On Mon, Nov 27, 2023 at 3:51 PM Jakub Jelinek <ja...@redhat.com> wrote:
>
> On Mon, Nov 27, 2023 at 09:52:14PM +0100, Jakub Jelinek wrote:
> > On Mon, Oct 16, 2023 at 01:11:01PM -0600, Jeff Law wrote:
> > > > gcc/ChangeLog:
> > > >
> > > > * Makefile.in: Add fold-mem-offsets.o.
> > > > * passes.def: Schedule a new pass.
> > > > * tree-pass.h (make_pass_fold_mem_offsets): Declare.
> > > > * common.opt: New options.
> > > > * doc/invoke.texi: Document new option.
> > > > * fold-mem-offsets.cc: New file.
> > > >
> > > > gcc/testsuite/ChangeLog:
> > > >
> > > > * gcc.target/riscv/fold-mem-offsets-1.c: New test.
> > > > * gcc.target/riscv/fold-mem-offsets-2.c: New test.
> > > > * gcc.target/riscv/fold-mem-offsets-3.c: New test.
> > > Thanks, I've pushed this to the trunk.
> >
> > This breaks profiledbootstrap on powerpc64le-linux.
> > >From what I can see, the pass works one basic block at a time and
> > will punt on any non-DEBUG_INSN uses outside of the current block
> > (I believe because of the
> > /* This use affects instructions outside of CAN_FOLD_INSNS. */
> > if (!bitmap_bit_p (&can_fold_insns, INSN_UID (use)))
> > return 0;
> > test and can_fold_insns only set in do_analysis (when processing insns in
> > current bb, cleared at the end) or results of get_single_def_in_bb
> > (which are checked to be in the same bb).
> > But, while get_single_def_in_bb checks for
> > if (DF_INSN_LUID (def) > DF_INSN_LUID (insn))
> > return NULL;
> > (OT, why not DF_INSN_INFO_LUID (DF_REF_INSN_INFO (ref_chain->ref))
> > instead of DF_INSN_LUID (def), then it doesn't need to look up
> > DF_INSN_INFO_GET (def)?), nothing when walking all uses of def does such
> > luid check.
> > The basic block in the PR in question has:
> > ...
> > (insn 212 210 215 25 (set (mem/f:DI (reg/v/f:DI 10 10 [orig:152 last_viable
> > ] [152]) [2 *last_viable_336+0 S8 A64])
> > (reg/f:DI 9 9 [orig:155 _342 ] [155])) "pr111601.ii":50:17 683
> > {*movdi_internal64}
> > (expr_list:REG_DEAD (reg/v/f:DI 10 10 [orig:152 last_viable ] [152])
> > (nil)))
> > (insn 215 212 484 25 (set (reg:DI 5 5 [226])
> > (const_int 0 [0])) "pr111601.ii":52:12 683 {*movdi_internal64}
> > (expr_list:REG_EQUIV (const_int 0 [0])
> > (nil)))
> > (insn 484 215 218 25 (set (reg/v/f:DI 10 10 [orig:152 last_viable ] [152])
> > (reg/f:DI 9 9 [orig:155 _342 ] [155])) "pr111601.ii":52:12 683
> > {*movdi_internal64}
> > (nil))
> > ...
> > (insn 564 214 216 25 (set (reg/v/f:DI 10 10 [orig:152 last_viable ] [152])
> > (plus:DI (reg/v/f:DI 10 10 [orig:152 last_viable ] [152])
> > (const_int 96 [0x60]))) "pr111601.ii":52:12 66 {*adddi3}
> > (nil))
> > (insn 216 564 219 25 (set (mem/f:DI (reg/v/f:DI 10 10 [orig:152 last_viable
> > ] [152]) [2 _343->next+0 S8 A64])
> > (reg:DI 5 5 [226])) "pr111601.ii":52:12 683 {*movdi_internal64}
> > (expr_list:REG_DEAD (reg:DI 5 5 [226])
> > (nil)))
> > ...
> > and when asking for all uses of %r10 from def 564, it will see uses
> > in 216 and 212; the former is after the += 96 addition and gets changed
> > to load from %r10+96 with the addition being dropped, but there is
> > the other store which is a use across the backedge and when reached
> > from other edges certainly doesn't have the + 96 addition anywhere,
> > so the pass doesn't actually change that location.
> >
> > Haven't bootstrapped/regtested this yet, will start momentarily,
> > posting here just in case I'm missing something important.
>
> That version failed bootstrap because DF_INSN_LUID is signed int, not
> unsigned.
>
> Here is what so far passed on powerpc64le-linux
> ../configure --enable-languages=c,c++ --enable-checking=yes,rtl,extra
> --disable-libsanitizer --with-long-double-128
> make -j160 profiledbootstrap
> which has been failing for more than a month now.
>
> I've noticed a couple of small formatting issues and fixed them too,
> doing normal {powerpc64le,x86_64,i686}-linux bootstraps/regtests:
>
> 2023-11-27 Jakub Jelinek <ja...@redhat.com>
>
> PR bootstrap/111601
> * fold-mem-offsets.cc (fold_offsets): Punt if use appears before
> def in the basic block.
> (get_single_def_in_bb, get_uses): Formatting fixes.
> (fold_offsets_1, pass_fold_mem_offsets::execute): Comment formatting
> fixes.
>
> * g++.dg/opt/pr111601.C: New test.
>
> --- gcc/fold-mem-offsets.cc.jj 2023-11-02 07:49:17.060865772 +0100
> +++ gcc/fold-mem-offsets.cc 2023-11-27 22:47:21.128591332 +0100
> @@ -154,7 +154,7 @@ static int stats_fold_count;
> The definition is desired for REG used in INSN.
> Return the definition insn or NULL if there's no definition with
> the desired criteria. */
> -static rtx_insn*
> +static rtx_insn *
> get_single_def_in_bb (rtx_insn *insn, rtx reg)
> {
> df_ref use;
> @@ -205,7 +205,7 @@ get_single_def_in_bb (rtx_insn *insn, rt
> /* Get all uses of REG which is set in INSN. Return the use list or NULL if
> a
> use is missing / irregular. If SUCCESS is not NULL then set it to false
> if
> there are missing / irregular uses and true otherwise. */
> -static struct df_link*
> +static struct df_link *
Since you are making style changes here, it might make sense to remove
the struct keyword too since this is C++ code after all.
Thanks,
Andrew Pinski
> get_uses (rtx_insn *insn, rtx reg, bool *success)
> {
> df_ref def;
> @@ -255,8 +255,7 @@ fold_offsets (rtx_insn *insn, rtx reg, b
>
> If DO_RECURSION is true and ANALYZE is false then offset that would
> result
> from folding is computed and is returned through the pointer OFFSET_OUT.
> - The instructions that can be folded are recorded in FOLDABLE_INSNS.
> -*/
> + The instructions that can be folded are recorded in FOLDABLE_INSNS. */
> static bool
> fold_offsets_1 (rtx_insn *insn, bool analyze, bool do_recursion,
> HOST_WIDE_INT *offset_out, bitmap foldable_insns)
> @@ -511,6 +510,7 @@ fold_offsets (rtx_insn *insn, rtx reg, b
> if (!success)
> return 0;
>
> + int luid = DF_INSN_LUID (def);
> for (ref_link = uses; ref_link; ref_link = ref_link->next)
> {
> rtx_insn *use = DF_REF_INSN (ref_link->ref);
> @@ -534,6 +534,11 @@ fold_offsets (rtx_insn *insn, rtx reg, b
> if (use_set && MEM_P (SET_DEST (use_set))
> && reg_mentioned_p (dest, SET_SRC (use_set)))
> return 0;
> +
> + /* Punt if use appears before def in the basic block. See
> + PR111601. */
> + if (DF_INSN_LUID (use) < luid)
> + return 0;
> }
>
> bitmap_set_bit (&can_fold_insns, INSN_UID (def));
> @@ -846,8 +851,8 @@ pass_fold_mem_offsets::execute (function
> FOR_ALL_BB_FN (bb, fn)
> {
> /* There is a conflict between this pass and RISCV's shorten-memrefs
> - pass. For now disable folding if optimizing for size because
> - otherwise this cancels the effects of shorten-memrefs. */
> + pass. For now disable folding if optimizing for size because
> + otherwise this cancels the effects of shorten-memrefs. */
> if (optimize_bb_for_size_p (bb))
> continue;
>
> --- gcc/testsuite/g++.dg/opt/pr111601.C.jj 2023-11-27 21:33:12.605006881
> +0100
> +++ gcc/testsuite/g++.dg/opt/pr111601.C 2023-11-27 21:34:47.267678510 +0100
> @@ -0,0 +1,86 @@
> +// PR bootstrap/111601
> +// { dg-do run { target c++11 } }
> +// { dg-options "-O2 -fno-exceptions -fno-rtti -fprofile-generate" }
> +// { dg-require-profiling "-fprofile-generate" }
> +// { dg-final { cleanup-coverage-files } }
> +
> +struct tree_base
> +{
> + int code:16;
> +};
> +struct saved_scope
> +{
> + void *pad[14];
> + int x_processing_template_decl;
> +};
> +struct saved_scope *scope_chain;
> +struct z_candidate
> +{
> + tree_base *fn;
> + void *pad[11];
> + z_candidate *next;
> + int viable;
> + int flags;
> +};
> +
> +__attribute__((noipa)) struct z_candidate *
> +splice_viable (struct z_candidate *cands, bool strict_p, bool *any_viable_p)
> +{
> + struct z_candidate *viable;
> + struct z_candidate **last_viable;
> + struct z_candidate **cand;
> + bool found_strictly_viable = false;
> + if (scope_chain->x_processing_template_decl)
> + strict_p = true;
> + viable = (z_candidate *) 0;
> + last_viable = &viable;
> + *any_viable_p = false;
> + cand = &cands;
> + while (*cand)
> + {
> + struct z_candidate *c = *cand;
> + if (!strict_p && (c->viable == 1 || ((int) (c->fn)->code) == 273))
> + {
> + strict_p = true;
> + if (viable && !found_strictly_viable)
> + {
> + *any_viable_p = false;
> + *last_viable = cands;
> + cands = viable;
> + viable = (z_candidate *) 0;
> + last_viable = &viable;
> + }
> + }
> + if (strict_p ? c->viable == 1 : c->viable)
> + {
> + *last_viable = c;
> + *cand = c->next;
> + c->next = (z_candidate *) 0;
> + last_viable = &c->next;
> + *any_viable_p = true;
> + if (c->viable == 1)
> + found_strictly_viable = true;
> + }
> + else
> + cand = &c->next;
> + }
> + return viable ? viable : cands;
> +}
> +
> +int
> +main ()
> +{
> + saved_scope s{};
> + scope_chain = &s;
> + z_candidate z[4] = {};
> + z[0].next = &z[1];
> + z[1].viable = 1;
> + z[1].next = &z[2];
> + z[2].viable = 1;
> + z[2].next = &z[3];
> + bool b;
> + z_candidate *c = splice_viable (&z[0], true, &b);
> + if (c != &z[1] || z[1].next != &z[2] || z[2].next)
> + __builtin_abort ();
> + return 0;
> +}
>
>
> Jakub
>
