| Message ID | Zao7Okg+FkinTG6T@arm.com |
|---|---|
| State | New |
| Headers | show |
| Series | [1/3] rtl-ssa: Provide easier access to debug uses [PR113089] | expand |
Alex Coplan <alex.coplan@arm.com> writes: > While working on PR113089, I realised we where missing code to re-parent > trailing nondebug uses of the base register in the case of cancelling > writeback in the load/store pair pass. This patch fixes that. > > Bootstrapped/regtested as a series on aarch64-linux-gnu (with/without > the pass enabled), OK for trunk? > > Thanks, > Alex > > gcc/ChangeLog: > > PR target/113089 > * config/aarch64/aarch64-ldp-fusion.cc (ldp_bb_info::fuse_pair): > Update trailing nondebug uses of the base register in the case > of cancelling writeback. OK, thanks. I suppose in future it would be good to have a way of stitching together the use lists of two consecutive defs, since that should be possible in constant time. But that's just a possible future enhancement. The update as it stands should still be linear, since all updated uses would come before the next writeback candidate involving the same base register. Richard > --- > gcc/config/aarch64/aarch64-ldp-fusion.cc | 24 ++++++++++++++++++++++++ > 1 file changed, 24 insertions(+) > > diff --git a/gcc/config/aarch64/aarch64-ldp-fusion.cc b/gcc/config/aarch64/aarch64-ldp-fusion.cc > index 70b75c668ce..4d7fd72c6b1 100644 > --- a/gcc/config/aarch64/aarch64-ldp-fusion.cc > +++ b/gcc/config/aarch64/aarch64-ldp-fusion.cc > @@ -1693,6 +1693,30 @@ ldp_bb_info::fuse_pair (bool load_p, > > if (trailing_add) > changes.safe_push (make_delete (trailing_add)); > + else if ((writeback & 2) && !writeback_effect) > + { > + // The second insn initially had writeback but now the pair does not, > + // need to update any nondebug uses of the base register def in the > + // second insn. We'll take care of debug uses later. > + auto def = find_access (insns[1]->defs (), base_regno); > + gcc_assert (def); > + auto set = dyn_cast<set_info *> (def); > + if (set && set->has_nondebug_uses ()) > + { > + auto orig_use = find_access (insns[0]->uses (), base_regno); > + for (auto use : set->nondebug_insn_uses ()) > + { > + auto change = make_change (use->insn ()); > + change->new_uses = check_remove_regno_access (attempt, > + change->new_uses, > + base_regno); > + change->new_uses = insert_access (attempt, > + orig_use, > + change->new_uses); > + changes.safe_push (change); > + } > + } > + } > > auto is_changing = insn_is_changing (changes); > for (unsigned i = 0; i < changes.length (); i++)
diff --git a/gcc/config/aarch64/aarch64-ldp-fusion.cc b/gcc/config/aarch64/aarch64-ldp-fusion.cc index 70b75c668ce..4d7fd72c6b1 100644 --- a/gcc/config/aarch64/aarch64-ldp-fusion.cc +++ b/gcc/config/aarch64/aarch64-ldp-fusion.cc @@ -1693,6 +1693,30 @@ ldp_bb_info::fuse_pair (bool load_p, if (trailing_add) changes.safe_push (make_delete (trailing_add)); + else if ((writeback & 2) && !writeback_effect) + { + // The second insn initially had writeback but now the pair does not, + // need to update any nondebug uses of the base register def in the + // second insn. We'll take care of debug uses later. + auto def = find_access (insns[1]->defs (), base_regno); + gcc_assert (def); + auto set = dyn_cast<set_info *> (def); + if (set && set->has_nondebug_uses ()) + { + auto orig_use = find_access (insns[0]->uses (), base_regno); + for (auto use : set->nondebug_insn_uses ()) + { + auto change = make_change (use->insn ()); + change->new_uses = check_remove_regno_access (attempt, + change->new_uses, + base_regno); + change->new_uses = insert_access (attempt, + orig_use, + change->new_uses); + changes.safe_push (change); + } + } + } auto is_changing = insn_is_changing (changes); for (unsigned i = 0; i < changes.length (); i++)