--- /dev/null
+// Dependency fusion reordering pass.
+// Copyright (C) 2025 Free Software Foundation, Inc.
+//
+// This file is part of GCC.
+//
+// GCC is free software; you can redistribute it and/or modify it under
+// the terms of the GNU General Public License as published by the Free
+// Software Foundation; either version 3, or (at your option) any later
+// version.
+//
+// GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or
+// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+// for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with GCC; see the file COPYING3. If not see
+// <http://www.gnu.org/licenses/>.
+//
+// This pass uses the RTL-SSA representation to detect def-use pairs that are
+// macro-op-fusible in the current microarchitecture (using the
+// macro_fusion_pair_p () target hook) and place them next to one another, if
+// possible.
+
+#define INCLUDE_ALGORITHM
+#define INCLUDE_FUNCTIONAL
+#define INCLUDE_MEMORY
+#define INCLUDE_ARRAY
+#include "config.h"
+#include "system.h"
+#include "coretypes.h"
+#include "backend.h"
+#include "rtl.h"
+#include "df.h"
+#include "rtl-ssa.h"
+#include "print-rtl.h"
+#include "tree-pass.h"
+#include "cfgcleanup.h"
+#include "target.h"
+#include "dbgcnt.h"
+
+namespace {
+const pass_data pass_data_dep_fusion =
+{
+ RTL_PASS, // type
+ "dep_fusion", // name
+ OPTGROUP_NONE, // optinfo_flags
+ TV_NONE, // tv_id
+ 0, // properties_required
+ 0, // properties_provided
+ 0, // properties_destroyed
+ 0, // todo_flags_start
+ TODO_df_finish, // todo_flags_finish
+};
+
+class pass_dep_fusion : public rtl_opt_pass
+{
+public:
+ pass_dep_fusion (gcc::context *ctxt)
+ : rtl_opt_pass (pass_data_dep_fusion, ctxt)
+ {}
+
+ // opt_pass methods:
+ opt_pass *clone () override { return new pass_dep_fusion (m_ctxt); }
+ bool gate (function *) override;
+ unsigned int execute (function *) override;
+};
+
+bool
+pass_dep_fusion::gate (function *)
+{
+ return optimize > 0 && flag_dep_fusion;
+}
+
+unsigned int
+pass_dep_fusion::execute (function *fn)
+{
+ // Initialization.
+ calculate_dominance_info (CDI_DOMINATORS);
+ df_analyze ();
+ crtl->ssa = new rtl_ssa::function_info (fn);
+
+ init_recog_no_volatile ();
+
+ for (rtl_ssa::insn_info *insn = *crtl->ssa->nondebug_insns ().begin ();
+ insn;
+ insn = insn->next_nondebug_insn ())
+ {
+ if (!insn->can_be_optimized () || insn->num_defs () != 1)
+ continue;
+
+ rtl_ssa::set_info *def = single_set_info (insn);
+ if (!def)
+ continue;
+
+ rtl_ssa::use_info *use_insn = def->single_nondebug_insn_use ();
+ if (!use_insn
+ || !use_insn->insn ()->can_be_optimized ()
+ || !targetm.sched.macro_fusion_pair_p (insn->rtl (),
+ use_insn->insn ()->rtl ()))
+ continue;
+
+ auto attempt = crtl->ssa->new_change_attempt ();
+ rtl_ssa::insn_change change (use_insn->insn ());
+
+ if (use_insn->insn () != insn->next_any_insn ())
+ {
+ if (!can_move_insn_p (use_insn->insn ()))
+ continue;
+
+ change.move_range = insn;
+ if (!rtl_ssa::restrict_movement (change))
+ continue;
+
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, "Moved a single-use instruction:\n");
+ dump_insn_slim (dump_file, use_insn->insn ()->rtl ());
+ fprintf (dump_file, "right after its definition:\n");
+ dump_insn_slim (dump_file, insn->rtl ());
+ }
+ }
+
+ SCHED_GROUP_P (use_insn->insn ()->rtl ()) = 1;
+ confirm_change_group ();
+ crtl->ssa->change_insn (change);
+ }
+
+ // Finalization.
+ if (crtl->ssa->perform_pending_updates ())
+ cleanup_cfg (0);
+
+ delete crtl->ssa;
+
+ init_recog ();
+ free_dominance_info (CDI_DOMINATORS);
+ return 0;
+}
+
+} // end namespace
+
+// Create a new dep fusion pass instance.
+
+rtl_opt_pass *
+make_pass_dep_fusion (gcc::context *ctxt)
+{
+ return new pass_dep_fusion (ctxt);
+}
-fcse-follow-jumps -fcse-skip-blocks -fcx-fortran-rules
-fcx-limited-range -fcx-method
-fdata-sections -fdce -fdelayed-branch
--fdelete-null-pointer-checks -fdevirtualize -fdevirtualize-speculatively
--fdevirtualize-at-ltrans -fdse
+-fdelete-null-pointer-checks -fdep-fusion -fdevirtualize
+-fdevirtualize-speculatively -fdevirtualize-at-ltrans -fdse
-fearly-inlining -fipa-sra -fexpensive-optimizations -ffat-lto-objects
-ffast-math -ffinite-math-only -ffloat-store -fexcess-precision=@var{style}
-ffinite-loops
-fcode-hoisting
-fcrossjumping
-fcse-follow-jumps -fcse-skip-blocks
--fdelete-null-pointer-checks
+-fdelete-null-pointer-checks -fdep-fusion
-fdevirtualize -fdevirtualize-speculatively
-fexpensive-optimizations
-ffinite-loops
Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}.
+@opindex fdep-fusion
+@item -fdep-fusion
+Detect macro-op fusible pairs consisting of single-use instructions and their
+uses, and place such pairs together in the instruction stream to increase
+fusion opportunities in hardware. This pass is executed once before register
+allocation, and another time before register renaming.
+
+Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}.
+
@opindex ftracer
@item -ftracer
Perform tail duplication to enlarge superblock size. This transformation
{ OPT_LEVELS_2_PLUS, OPT_fcode_hoisting, NULL, 1 },
{ OPT_LEVELS_2_PLUS, OPT_fcrossjumping, NULL, 1 },
{ OPT_LEVELS_2_PLUS, OPT_fcse_follow_jumps, NULL, 1 },
+ { OPT_LEVELS_2_PLUS, OPT_fdep_fusion, NULL, 1 },
{ OPT_LEVELS_2_PLUS, OPT_fdevirtualize, NULL, 1 },
{ OPT_LEVELS_2_PLUS, OPT_fdevirtualize_speculatively, NULL, 1 },
{ OPT_LEVELS_2_PLUS, OPT_fexpensive_optimizations, NULL, 1 },
projects / thirdparty / gcc.git / commitdiff
