On Thu, Jan 16, 2020 at 5:51 PM Andrew Pinski <[email protected]> wrote:
>
> 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.
Here is the new assembly showing it worked:
d390: f9000bf3 str x19, [sp, #16]
d394: 885ffdc8 ldaxr w8, [x14]
d398: 6b01011f cmp w8, w1
d39c: 54000061 b.ne d3a8
<pthread_rwlock_clockwrlock+0x168> // b.any
d3a0: 88137dc5 stxr w19, w5, [x14]
Thanks,
Andrew Pinski
>
> 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],
