Hi Honza,
It seems this commit caused gcc bootstrap failure on aarch64 as below,
Comparing stages 2 and 3
warning: gcc/cc1obj-checksum.o differs
Bootstrap comparison failure!
gcc/dwarf2out.o differs
gcc/var-tracking.o differs
gcc/aarch64.o differs
make[2]: *** [compare] Error 1
Do you know the reason? I'm not sure if you have an aarch64 machine to try. Can
it be fixed?
Thanks,
-Jiangning
> -----Original Message-----
> From: gcc-patches-ow...@gcc.gnu.org <gcc-patches-ow...@gcc.gnu.org>
> On Behalf Of Jan Hubicka
> Sent: Sunday, July 14, 2019 8:03 PM
> To: gcc-patches@gcc.gnu.org
> Subject: Remove array_index inliner hint
>
> Hi,
> array_index hint marks functions contains an array reference that is indexed
> by value that will become constant after inlining.
> This hint is later used by ipa-inline in rather agressive way updating inline-
> insns-auto to inline-insns-single for such functions. While tuning -finline-
> functions for -O2 I have noticed that this leads to 30% code size growth of
> SPEC versions of GCC. This is because all predicates like register_operand
> contains such array references based on mode parameter and this makes
> GCC to conclude about agressively inlining them all which bloats
> insn-* a lot.
>
> This hint was quite early experiment with propagating additional stuff
> through inliner. I think it is better to actualy account the instructions
> which
> will be generated for array indexing rather then handling this specially.
>
> This patch makes us to accound 1 instruction for every non-constant array
> access. This is still probably making inliner overly optimistic about
> inlining
> benefits since these accesses will later be CSEed, but it kills bit of magic
> and
> makes things more robust.
>
> This will make inliner notice that function will simplify and give it higher
> priority for inlining possibly still bypassing the bounds if big speedup is
> achieved. This is however a lot more rare than before.
>
> Bootstrapped/regtested x86_64-linux, comitted.
>
> Honza
>
> * ipa-fnsummary.c (ipa_dump_hints): Do not dump array_index.
> (ipa_fn_summary::~ipa_fn_summary): Do not destroy array_index.
> (ipa_fn_summary_t::duplicate): Do not duplicate array_index.
> (array_index_predicate): Remove.
> (analyze_function_body): Account cost for variable ofsetted array
> indexing.
> (estimate_node_size_and_time): Do not compute array index hint.
> (ipa_merge_fn_summary_after_inlining): Do not merge array index
> hint.
> (inline_read_section): Do not read array index hint.
> (ipa_fn_summary_write): Do not write array index hint.
> * doc/invoke.texi (ipa-cp-array-index-hint-bonus): Remove.
> * ipa-cp.c (hint_time_bonus): Remove.
> * ipa-fnsummary.h (ipa_hints_vals): Remove array_index.
> (ipa_fnsummary): Remove array_index.
> * ipa-inline.c (want_inline_small_function_p): Do not use
> array_index.
> (edge_badness): Likewise.
> * params.def (PARAM_IPA_CP_ARRAY_INDEX_HINT_BONUS):
> Remove.
>
> Index: doc/invoke.texi
> ================================================================
> ===
> --- doc/invoke.texi (revision 273450)
> +++ doc/invoke.texi (working copy)
> @@ -11895,12 +11895,6 @@ of iterations of a loop known, it adds a
> @option{ipa-cp-loop-hint-bonus} to the profitability score of the candidate.
>
> -@item ipa-cp-array-index-hint-bonus
> -When IPA-CP determines that a cloning candidate would make the index of -
> an array access known, it adds a bonus of -@option{ipa-cp-array-index-hint-
> bonus} to the profitability -score of the candidate.
> -
> @item ipa-max-aa-steps
> During its analysis of function bodies, IPA-CP employs alias analysis in
> order
> to track values pointed to by function parameters. In order
> Index: ipa-cp.c
> ================================================================
> ===
> --- ipa-cp.c (revision 273450)
> +++ ipa-cp.c (working copy)
> @@ -2607,8 +2607,6 @@ hint_time_bonus (ipa_hints hints)
> int result = 0;
> if (hints & (INLINE_HINT_loop_iterations | INLINE_HINT_loop_stride))
> result += PARAM_VALUE (PARAM_IPA_CP_LOOP_HINT_BONUS);
> - if (hints & INLINE_HINT_array_index)
> - result += PARAM_VALUE (PARAM_IPA_CP_ARRAY_INDEX_HINT_BONUS);
> return result;
> }
>
> Index: ipa-fnsummary.c
> ================================================================
> ===
> --- ipa-fnsummary.c (revision 273450)
> +++ ipa-fnsummary.c (working copy)
> @@ -134,11 +134,6 @@ ipa_dump_hints (FILE *f, ipa_hints hints
> hints &= ~INLINE_HINT_declared_inline;
> fprintf (f, " declared_inline");
> }
> - if (hints & INLINE_HINT_array_index)
> - {
> - hints &= ~INLINE_HINT_array_index;
> - fprintf (f, " array_index");
> - }
> if (hints & INLINE_HINT_known_hot)
> {
> hints &= ~INLINE_HINT_known_hot;
> @@ -549,8 +544,6 @@ ipa_fn_summary::~ipa_fn_summary ()
> edge_predicate_pool.remove (loop_iterations);
> if (loop_stride)
> edge_predicate_pool.remove (loop_stride);
> - if (array_index)
> - edge_predicate_pool.remove (array_index);
> vec_free (conds);
> vec_free (size_time_table);
> }
> @@ -703,8 +696,6 @@ ipa_fn_summary_t::duplicate (cgraph_node
> possible_truths);
> remap_hint_predicate_after_duplication (&info->loop_stride,
> possible_truths);
> - remap_hint_predicate_after_duplication (&info->array_index,
> - possible_truths);
>
> /* If inliner or someone after inliner will ever start producing
> non-trivial clones, we will get trouble with lack of information @@
> -
> 727,12 +718,6 @@ ipa_fn_summary_t::duplicate (cgraph_node
> info->loop_stride = NULL;
> set_hint_predicate (&info->loop_stride, p);
> }
> - if (info->array_index)
> - {
> - predicate p = *info->array_index;
> - info->array_index = NULL;
> - set_hint_predicate (&info->array_index, p);
> - }
> }
> if (!dst->global.inlined_to)
> ipa_update_overall_fn_summary (dst); @@ -894,11 +879,6 @@
> ipa_dump_fn_summary (FILE *f, struct cgr
> fprintf (f, " loop stride:");
> s->loop_stride->dump (f, s->conds);
> }
> - if (s->array_index)
> - {
> - fprintf (f, " array index:");
> - s->array_index->dump (f, s->conds);
> - }
> fprintf (f, " calls:\n");
> dump_ipa_call_summary (f, 4, node, s);
> fprintf (f, "\n");
> @@ -1824,27 +1804,6 @@ predicate_for_phi_result (class ipa_fn_s
> nonconstant_names[SSA_NAME_VERSION (gimple_phi_result (phi))] = *p; }
>
> -/* Return predicate specifying when array index in access OP becomes non-
> constant. */
> -
> -static predicate
> -array_index_predicate (ipa_fn_summary *info,
> - vec< predicate> nonconstant_names, tree op)
> -{
> - predicate p = false;
> - while (handled_component_p (op))
> - {
> - if (TREE_CODE (op) == ARRAY_REF || TREE_CODE (op) ==
> ARRAY_RANGE_REF)
> - {
> - if (TREE_CODE (TREE_OPERAND (op, 1)) == SSA_NAME)
> - p = p.or_with (info->conds,
> - nonconstant_names[SSA_NAME_VERSION
> - (TREE_OPERAND (op, 1))]);
> - }
> - op = TREE_OPERAND (op, 0);
> - }
> - return p;
> -}
> -
> /* For a typical usage of __builtin_expect (a<b, 1), we
> may introduce an extra relation stmt:
> With the builtin, we have
> @@ -2001,7 +1960,6 @@ analyze_function_body (struct cgraph_nod
> vec<predicate> nonconstant_names = vNULL;
> int nblocks, n;
> int *order;
> - predicate array_index = true;
> gimple *fix_builtin_expect_stmt;
>
> gcc_assert (my_function && my_function->cfg); @@ -2146,26 +2104,6 @@
> analyze_function_body (struct cgraph_nod
> this_time);
> }
>
> - if (gimple_assign_load_p (stmt) && nonconstant_names.exists ())
> - {
> - predicate this_array_index;
> - this_array_index =
> - array_index_predicate (info, nonconstant_names,
> - gimple_assign_rhs1 (stmt));
> - if (this_array_index != false)
> - array_index &= this_array_index;
> - }
> - if (gimple_store_p (stmt) && nonconstant_names.exists ())
> - {
> - predicate this_array_index;
> - this_array_index =
> - array_index_predicate (info, nonconstant_names,
> - gimple_get_lhs (stmt));
> - if (this_array_index != false)
> - array_index &= this_array_index;
> - }
> -
> -
> if (is_gimple_call (stmt)
> && !gimple_call_internal_p (stmt))
> {
> @@ -2273,14 +2211,40 @@ analyze_function_body (struct cgraph_nod
> if (dump_file)
> fprintf (dump_file, " fp_expression set\n");
> }
> + }
>
> - gcc_assert (time >= 0);
> - gcc_assert (size >= 0);
> + /* Account cost of address calculations in the statements. */
> + for (unsigned int i = 0; i < gimple_num_ops (stmt); i++)
> + {
> + for (tree op = gimple_op (stmt, i);
> + op && handled_component_p (op);
> + op = TREE_OPERAND (op, 0))
> + if ((TREE_CODE (op) == ARRAY_REF
> + || TREE_CODE (op) == ARRAY_RANGE_REF)
> + && TREE_CODE (TREE_OPERAND (op, 1)) == SSA_NAME)
> + {
> + predicate p = bb_predicate;
> + if (fbi.info)
> + p = p & will_be_nonconstant_expr_predicate
> + (&fbi, info, TREE_OPERAND (op, 1),
> + nonconstant_names);
> + if (p != false)
> + {
> + time += freq;
> + size += 1;
> + if (dump_file)
> + fprintf (dump_file,
> + "\t\tAccounting address calculation.\n");
> + info->account_size_time
> (ipa_fn_summary::size_scale,
> + freq,
> + bb_predicate,
> + p);
> + }
> + }
> }
> +
> }
> }
> - set_hint_predicate (&ipa_fn_summaries->get_create (node)->array_index,
> - array_index);
> free (order);
>
> if (nonconstant_names.exists () && !early) @@ -2783,9 +2747,6 @@
> estimate_node_size_and_time (struct cgra
> if (info->loop_stride
> && !info->loop_stride->evaluate (possible_truths))
> hints |= INLINE_HINT_loop_stride;
> - if (info->array_index
> - && !info->array_index->evaluate (possible_truths))
> - hints |= INLINE_HINT_array_index;
> if (info->scc_no)
> hints |= INLINE_HINT_in_scc;
> if (DECL_DECLARED_INLINE_P (node->decl)) @@ -3106,9 +3067,6 @@
> ipa_merge_fn_summary_after_inlining (str
> remap_hint_predicate (info, callee_info,
> &callee_info->loop_stride,
> operand_map, offset_map, clause,
> &toplev_predicate);
> - remap_hint_predicate (info, callee_info,
> - &callee_info->array_index,
> - operand_map, offset_map, clause,
> &toplev_predicate);
>
> ipa_call_summary *s = ipa_call_summaries->get (edge);
> inline_update_callee_summaries (edge->callee, s->loop_depth); @@ -
> 3366,9 +3324,6 @@ inline_read_section (struct lto_file_dec
> p.stream_in (&ib);
> if (info)
> set_hint_predicate (&info->loop_stride, p);
> - p.stream_in (&ib);
> - if (info)
> - set_hint_predicate (&info->array_index, p);
> for (e = node->callees; e; e = e->next_callee)
> read_ipa_call_summary (&ib, e, info != NULL);
> for (e = node->indirect_calls; e; e = e->next_callee) @@ -3517,10
> +3472,6
> @@ ipa_fn_summary_write (void)
> info->loop_stride->stream_out (ob);
> else
> streamer_write_uhwi (ob, 0);
> - if (info->array_index)
> - info->array_index->stream_out (ob);
> - else
> - streamer_write_uhwi (ob, 0);
> for (edge = cnode->callees; edge; edge = edge->next_callee)
> write_ipa_call_summary (ob, edge);
> for (edge = cnode->indirect_calls; edge; edge = edge->next_callee)
> Index: ipa-fnsummary.h
> ================================================================
> ===
> --- ipa-fnsummary.h (revision 273450)
> +++ ipa-fnsummary.h (working copy)
> @@ -48,11 +48,8 @@ enum ipa_hints_vals {
> if functions are in different modules, inlining may not be so important.
> Set by simple_edge_hints in ipa-inline-analysis.c. */
> INLINE_HINT_cross_module = 64,
> - /* If array indexes of loads/stores become known there may be room for
> - further optimization. */
> - INLINE_HINT_array_index = 128,
> /* We know that the callee is hot by profile. */
> - INLINE_HINT_known_hot = 256
> + INLINE_HINT_known_hot = 128
> };
>
> typedef int ipa_hints;
> @@ -97,7 +94,7 @@ public:
> fp_expressions (false), estimated_stack_size (false),
> stack_frame_offset (false), time (0), size (0), conds (NULL),
> size_time_table (NULL), loop_iterations (NULL), loop_stride (NULL),
> - array_index (NULL), growth (0), scc_no (0)
> + growth (0), scc_no (0)
> {
> }
>
> @@ -111,7 +108,7 @@ public:
> stack_frame_offset (s.stack_frame_offset), time (s.time), size (s.size),
> conds (s.conds), size_time_table (s.size_time_table),
> loop_iterations (s.loop_iterations), loop_stride (s.loop_stride),
> - array_index (s.array_index), growth (s.growth), scc_no (s.scc_no)
> + growth (s.growth), scc_no (s.scc_no)
> {}
>
> /* Default constructor. */
> @@ -157,8 +154,6 @@ public:
> /* Predicate on when some loop in the function becomes to have known
> stride. */
> predicate * GTY((skip)) loop_stride;
> - /* Predicate on when some array indexes become constants. */
> - predicate * GTY((skip)) array_index;
> /* Estimated growth for inlining all copies of the function before start
> of small functions inlining.
> This value will get out of date as the callers are duplicated, but
> Index: ipa-inline.c
> ================================================================
> ===
> --- ipa-inline.c (revision 273450)
> +++ ipa-inline.c (working copy)
> @@ -807,7 +807,6 @@ want_inline_small_function_p (struct cgr
> || (!(hints & (INLINE_HINT_indirect_call
> | INLINE_HINT_known_hot
> | INLINE_HINT_loop_iterations
> - | INLINE_HINT_array_index
> | INLINE_HINT_loop_stride))
> && !(big_speedup = big_speedup_p (e)))))
> {
> @@ -833,7 +832,6 @@ want_inline_small_function_p (struct cgr
> && !(hints & INLINE_HINT_known_hot)
> && growth >= ((hints & (INLINE_HINT_indirect_call
> | INLINE_HINT_loop_iterations
> - | INLINE_HINT_array_index
> | INLINE_HINT_loop_stride))
> ? MAX (MAX_INLINE_INSNS_AUTO,
> MAX_INLINE_INSNS_SINGLE)
> @@ -1227,7 +1225,6 @@ edge_badness (struct cgraph_edge *edge,
> badness = badness.shift (badness > 0 ? 4 : -4);
> if ((hints & (INLINE_HINT_indirect_call
> | INLINE_HINT_loop_iterations
> - | INLINE_HINT_array_index
> | INLINE_HINT_loop_stride))
> || callee_info->growth <= 0)
> badness = badness.shift (badness > 0 ? -2 : 2);
> Index: params.def
> ================================================================
> ===
> --- params.def (revision 273450)
> +++ params.def (working copy)
> @@ -1109,12 +1109,6 @@ DEFPARAM (PARAM_IPA_CP_LOOP_HINT_BONUS,
> "bounds or strides known.",
> 64, 0, 0)
>
> -DEFPARAM (PARAM_IPA_CP_ARRAY_INDEX_HINT_BONUS,
> - "ipa-cp-array-index-hint-bonus",
> - "Compile-time bonus IPA-CP assigns to candidates which make an
> array "
> - "index known.",
> - 48, 0, 0)
> -
> DEFPARAM (PARAM_IPA_MAX_AA_STEPS,
> "ipa-max-aa-steps",
> "Maximum number of statements that will be visited by IPA formal "
