From: "Kewen.Lin" <linkw@linux.ibm.com>
To: GCC Patches <gcc-patches@gcc.gnu.org>
Cc: Richard Biener <richard.guenther@gmail.com>,
Richard Sandiford <richard.sandiford@arm.com>,
Jeff Law <jlaw@ventanamicro.com>,
Vladimir Makarov <vmakarov@redhat.com>,
Alexander Monakov <amonakov@ispras.ru>,
zhroma@ispras.ru, abel@ispras.ru,
Segher Boessenkool <segher@kernel.crashing.org>,
Peter Bergner <bergner@linux.ibm.com>,
Michael Meissner <meissner@linux.ibm.com>
Subject: PING^1 [PATCH v3] sched: Change no_real_insns_p to no_real_nondebug_insns_p [PR108273]
Date: Wed, 8 Nov 2023 10:49:01 +0800 [thread overview]
Message-ID: <f8c59aa8-5b58-b8dd-86b0-8d825f753d6f@linux.ibm.com> (raw)
In-Reply-To: <85b4098e-a72f-d013-ff17-8097971f71ba@linux.ibm.com>
Hi,
Gentle ping this:
https://gcc.gnu.org/pipermail/gcc-patches/2023-October/634201.html
BR,
Kewen
on 2023/10/25 10:45, Kewen.Lin wrote:
> Hi,
>
> This is almost a repost for v2 which was posted at[1] in March
> excepting for:
> 1) rebased from r14-4810 which is relatively up-to-date,
> some conflicts on "int to bool" return type change have
> been resolved;
> 2) adjust commit log a bit;
> 3) fix misspelled "articial" with "artificial" somewhere;
>
> --
> *v2 comments*:
>
> By addressing Alexander's comments, against v1 this
> patch v2 mainly:
>
> - Rename no_real_insns_p to no_real_nondebug_insns_p;
> - Introduce enum rgn_bb_deps_free_action for three
> kinds of actions to free deps;
> - Change function free_deps_for_bb_no_real_insns_p to
> resolve_forw_deps which only focuses on forward deps;
> - Extend the handlings to cover dbg-cnt sched_block,
> add one test case for it;
> - Move free_trg_info call in schedule_region to an
> appropriate place.
>
> One thing I'm not sure about is the change in function
> sched_rgn_local_finish, currently the invocation to
> sched_rgn_local_free is guarded with !sel_sched_p (),
> so I just follow it, but the initialization of those
> structures (in sched_rgn_local_init) isn't guarded
> with !sel_sched_p (), it looks odd.
>
> --
>
> As PR108273 shows, when there is one block which only has
> NOTE_P and LABEL_P insns at non-debug mode while has some
> extra DEBUG_INSN_P insns at debug mode, after scheduling
> it, the DFA states would be different between debug mode
> and non-debug mode. Since at non-debug mode, the block
> meets no_real_insns_p, it gets skipped; while at debug
> mode, it gets scheduled, even it only has NOTE_P, LABEL_P
> and DEBUG_INSN_P, the call of function advance_one_cycle
> will change the DFA state. PR108519 also shows this issue
> can be exposed by some scheduler changes.
>
> This patch is to change function no_real_insns_p to
> function no_real_nondebug_insns_p by taking debug insn into
> account, which make us not try to schedule for the block
> having only NOTE_P, LABEL_P and DEBUG_INSN_P insns,
> resulting in consistent DFA states between non-debug and
> debug mode.
>
> Changing no_real_insns_p to no_real_nondebug_insns_p caused
> ICE when doing free_block_dependencies, the root cause is
> that we create dependencies for debug insns, those
> dependencies are expected to be resolved during scheduling
> insns, but they get skipped after this change.
> By checking the code, it looks it's reasonable to skip to
> compute block dependences for no_real_nondebug_insns_p
> blocks. There is also another issue, which gets exposed
> in SPEC2017 bmks build at option -O2 -g, is that we could
> skip to schedule some block, which already gets dependency
> graph built so has dependencies computed and rgn_n_insns
> accumulated, then the later verification on if the graph
> becomes exhausted by scheduling would fail as follow:
>
> /* Sanity check: verify that all region insns were
> scheduled. */
> gcc_assert (sched_rgn_n_insns == rgn_n_insns);
>
> , and also some forward deps aren't resovled.
>
> As Alexander pointed out, the current debug count handling
> also suffers the similar issue, so this patch handles these
> two cases together: one is for some block gets skipped by
> !dbg_cnt (sched_block), the other is for some block which
> is not no_real_nondebug_insns_p initially but becomes
> no_real_nondebug_insns_p due to speculative scheduling.
>
> This patch can be bootstrapped and regress-tested on
> x86_64-redhat-linux, aarch64-linux-gnu and
> powerpc64{,le}-linux-gnu.
>
> I also verified this patch can pass SPEC2017 both intrate
> and fprate bmks building at -g -O2/-O3.
>
> Any thoughts? Is it ok for trunk?
>
> [1] v2: https://gcc.gnu.org/pipermail/gcc-patches/2023-March/614818.html
> [2] v1: https://gcc.gnu.org/pipermail/gcc-patches/2023-March/614224.html
>
> BR,
> Kewen
> -----
> PR rtl-optimization/108273
>
> gcc/ChangeLog:
>
> * haifa-sched.cc (no_real_insns_p): Rename to ...
> (no_real_nondebug_insns_p): ... this, and consider DEBUG_INSN_P insn.
> * sched-ebb.cc (schedule_ebb): Replace no_real_insns_p with
> no_real_nondebug_insns_p.
> * sched-int.h (no_real_insns_p): Rename to ...
> (no_real_nondebug_insns_p): ... this.
> * sched-rgn.cc (enum rgn_bb_deps_free_action): New enum.
> (bb_deps_free_actions): New static variable.
> (compute_block_dependences): Skip for no_real_nondebug_insns_p.
> (resolve_forw_deps): New function.
> (free_block_dependencies): Check bb_deps_free_actions and call
> function resolve_forw_deps for RGN_BB_DEPS_FREE_ARTIFICIAL.
> (compute_priorities): Replace no_real_insns_p with
> no_real_nondebug_insns_p.
> (schedule_region): Replace no_real_insns_p with
> no_real_nondebug_insns_p, set RGN_BB_DEPS_FREE_ARTIFICIAL if the block
> get dependencies computed before but skipped now, fix up count
> sched_rgn_n_insns for it too. Call free_trg_info when the block
> gets scheduled, and move sched_rgn_local_finish after the loop
> of free_block_dependencies loop.
> (sched_rgn_local_init): Allocate and compute bb_deps_free_actions.
> (sched_rgn_local_finish): Free bb_deps_free_actions.
> * sel-sched.cc (sel_region_target_finish): Replace no_real_insns_p with
> no_real_nondebug_insns_p.
>
> gcc/testsuite/ChangeLog:
>
> * gcc.target/powerpc/pr108273.c: New test.
> ---
> gcc/haifa-sched.cc | 9 +-
> gcc/sched-ebb.cc | 2 +-
> gcc/sched-int.h | 2 +-
> gcc/sched-rgn.cc | 148 +++++++++++++++-----
> gcc/sel-sched.cc | 3 +-
> gcc/testsuite/gcc.target/powerpc/pr108273.c | 26 ++++
> 6 files changed, 150 insertions(+), 40 deletions(-)
> create mode 100644 gcc/testsuite/gcc.target/powerpc/pr108273.c
>
> diff --git a/gcc/haifa-sched.cc b/gcc/haifa-sched.cc
> index 8e8add709b3..30cc90ec49f 100644
> --- a/gcc/haifa-sched.cc
> +++ b/gcc/haifa-sched.cc
> @@ -5033,14 +5033,17 @@ get_ebb_head_tail (basic_block beg, basic_block end,
> *tailp = end_tail;
> }
>
> -/* Return true if there are no real insns in the range [ HEAD, TAIL ]. */
> +/* Return true if there are no real nondebug insns in the range
> + [ HEAD, TAIL ]. */
>
> bool
> -no_real_insns_p (const rtx_insn *head, const rtx_insn *tail)
> +no_real_nondebug_insns_p (const rtx_insn *head, const rtx_insn *tail)
> {
> while (head != NEXT_INSN (tail))
> {
> - if (!NOTE_P (head) && !LABEL_P (head))
> + if (!NOTE_P (head)
> + && !LABEL_P (head)
> + && !DEBUG_INSN_P (head))
> return false;
> head = NEXT_INSN (head);
> }
> diff --git a/gcc/sched-ebb.cc b/gcc/sched-ebb.cc
> index 110fcdbca4d..03d96290a7c 100644
> --- a/gcc/sched-ebb.cc
> +++ b/gcc/sched-ebb.cc
> @@ -491,7 +491,7 @@ schedule_ebb (rtx_insn *head, rtx_insn *tail, bool modulo_scheduling)
> first_bb = BLOCK_FOR_INSN (head);
> last_bb = BLOCK_FOR_INSN (tail);
>
> - if (no_real_insns_p (head, tail))
> + if (no_real_nondebug_insns_p (head, tail))
> return BLOCK_FOR_INSN (tail);
>
> gcc_assert (INSN_P (head) && INSN_P (tail));
> diff --git a/gcc/sched-int.h b/gcc/sched-int.h
> index 64a2f0bcff9..adca494ade5 100644
> --- a/gcc/sched-int.h
> +++ b/gcc/sched-int.h
> @@ -1397,7 +1397,7 @@ extern void free_global_sched_pressure_data (void);
> extern int haifa_classify_insn (const_rtx);
> extern void get_ebb_head_tail (basic_block, basic_block,
> rtx_insn **, rtx_insn **);
> -extern bool no_real_insns_p (const rtx_insn *, const rtx_insn *);
> +extern bool no_real_nondebug_insns_p (const rtx_insn *, const rtx_insn *);
>
> extern int insn_sched_cost (rtx_insn *);
> extern int dep_cost_1 (dep_t, dw_t);
> diff --git a/gcc/sched-rgn.cc b/gcc/sched-rgn.cc
> index e5964f54ead..2549e834aa8 100644
> --- a/gcc/sched-rgn.cc
> +++ b/gcc/sched-rgn.cc
> @@ -213,6 +213,22 @@ static int rgn_nr_edges;
> /* Array of size rgn_nr_edges. */
> static edge *rgn_edges;
>
> +/* Possible actions for dependencies freeing. */
> +enum rgn_bb_deps_free_action
> +{
> + /* This block doesn't get dependencies computed so don't need to free. */
> + RGN_BB_DEPS_FREE_NO,
> + /* This block gets scheduled normally so free dependencies as usual. */
> + RGN_BB_DEPS_FREE_NORMAL,
> + /* This block gets skipped in scheduling but has dependencies computed early,
> + need to free the forward list artificially. */
> + RGN_BB_DEPS_FREE_ARTIFICIAL
> +};
> +
> +/* For basic block i, bb_deps_free_actions[i] indicates which action needs
> + to be taken for freeing its dependencies. */
> +static enum rgn_bb_deps_free_action *bb_deps_free_actions;
> +
> /* Mapping from each edge in the graph to its number in the rgn. */
> #define EDGE_TO_BIT(edge) ((int)(size_t)(edge)->aux)
> #define SET_EDGE_TO_BIT(edge,nr) ((edge)->aux = (void *)(size_t)(nr))
> @@ -2735,6 +2751,15 @@ compute_block_dependences (int bb)
> gcc_assert (EBB_FIRST_BB (bb) == EBB_LAST_BB (bb));
> get_ebb_head_tail (EBB_FIRST_BB (bb), EBB_LAST_BB (bb), &head, &tail);
>
> + /* Don't compute block dependences if there are no real nondebug insns. */
> + if (no_real_nondebug_insns_p (head, tail))
> + {
> + if (current_nr_blocks > 1)
> + propagate_deps (bb, &tmp_deps);
> + free_deps (&tmp_deps);
> + return;
> + }
> +
> sched_analyze (&tmp_deps, head, tail);
>
> add_branch_dependences (head, tail);
> @@ -2749,6 +2774,24 @@ compute_block_dependences (int bb)
> targetm.sched.dependencies_evaluation_hook (head, tail);
> }
>
> +/* Artificially resolve forward dependencies for instructions HEAD to TAIL. */
> +
> +static void
> +resolve_forw_deps (rtx_insn *head, rtx_insn *tail)
> +{
> + rtx_insn *insn;
> + rtx_insn *next_tail = NEXT_INSN (tail);
> + sd_iterator_def sd_it;
> + dep_t dep;
> +
> + /* There could be some insns which get skipped in scheduling but we compute
> + dependencies for them previously, so make them resolved. */
> + for (insn = head; insn != next_tail; insn = NEXT_INSN (insn))
> + for (sd_it = sd_iterator_start (insn, SD_LIST_FORW);
> + sd_iterator_cond (&sd_it, &dep);)
> + sd_resolve_dep (sd_it);
> +}
> +
> /* Free dependencies of instructions inside BB. */
> static void
> free_block_dependencies (int bb)
> @@ -2758,9 +2801,12 @@ free_block_dependencies (int bb)
>
> get_ebb_head_tail (EBB_FIRST_BB (bb), EBB_LAST_BB (bb), &head, &tail);
>
> - if (no_real_insns_p (head, tail))
> + if (bb_deps_free_actions[bb] == RGN_BB_DEPS_FREE_NO)
> return;
>
> + if (bb_deps_free_actions[bb] == RGN_BB_DEPS_FREE_ARTIFICIAL)
> + resolve_forw_deps (head, tail);
> +
> sched_free_deps (head, tail, true);
> }
>
> @@ -3024,7 +3070,7 @@ compute_priorities (void)
> gcc_assert (EBB_FIRST_BB (bb) == EBB_LAST_BB (bb));
> get_ebb_head_tail (EBB_FIRST_BB (bb), EBB_LAST_BB (bb), &head, &tail);
>
> - if (no_real_insns_p (head, tail))
> + if (no_real_nondebug_insns_p (head, tail))
> continue;
>
> rgn_n_insns += set_priorities (head, tail);
> @@ -3158,7 +3204,7 @@ schedule_region (int rgn)
>
> get_ebb_head_tail (first_bb, last_bb, &head, &tail);
>
> - if (no_real_insns_p (head, tail))
> + if (no_real_nondebug_insns_p (head, tail))
> {
> gcc_assert (first_bb == last_bb);
> continue;
> @@ -3178,44 +3224,62 @@ schedule_region (int rgn)
>
> get_ebb_head_tail (first_bb, last_bb, &head, &tail);
>
> - if (no_real_insns_p (head, tail))
> + if (no_real_nondebug_insns_p (head, tail))
> {
> gcc_assert (first_bb == last_bb);
> save_state_for_fallthru_edge (last_bb, bb_state[first_bb->index]);
> - continue;
> +
> + if (bb_deps_free_actions[bb] == RGN_BB_DEPS_FREE_NO)
> + continue;
> +
> + /* As it's not no_real_nondebug_insns_p initially, then it has some
> + dependencies computed so free it artificially. */
> + bb_deps_free_actions[bb] = RGN_BB_DEPS_FREE_ARTIFICIAL;
> }
> + else
> + {
> + current_sched_info->prev_head = PREV_INSN (head);
> + current_sched_info->next_tail = NEXT_INSN (tail);
>
> - current_sched_info->prev_head = PREV_INSN (head);
> - current_sched_info->next_tail = NEXT_INSN (tail);
> + remove_notes (head, tail);
>
> - remove_notes (head, tail);
> + unlink_bb_notes (first_bb, last_bb);
>
> - unlink_bb_notes (first_bb, last_bb);
> + target_bb = bb;
>
> - target_bb = bb;
> + gcc_assert (flag_schedule_interblock || current_nr_blocks == 1);
> + current_sched_info->queue_must_finish_empty = current_nr_blocks == 1;
>
> - gcc_assert (flag_schedule_interblock || current_nr_blocks == 1);
> - current_sched_info->queue_must_finish_empty = current_nr_blocks == 1;
> + curr_bb = first_bb;
> + if (dbg_cnt (sched_block))
> + {
> + int saved_last_basic_block = last_basic_block_for_fn (cfun);
>
> - curr_bb = first_bb;
> - if (dbg_cnt (sched_block))
> - {
> - int saved_last_basic_block = last_basic_block_for_fn (cfun);
> + schedule_block (&curr_bb, bb_state[first_bb->index]);
> + gcc_assert (EBB_FIRST_BB (bb) == first_bb);
> + sched_rgn_n_insns += sched_n_insns;
> + realloc_bb_state_array (saved_last_basic_block);
> + save_state_for_fallthru_edge (last_bb, curr_state);
>
> - schedule_block (&curr_bb, bb_state[first_bb->index]);
> - gcc_assert (EBB_FIRST_BB (bb) == first_bb);
> - sched_rgn_n_insns += sched_n_insns;
> - realloc_bb_state_array (saved_last_basic_block);
> - save_state_for_fallthru_edge (last_bb, curr_state);
> - }
> - else
> - {
> - sched_rgn_n_insns += rgn_n_insns;
> - }
> + /* Clean up. */
> + if (current_nr_blocks > 1)
> + free_trg_info ();
> + }
> + else
> + bb_deps_free_actions[bb] = RGN_BB_DEPS_FREE_ARTIFICIAL;
> + }
>
> - /* Clean up. */
> - if (current_nr_blocks > 1)
> - free_trg_info ();
> + /* We have counted this block when computing rgn_n_insns
> + previously, so need to fix up sched_rgn_n_insns now. */
> + if (bb_deps_free_actions[bb] == RGN_BB_DEPS_FREE_ARTIFICIAL)
> + {
> + while (head != NEXT_INSN (tail))
> + {
> + if (INSN_P (head))
> + sched_rgn_n_insns++;
> + head = NEXT_INSN (head);
> + }
> + }
> }
>
> /* Sanity check: verify that all region insns were scheduled. */
> @@ -3223,13 +3287,13 @@ schedule_region (int rgn)
>
> sched_finish_ready_list ();
>
> - /* Done with this region. */
> - sched_rgn_local_finish ();
> -
> /* Free dependencies. */
> for (bb = 0; bb < current_nr_blocks; ++bb)
> free_block_dependencies (bb);
>
> + /* Done with this region. */
> + sched_rgn_local_finish ();
> +
> gcc_assert (haifa_recovery_bb_ever_added_p
> || deps_pools_are_empty_p ());
> }
> @@ -3450,6 +3514,19 @@ sched_rgn_local_init (int rgn)
> e->aux = NULL;
> }
> }
> +
> + /* Initialize bb_deps_free_actions. */
> + bb_deps_free_actions
> + = XNEWVEC (enum rgn_bb_deps_free_action, current_nr_blocks);
> + for (bb = 0; bb < current_nr_blocks; bb++)
> + {
> + rtx_insn *head, *tail;
> + get_ebb_head_tail (EBB_FIRST_BB (bb), EBB_LAST_BB (bb), &head, &tail);
> + if (no_real_nondebug_insns_p (head, tail))
> + bb_deps_free_actions[bb] = RGN_BB_DEPS_FREE_NO;
> + else
> + bb_deps_free_actions[bb] = RGN_BB_DEPS_FREE_NORMAL;
> + }
> }
>
> /* Free data computed for the finished region. */
> @@ -3467,9 +3544,12 @@ sched_rgn_local_free (void)
> void
> sched_rgn_local_finish (void)
> {
> - if (current_nr_blocks > 1 && !sel_sched_p ())
> + if (!sel_sched_p ())
> {
> - sched_rgn_local_free ();
> + if (current_nr_blocks > 1)
> + sched_rgn_local_free ();
> +
> + free (bb_deps_free_actions);
> }
> }
>
> diff --git a/gcc/sel-sched.cc b/gcc/sel-sched.cc
> index 1925f4a9461..8310c892e13 100644
> --- a/gcc/sel-sched.cc
> +++ b/gcc/sel-sched.cc
> @@ -7213,7 +7213,8 @@ sel_region_target_finish (bool reset_sched_cycles_p)
>
> find_ebb_boundaries (EBB_FIRST_BB (i), scheduled_blocks);
>
> - if (no_real_insns_p (current_sched_info->head, current_sched_info->tail))
> + if (no_real_nondebug_insns_p (current_sched_info->head,
> + current_sched_info->tail))
> continue;
>
> if (reset_sched_cycles_p)
> diff --git a/gcc/testsuite/gcc.target/powerpc/pr108273.c b/gcc/testsuite/gcc.target/powerpc/pr108273.c
> new file mode 100644
> index 00000000000..937224eaa69
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/powerpc/pr108273.c
> @@ -0,0 +1,26 @@
> +/* { dg-options "-O2 -fdbg-cnt=sched_block:1" } */
> +/* { dg-prune-output {\*\*\*dbgcnt:.*limit.*reached} } */
> +
> +/* Verify there is no ICE. */
> +
> +int a, b, c, e, f;
> +float d;
> +
> +void
> +g ()
> +{
> + float h, i[1];
> + for (; f;)
> + if (c)
> + {
> + d *e;
> + if (b)
> + {
> + float *j = i;
> + j[0] += 0;
> + }
> + h += d;
> + }
> + if (h)
> + a = i[0];
> +}
> --
> 2.39.1
next prev parent reply other threads:[~2023-11-08 2:49 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-25 2:45 Kewen.Lin
2023-11-08 2:49 ` Kewen.Lin [this message]
2023-11-08 9:45 ` PING^1 " Richard Sandiford
2023-11-09 9:10 ` Maxim Kuvyrkov
2023-11-09 17:40 ` Alexander Monakov
2023-11-10 1:57 ` Kewen.Lin
2023-11-10 3:49 ` Jeff Law
2023-11-10 11:25 ` Alexander Monakov
2023-11-10 13:32 ` Richard Biener
2023-11-10 14:18 ` Alexander Monakov
2023-11-10 14:20 ` Richard Biener
2023-11-10 14:41 ` Alexander Monakov
2023-11-15 9:12 ` Kewen.Lin
2023-11-15 9:43 ` Alexander Monakov
2023-11-17 9:03 ` Kewen.Lin
2023-11-17 10:13 ` Richard Biener
2023-11-17 12:55 ` Alexander Monakov
2023-11-22 9:30 ` Kewen.Lin
2023-11-22 10:25 ` Richard Biener
2023-11-23 2:36 ` Kewen.Lin
2023-11-23 8:20 ` Richard Biener
2023-11-23 9:09 ` Kewen.Lin
2023-12-12 7:02 ` [PATCH draft v2] sched: Don't skip empty block in scheduling [PR108273] Kewen.Lin
2023-11-10 3:49 ` PING^1 [PATCH v3] sched: Change no_real_insns_p to no_real_nondebug_insns_p [PR108273] Jeff Law
2023-11-15 9:01 ` [PATCH] sched: Remove debug counter sched_block Kewen.Lin
2023-12-12 6:17 ` PING^1 " Kewen.Lin
2023-12-20 20:43 ` Jeff Law
2023-12-21 5:46 ` Kewen.Lin
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