTVAL (model_rtx));
> > diff --git a/gcc/config/aarch64/atomics.md b/gcc/config/aarch64/atomics.md
> > index
> > c2bcabd0c3c2627b7222dcbc1af9c2e6b7ce6a76..996947799b5ef8445e9786b94e1ce62fd16e5b5c
> > 100644
> > --- a/gcc/config/aarch64/atomics.md
> > +++ b/gcc/config/aarch64/atomics.md
> > @@ -56,7 +56,7 @@ (define_insn_and_split "@aarch64_compare_and_swap<mode>"
> > (clobber (match_scratch:SI 7 "=&r"))]
> > ""
> > "#"
> > - "&& reload_completed"
> > + "&& epilogue_completed"
> > [(const_int 0)]
> > {
> > aarch64_split_compare_and_swap (operands);
> > @@ -80,7 +80,7 @@ (define_insn_and_split "@aarch64_compare_and_swap<mode>"
> > (clobber (match_scratch:SI 7 "=&r"))]
> > ""
> > "#"
> > - "&& reload_completed"
> > + "&& epilogue_completed"
> > [(const_int 0)]
> > {
> > aarch64_split_compare_and_swap (operands);
> > @@ -104,7 +104,7 @@ (define_insn_and_split "@aarch64_compare_and_swap<mode>"
> > (clobber (match_scratch:SI 7 "=&r"))]
> > ""
> > "#"
> > - "&& reload_completed"
> > + "&& epilogue_completed"
> > [(const_int 0)]
> > {
> > aarch64_split_compare_and_swap (operands);
> > @@ -223,7 +223,7 @@ (define_insn_and_split "aarch64_atomic_exchange<mode>"
> > (clobber (match_scratch:SI 4 "=&r"))]
> > ""
> > "#"
> > - "&& reload_completed"
> > + "&& epilogue_completed"
> > [(const_int 0)]
> > {
> > aarch64_split_atomic_op (SET, operands[0], NULL, operands[1],
> > @@ -344,7 +344,7 @@ (define_insn_and_split
> > "aarch64_atomic_<atomic_optab><mode>"
> > (clobber (match_scratch:SI 4 "=&r"))]
> > ""
> > "#"
> > - "&& reload_completed"
> > + "&& epilogue_completed"
> > [(const_int 0)]
> > {
> > aarch64_split_atomic_op (<CODE>, NULL, operands[3], operands[0],
> > @@ -400,7 +400,7 @@ (define_insn_and_split "atomic_nand<mode>"
> > (clobber (match_scratch:SI 4 "=&r"))]
> > ""
> > "#"
> > - "&& reload_completed"
> > + "&& epilogue_completed"
> > [(const_int 0)]
> > {
> > aarch64_split_atomic_op (NOT, NULL, operands[3], operands[0],
> > @@ -504,7 +504,7 @@ (define_insn_and_split
> > "aarch64_atomic_fetch_<atomic_optab><mode>"
> > (clobber (match_scratch:SI 5 "=&r"))]
> > ""
> > "#"
> > - "&& reload_completed"
> > + "&& epilogue_completed"
> > [(const_int 0)]
> > {
> > aarch64_split_atomic_op (<CODE>, operands[0], operands[4], operands[1],
> > @@ -551,7 +551,7 @@ (define_insn_and_split "atomic_fetch_nand<mode>"
> > (clobber (match_scratch:SI 5 "=&r"))]
> > ""
> > "#"
> > - "&& reload_completed"
> > + "&& epilogue_completed"
> > [(const_int 0)]
> > {
> > aarch64_split_atomic_op (NOT, operands[0], operands[4], operands[1],
> > @@ -604,7 +604,7 @@ (define_insn_and_split
> > "aarch64_atomic_<atomic_optab>_fetch<mode>"
> > (clobber (match_scratch:SI 4 "=&r"))]
> > ""
> > "#"
> > - "&& reload_completed"
> > + "&& epilogue_completed"
> > [(const_int 0)]
> > {
> > aarch64_split_atomic_op (<CODE>, NULL, operands[0], operands[1],
> > @@ -628,7 +628,7 @@ (define_insn_and_split "atomic_nand_fetch<mode>"
> > (clobber (match_scratch:SI 4 "=&r"))]
> > ""
> > "#"
> > - "&& reload_completed"
> > + "&& epilogue_completed"
> > [(const_int 0)]
> > {
> > aarch64_split_atomic_op (NOT, NULL, operands[0], operands[1],
