From: Jakub Jelinek Date: Fri, 8 Nov 2019 10:53:50 +0000 (+0100) Subject: re PR target/92038 (Extremely inefficient x86_64 code for trivally copyable types... X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=5384a8027098be99e8d22613583a4f235d515a78;p=gcc.git re PR target/92038 (Extremely inefficient x86_64 code for trivally copyable types passed in registers.) PR target/92038 * gimple-ssa-store-merging.c (find_constituent_stores): For return value only, return non-NULL if there is a single non-clobber constituent store even if there are constituent clobbers and return one of clobber constituent stores if all constituent stores are clobbers. (split_group): Handle clobbers. (imm_store_chain_info::output_merged_store): When computing bzero_first, look after all clobbers at the start. Don't count clobber stmts in orig_num_stmts, except if the first orig store is a clobber covering the whole area and split_stores cover the whole area, consider equal number of stmts ok. Punt if split_stores contains only ->orig stores and their number plus number of original clobbers is equal to original number of stmts. For ->orig, look past clobbers in the constituent stores. (imm_store_chain_info::output_merged_stores): Don't remove clobber stmts. (rhs_valid_for_store_merging_p): Don't return false for clobber stmt rhs. (store_valid_for_store_merging_p): Allow clobber stmts. (verify_clear_bit_region_be): Fix up a thinko in function comment. * g++.dg/opt/store-merging-1.C: New test. * g++.dg/opt/store-merging-2.C: New test. * g++.dg/opt/store-merging-3.C: New test. From-SVN: r277963 --- diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 3649706d319..277c21c9e83 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,5 +1,27 @@ 2019-11-08 Jakub Jelinek + PR target/92038 + * gimple-ssa-store-merging.c (find_constituent_stores): For return + value only, return non-NULL if there is a single non-clobber + constituent store even if there are constituent clobbers and return + one of clobber constituent stores if all constituent stores are + clobbers. + (split_group): Handle clobbers. + (imm_store_chain_info::output_merged_store): When computing + bzero_first, look after all clobbers at the start. Don't count + clobber stmts in orig_num_stmts, except if the first orig store is + a clobber covering the whole area and split_stores cover the whole + area, consider equal number of stmts ok. Punt if split_stores + contains only ->orig stores and their number plus number of original + clobbers is equal to original number of stmts. For ->orig, look past + clobbers in the constituent stores. + (imm_store_chain_info::output_merged_stores): Don't remove clobber + stmts. + (rhs_valid_for_store_merging_p): Don't return false for clobber stmt + rhs. + (store_valid_for_store_merging_p): Allow clobber stmts. + (verify_clear_bit_region_be): Fix up a thinko in function comment. + PR c++/92384 * function.c (assign_parm_setup_block, assign_parm_setup_stack): Don't copy TYPE_EMPTY_P arguments from data->entry_parm to data->stack_parm diff --git a/gcc/gimple-ssa-store-merging.c b/gcc/gimple-ssa-store-merging.c index 270159b518d..c6dbac268c8 100644 --- a/gcc/gimple-ssa-store-merging.c +++ b/gcc/gimple-ssa-store-merging.c @@ -3110,7 +3110,8 @@ split_store::split_store (unsigned HOST_WIDE_INT bp, /* Record all stores in GROUP that write to the region starting at BITPOS and is of size BITSIZE. Record infos for such statements in STORES if non-NULL. The stores in GROUP must be sorted by bitposition. Return INFO - if there is exactly one original store in the range. */ + if there is exactly one original store in the range (in that case ignore + clobber stmts, unless there are only clobber stmts). */ static store_immediate_info * find_constituent_stores (class merged_store_group *group, @@ -3146,16 +3147,24 @@ find_constituent_stores (class merged_store_group *group, if (stmt_start >= end) return ret; + if (gimple_clobber_p (info->stmt)) + { + if (stores) + stores->safe_push (info); + if (ret == NULL) + ret = info; + continue; + } if (stores) { stores->safe_push (info); - if (ret) + if (ret && !gimple_clobber_p (ret->stmt)) { ret = NULL; second = true; } } - else if (ret) + else if (ret && !gimple_clobber_p (ret->stmt)) return NULL; if (!second) ret = info; @@ -3347,13 +3356,17 @@ split_group (merged_store_group *group, bool allow_unaligned_store, if (bzero_first) { - first = 1; + store_immediate_info *gstore; + FOR_EACH_VEC_ELT (group->stores, first, gstore) + if (!gimple_clobber_p (gstore->stmt)) + break; + ++first; ret = 1; if (split_stores) { split_store *store - = new split_store (bytepos, group->stores[0]->bitsize, align_base); - store->orig_stores.safe_push (group->stores[0]); + = new split_store (bytepos, gstore->bitsize, align_base); + store->orig_stores.safe_push (gstore); store->orig = true; any_orig = true; split_stores->safe_push (store); @@ -3377,6 +3390,7 @@ split_group (merged_store_group *group, bool allow_unaligned_store, unsigned HOST_WIDE_INT align_bitpos = (try_bitpos - align_base) & (group_align - 1); unsigned HOST_WIDE_INT align = group_align; + bool found_orig = false; if (align_bitpos) align = least_bit_hwi (align_bitpos); if (!allow_unaligned_store) @@ -3408,7 +3422,7 @@ split_group (merged_store_group *group, bool allow_unaligned_store, } store_immediate_info *info = find_constituent_stores (group, NULL, &first, try_bitpos, try_size); - if (info) + if (info && !gimple_clobber_p (info->stmt)) { /* If there is just one original statement for the range, see if we can just reuse the original store which could be even larger @@ -3419,8 +3433,30 @@ split_group (merged_store_group *group, bool allow_unaligned_store, stmt_end - try_bitpos); if (info && info->bitpos >= try_bitpos) { - try_size = stmt_end - try_bitpos; - goto found; + store_immediate_info *info2 = NULL; + unsigned int first_copy = first; + if (info->bitpos > try_bitpos + && stmt_end - try_bitpos <= try_size) + { + info2 = find_constituent_stores (group, NULL, &first_copy, + try_bitpos, + info->bitpos - try_bitpos); + gcc_assert (info2 == NULL || gimple_clobber_p (info2->stmt)); + } + if (info2 == NULL && stmt_end - try_bitpos < try_size) + { + info2 = find_constituent_stores (group, NULL, &first_copy, + stmt_end, + (try_bitpos + try_size) + - stmt_end); + gcc_assert (info2 == NULL || gimple_clobber_p (info2->stmt)); + } + if (info2 == NULL) + { + try_size = stmt_end - try_bitpos; + found_orig = true; + goto found; + } } } @@ -3435,7 +3471,7 @@ split_group (merged_store_group *group, bool allow_unaligned_store, && (!bzero_first || group->val[try_pos - bytepos + nonmasked - 1] != 0)) break; - if (nonmasked == 0) + if (nonmasked == 0 || (info && gimple_clobber_p (info->stmt))) { /* If entire try_size range is padding, skip it. */ try_pos += try_size / BITS_PER_UNIT; @@ -3483,8 +3519,14 @@ split_group (merged_store_group *group, bool allow_unaligned_store, info = find_constituent_stores (group, &store->orig_stores, &first, try_bitpos, try_size); if (info + && !gimple_clobber_p (info->stmt) && info->bitpos >= try_bitpos - && info->bitpos + info->bitsize <= try_bitpos + try_size) + && info->bitpos + info->bitsize <= try_bitpos + try_size + && (store->orig_stores.length () == 1 + || found_orig + || (info->bitpos == try_bitpos + && (info->bitpos + info->bitsize + == try_bitpos + try_size)))) { store->orig = true; any_orig = true; @@ -3671,14 +3713,32 @@ imm_store_chain_info::output_merged_store (merged_store_group *group) = !STRICT_ALIGNMENT && PARAM_VALUE (PARAM_STORE_MERGING_ALLOW_UNALIGNED); bool allow_unaligned_load = allow_unaligned_store; bool bzero_first = false; - if (group->stores[0]->rhs_code == INTEGER_CST - && TREE_CODE (gimple_assign_rhs1 (group->stores[0]->stmt)) == CONSTRUCTOR - && CONSTRUCTOR_NELTS (gimple_assign_rhs1 (group->stores[0]->stmt)) == 0 - && group->start == group->stores[0]->bitpos - && group->width == group->stores[0]->bitsize - && (group->start % BITS_PER_UNIT) == 0 - && (group->width % BITS_PER_UNIT) == 0) - bzero_first = true; + store_immediate_info *store; + unsigned int num_clobber_stmts = 0; + if (group->stores[0]->rhs_code == INTEGER_CST) + { + FOR_EACH_VEC_ELT (group->stores, i, store) + if (gimple_clobber_p (store->stmt)) + num_clobber_stmts++; + else if (TREE_CODE (gimple_assign_rhs1 (store->stmt)) == CONSTRUCTOR + && CONSTRUCTOR_NELTS (gimple_assign_rhs1 (store->stmt)) == 0 + && group->start == store->bitpos + && group->width == store->bitsize + && (group->start % BITS_PER_UNIT) == 0 + && (group->width % BITS_PER_UNIT) == 0) + { + bzero_first = true; + break; + } + else + break; + FOR_EACH_VEC_ELT_FROM (group->stores, i, store, i) + if (gimple_clobber_p (store->stmt)) + num_clobber_stmts++; + if (num_clobber_stmts == orig_num_stmts) + return false; + orig_num_stmts -= num_clobber_stmts; + } if (allow_unaligned_store || bzero_first) { /* If unaligned stores are allowed, see how many stores we'd emit @@ -3710,8 +3770,35 @@ imm_store_chain_info::output_merged_store (merged_store_group *group) split_group (group, allow_unaligned_store, allow_unaligned_load, bzero_first, &split_stores, &total_orig, &total_new); - if (split_stores.length () >= orig_num_stmts) + /* Determine if there is a clobber covering the whole group at the start, + followed by proposed split stores that cover the whole group. In that + case, prefer the transformation even if + split_stores.length () == orig_num_stmts. */ + bool clobber_first = false; + if (num_clobber_stmts + && gimple_clobber_p (group->stores[0]->stmt) + && group->start == group->stores[0]->bitpos + && group->width == group->stores[0]->bitsize + && (group->start % BITS_PER_UNIT) == 0 + && (group->width % BITS_PER_UNIT) == 0) + { + clobber_first = true; + unsigned HOST_WIDE_INT pos = group->start / BITS_PER_UNIT; + FOR_EACH_VEC_ELT (split_stores, i, split_store) + if (split_store->bytepos != pos) + { + clobber_first = false; + break; + } + else + pos += split_store->size / BITS_PER_UNIT; + if (pos != (group->start + group->width) / BITS_PER_UNIT) + clobber_first = false; + } + + if (split_stores.length () >= orig_num_stmts + clobber_first) { + /* We didn't manage to reduce the number of statements. Bail out. */ if (dump_file && (dump_flags & TDF_DETAILS)) fprintf (dump_file, "Exceeded original number of stmts (%u)." @@ -3734,6 +3821,36 @@ imm_store_chain_info::output_merged_store (merged_store_group *group) delete split_store; return false; } + if (group->stores[0]->rhs_code == INTEGER_CST) + { + bool all_orig = true; + FOR_EACH_VEC_ELT (split_stores, i, split_store) + if (!split_store->orig) + { + all_orig = false; + break; + } + if (all_orig) + { + unsigned int cnt = split_stores.length (); + store_immediate_info *store; + FOR_EACH_VEC_ELT (group->stores, i, store) + if (gimple_clobber_p (store->stmt)) + ++cnt; + /* Punt if we wouldn't make any real changes, i.e. keep all + orig stmts + all clobbers. */ + if (cnt == group->stores.length ()) + { + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, "Exceeded original number of stmts (%u)." + " Not profitable to emit new sequence.\n", + orig_num_stmts); + FOR_EACH_VEC_ELT (split_stores, i, split_store) + delete split_store; + return false; + } + } + } gimple_stmt_iterator last_gsi = gsi_for_stmt (group->last_stmt); gimple_seq seq = NULL; @@ -3742,6 +3859,13 @@ imm_store_chain_info::output_merged_store (merged_store_group *group) new_vuse = gimple_vuse (group->last_stmt); tree bswap_res = NULL_TREE; + /* Clobbers are not removed. */ + if (gimple_clobber_p (group->last_stmt)) + { + new_vuse = make_ssa_name (gimple_vop (cfun), group->last_stmt); + gimple_set_vdef (group->last_stmt, new_vuse); + } + if (group->stores[0]->rhs_code == LROTATE_EXPR || group->stores[0]->rhs_code == NOP_EXPR) { @@ -3865,9 +3989,17 @@ imm_store_chain_info::output_merged_store (merged_store_group *group) location_t loc; if (split_store->orig) { - /* If there is just a single constituent store which covers - the whole area, just reuse the lhs and rhs. */ - gimple *orig_stmt = split_store->orig_stores[0]->stmt; + /* If there is just a single non-clobber constituent store + which covers the whole area, just reuse the lhs and rhs. */ + gimple *orig_stmt = NULL; + store_immediate_info *store; + unsigned int j; + FOR_EACH_VEC_ELT (split_store->orig_stores, j, store) + if (!gimple_clobber_p (store->stmt)) + { + orig_stmt = store->stmt; + break; + } dest = gimple_assign_lhs (orig_stmt); src = gimple_assign_rhs1 (orig_stmt); loc = gimple_location (orig_stmt); @@ -4194,6 +4326,9 @@ imm_store_chain_info::output_merged_store (merged_store_group *group) print_gimple_seq (dump_file, seq, 0, TDF_VOPS | TDF_MEMSYMS); } + if (gimple_clobber_p (group->last_stmt)) + update_stmt (group->last_stmt); + if (group->lp_nr > 0) { /* We're going to insert a sequence of (potentially) throwing stores @@ -4279,6 +4414,10 @@ imm_store_chain_info::output_merged_stores () { gimple *stmt = store->stmt; gimple_stmt_iterator gsi = gsi_for_stmt (stmt); + /* Don't remove clobbers, they are still useful even if + everything is overwritten afterwards. */ + if (gimple_clobber_p (stmt)) + continue; gsi_remove (&gsi, true); if (store->lp_nr) remove_stmt_from_eh_lp (stmt); @@ -4361,7 +4500,6 @@ rhs_valid_for_store_merging_p (tree rhs) { unsigned HOST_WIDE_INT size; if (TREE_CODE (rhs) == CONSTRUCTOR - && !TREE_CLOBBER_P (rhs) && CONSTRUCTOR_NELTS (rhs) == 0 && TYPE_SIZE_UNIT (TREE_TYPE (rhs)) && tree_fits_uhwi_p (TYPE_SIZE_UNIT (TREE_TYPE (rhs)))) @@ -4794,7 +4932,7 @@ store_valid_for_store_merging_p (gimple *stmt) return gimple_assign_single_p (stmt) && gimple_vdef (stmt) && lhs_valid_for_store_merging_p (gimple_assign_lhs (stmt)) - && !gimple_has_volatile_ops (stmt); + && (!gimple_has_volatile_ops (stmt) || gimple_clobber_p (stmt)); } enum basic_block_status { BB_INVALID, BB_VALID, BB_EXTENDED_VALID }; @@ -4875,7 +5013,7 @@ pass_store_merging::execute (function *fun) if (is_gimple_debug (stmt)) continue; - if (gimple_has_volatile_ops (stmt)) + if (gimple_has_volatile_ops (stmt) && !gimple_clobber_p (stmt)) { /* Terminate all chains. */ if (dump_file && (dump_flags & TDF_DETAILS)) @@ -5022,7 +5160,7 @@ verify_clear_bit_region (void) verify_array_eq (in, expected, sizeof in); } -/* Test verify_clear_bit_region_be that it clears exactly the bits asked and +/* Test clear_bit_region_be that it clears exactly the bits asked and nothing more. */ static void diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 6e3027ff046..9ab6b0de4dc 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,5 +1,10 @@ 2019-11-08 Jakub Jelinek + PR target/92038 + * g++.dg/opt/store-merging-1.C: New test. + * g++.dg/opt/store-merging-2.C: New test. + * g++.dg/opt/store-merging-3.C: New test. + PR c++/92384 * g++.dg/torture/pr92384.C: New test. diff --git a/gcc/testsuite/g++.dg/opt/store-merging-1.C b/gcc/testsuite/g++.dg/opt/store-merging-1.C new file mode 100644 index 00000000000..c7f294ec386 --- /dev/null +++ b/gcc/testsuite/g++.dg/opt/store-merging-1.C @@ -0,0 +1,9 @@ +// PR target/92038 +// { dg-do compile { target int32 } } +// { dg-require-effective-target store_merge } +// { dg-options "-O2 -flifetime-dse=2 -fdump-tree-store-merging-details" } +// { dg-final { scan-tree-dump "New sequence of \[12] stores to replace old one of 2 stores" "store-merging" } } + +struct S { S () : a (0), b (0) {} int a; char b; char c[3]; }; +void foo (struct S); +void bar (void) { struct S s; foo (s); } diff --git a/gcc/testsuite/g++.dg/opt/store-merging-2.C b/gcc/testsuite/g++.dg/opt/store-merging-2.C new file mode 100644 index 00000000000..3c17033764b --- /dev/null +++ b/gcc/testsuite/g++.dg/opt/store-merging-2.C @@ -0,0 +1,10 @@ +// PR target/92038 +// { dg-do compile { target int32 } } +// { dg-require-effective-target store_merge } +// { dg-options "-O2 -flifetime-dse=2 -fdump-tree-store-merging-details" } +// { dg-final { scan-tree-dump "New sequence of 2 stores to replace old one of 3 stores" "store-merging" } } + +struct T { char a[128]; }; +struct S { S () : a () { a.a[12] = 0; a.a[13] = 1; a.a[14] = 0; a.a[15] = 6; } T a; }; +void foo (S &); +void bar (void) { S s; foo (s); } diff --git a/gcc/testsuite/g++.dg/opt/store-merging-3.C b/gcc/testsuite/g++.dg/opt/store-merging-3.C new file mode 100644 index 00000000000..e3c72ab7407 --- /dev/null +++ b/gcc/testsuite/g++.dg/opt/store-merging-3.C @@ -0,0 +1,8 @@ +// PR target/92038 +// { dg-do compile } +// { dg-options "-O2 -flifetime-dse=2" } + +struct A { A (int); int a; }; +struct B { B () : b(0) {} A b; }; +struct C { C () : c () {} bool c; B d; }; +void foo () { C d; }