/* Optimize jump instructions, for GNU compiler.
Copyright (C) 1987, 1988, 1989, 1991, 1992, 1993, 1994, 1995, 1996, 1997
- 1998, 1999, 2000, 2001 Free Software Foundation, Inc.
+ 1998, 1999, 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
-This file is part of GNU CC.
+This file is part of GCC.
-GNU CC 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 2, or (at your option)
-any later version.
+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 2, or (at your option) any later
+version.
-GNU CC 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.
+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 GNU CC; see the file COPYING. If not, write to
-the Free Software Foundation, 59 Temple Place - Suite 330,
-Boston, MA 02111-1307, USA. */
+along with GCC; see the file COPYING. If not, write to the Free
+Software Foundation, 59 Temple Place - Suite 330, Boston, MA
+02111-1307, USA. */
-/* This is the jump-optimization pass of the compiler.
- It is run two or three times: once before cse, sometimes once after cse,
- and once after reload (before final).
-
- jump_optimize deletes unreachable code and labels that are not used.
- It also deletes jumps that jump to the following insn,
- and simplifies jumps around unconditional jumps and jumps
- to unconditional jumps.
+/* This is the pathetic reminder of old fame of the jump-optimization pass
+ of the compiler. Now it contains basically set of utility function to
+ operate with jumps.
Each CODE_LABEL has a count of the times it is used
stored in the LABEL_NUSES internal field, and each JUMP_INSN
formerly used them. The JUMP_LABEL info is sometimes looked
at by later passes.
- Optionally, cross-jumping can be done. Currently it is done
- only the last time (when after reload and before final).
- In fact, the code for cross-jumping now assumes that register
- allocation has been done, since it uses `rtx_renumbered_equal_p'.
-
- Jump optimization is done after cse when cse's constant-propagation
- causes jumps to become unconditional or to be deleted.
-
- Unreachable loops are not detected here, because the labels
- have references and the insns appear reachable from the labels.
- find_basic_blocks in flow.c finds and deletes such loops.
-
- The subroutines delete_insn, redirect_jump, and invert_jump are used
+ The subroutines redirect_jump and invert_jump are used
from other passes as well. */
#include "config.h"
#include "system.h"
+#include "coretypes.h"
+#include "tm.h"
#include "rtl.h"
#include "tm_p.h"
#include "flags.h"
#include "expr.h"
#include "real.h"
#include "except.h"
+#include "diagnostic.h"
#include "toplev.h"
#include "reload.h"
#include "predict.h"
+#include "timevar.h"
-/* ??? Eventually must record somehow the labels used by jumps
- from nested functions. */
-/* Pre-record the next or previous real insn for each label?
- No, this pass is very fast anyway. */
-/* Condense consecutive labels?
- This would make life analysis faster, maybe. */
/* Optimize jump y; x: ... y: jumpif... x?
Don't know if it is worth bothering with. */
/* Optimize two cases of conditional jump to conditional jump?
or even change what is live at any point.
So perhaps let combiner do it. */
-/* Vector indexed by uid.
- For each CODE_LABEL, index by its uid to get first unconditional jump
- that jumps to the label.
- For each JUMP_INSN, index by its uid to get the next unconditional jump
- that jumps to the same label.
- Element 0 is the start of a chain of all return insns.
- (It is safe to use element 0 because insn uid 0 is not used. */
-
-static rtx *jump_chain;
-
-/* Maximum index in jump_chain. */
-
-static int max_jump_chain;
-
-/* Indicates whether death notes are significant in cross jump analysis.
- Normally they are not significant, because of A and B jump to C,
- and R dies in A, it must die in B. But this might not be true after
- stack register conversion, and we must compare death notes in that
- case. */
-
-static int cross_jump_death_matters = 0;
-
-static int init_label_info PARAMS ((rtx));
-static void delete_barrier_successors PARAMS ((rtx));
-static void mark_all_labels PARAMS ((rtx, int));
-static rtx delete_unreferenced_labels PARAMS ((rtx));
-static void delete_noop_moves PARAMS ((rtx));
-static int duplicate_loop_exit_test PARAMS ((rtx));
-static void find_cross_jump PARAMS ((rtx, rtx, int, rtx *, rtx *));
-static void do_cross_jump PARAMS ((rtx, rtx, rtx));
-static int jump_back_p PARAMS ((rtx, rtx));
-static int tension_vector_labels PARAMS ((rtx, int));
-static void delete_computation PARAMS ((rtx));
-static void redirect_exp_1 PARAMS ((rtx *, rtx, rtx, rtx));
-static int redirect_exp PARAMS ((rtx, rtx, rtx));
-static void invert_exp_1 PARAMS ((rtx));
-static int invert_exp PARAMS ((rtx));
-static void delete_from_jump_chain PARAMS ((rtx));
-static int delete_labelref_insn PARAMS ((rtx, rtx, int));
-static void mark_modified_reg PARAMS ((rtx, rtx, void *));
-static void redirect_tablejump PARAMS ((rtx, rtx));
-static void jump_optimize_1 PARAMS ((rtx, int, int, int, int, int));
-static int returnjump_p_1 PARAMS ((rtx *, void *));
-static void delete_prior_computation PARAMS ((rtx, rtx));
+static rtx next_nonnote_insn_in_loop (rtx);
+static void init_label_info (rtx);
+static void mark_all_labels (rtx);
+static int duplicate_loop_exit_test (rtx);
+static void delete_computation (rtx);
+static void redirect_exp_1 (rtx *, rtx, rtx, rtx);
+static int redirect_exp (rtx, rtx, rtx);
+static void invert_exp_1 (rtx);
+static int invert_exp (rtx);
+static int returnjump_p_1 (rtx *, void *);
+static void delete_prior_computation (rtx, rtx);
\f
-/* Main external entry point into the jump optimizer. See comments before
- jump_optimize_1 for descriptions of the arguments. */
-void
-jump_optimize (f, cross_jump, noop_moves, after_regscan)
- rtx f;
- int cross_jump;
- int noop_moves;
- int after_regscan;
-{
- jump_optimize_1 (f, cross_jump, noop_moves, after_regscan, 0, 0);
-}
-
/* Alternate entry into the jump optimizer. This entry point only rebuilds
the JUMP_LABEL field in jumping insns and REG_LABEL notes in non-jumping
instructions. */
void
-rebuild_jump_labels (f)
- rtx f;
+rebuild_jump_labels (rtx f)
{
- jump_optimize_1 (f, 0, 0, 0, 1, 0);
-}
-
-/* Alternate entry into the jump optimizer. Do only trivial optimizations. */
-
-void
-jump_optimize_minimal (f)
- rtx f;
-{
- jump_optimize_1 (f, 0, 0, 0, 0, 1);
-}
-\f
-/* Delete no-op jumps and optimize jumps to jumps
- and jumps around jumps.
- Delete unused labels and unreachable code.
-
- If CROSS_JUMP is 1, detect matching code
- before a jump and its destination and unify them.
- If CROSS_JUMP is 2, do cross-jumping, but pay attention to death notes.
-
- If NOOP_MOVES is nonzero, delete no-op move insns.
-
- If AFTER_REGSCAN is nonzero, then this jump pass is being run immediately
- after regscan, and it is safe to use regno_first_uid and regno_last_uid.
-
- If MARK_LABELS_ONLY is nonzero, then we only rebuild the jump chain
- and JUMP_LABEL field for jumping insns.
-
- If `optimize' is zero, don't change any code,
- just determine whether control drops off the end of the function.
- This case occurs when we have -W and not -O.
- It works because `delete_insn' checks the value of `optimize'
- and refrains from actually deleting when that is 0.
-
- If MINIMAL is nonzero, then we only perform trivial optimizations:
-
- * Removal of unreachable code after BARRIERs.
- * Removal of unreferenced CODE_LABELs.
- * Removal of a jump to the next instruction.
- * Removal of a conditional jump followed by an unconditional jump
- to the same target as the conditional jump.
- * Simplify a conditional jump around an unconditional jump.
- * Simplify a jump to a jump.
- * Delete extraneous line number notes.
- */
-
-static void
-jump_optimize_1 (f, cross_jump, noop_moves, after_regscan,
- mark_labels_only, minimal)
- rtx f;
- int cross_jump;
- int noop_moves;
- int after_regscan;
- int mark_labels_only;
- int minimal;
-{
- register rtx insn, next;
- int changed;
- int old_max_reg;
- int first = 1;
- int max_uid = 0;
- rtx last_insn;
-#ifdef HAVE_trap
- enum rtx_code reversed_code;
-#endif
-
- cross_jump_death_matters = (cross_jump == 2);
- max_uid = init_label_info (f) + 1;
-
- /* Leave some extra room for labels and duplicate exit test insns
- we make. */
- max_jump_chain = max_uid * 14 / 10;
- jump_chain = (rtx *) xcalloc (max_jump_chain, sizeof (rtx));
+ rtx insn;
- mark_all_labels (f, cross_jump);
+ timevar_push (TV_REBUILD_JUMP);
+ init_label_info (f);
+ mark_all_labels (f);
/* Keep track of labels used from static data; we don't track them
closely enough to delete them here, so make sure their reference
for (insn = forced_labels; insn; insn = XEXP (insn, 1))
if (GET_CODE (XEXP (insn, 0)) == CODE_LABEL)
LABEL_NUSES (XEXP (insn, 0))++;
-
- /* Keep track of labels used for marking handlers for exception
- regions; they cannot usually be deleted. */
-
- for (insn = exception_handler_labels; insn; insn = XEXP (insn, 1))
- if (GET_CODE (XEXP (insn, 0)) == CODE_LABEL)
- LABEL_NUSES (XEXP (insn, 0))++;
-
- /* Quit now if we just wanted to rebuild the JUMP_LABEL and REG_LABEL
- notes and recompute LABEL_NUSES. */
- if (mark_labels_only)
- goto end;
-
- delete_barrier_successors (f);
-
- last_insn = delete_unreferenced_labels (f);
-
- if (noop_moves)
- delete_noop_moves (f);
-
- /* Now iterate optimizing jumps until nothing changes over one pass. */
- changed = 1;
- old_max_reg = max_reg_num ();
- while (changed)
+ timevar_pop (TV_REBUILD_JUMP);
+}
+\f
+/* Some old code expects exactly one BARRIER as the NEXT_INSN of a
+ non-fallthru insn. This is not generally true, as multiple barriers
+ may have crept in, or the BARRIER may be separated from the last
+ real insn by one or more NOTEs.
+
+ This simple pass moves barriers and removes duplicates so that the
+ old code is happy.
+ */
+void
+cleanup_barriers (void)
+{
+ rtx insn, next, prev;
+ for (insn = get_insns (); insn; insn = next)
{
- changed = 0;
-
- for (insn = f; insn; insn = next)
+ next = NEXT_INSN (insn);
+ if (GET_CODE (insn) == BARRIER)
{
- rtx reallabelprev;
- rtx temp, temp1, temp2 = NULL_RTX;
- rtx temp4 ATTRIBUTE_UNUSED;
- rtx nlabel;
- int this_is_any_uncondjump;
- int this_is_any_condjump;
- int this_is_onlyjump;
-
- next = NEXT_INSN (insn);
-
- /* See if this is a NOTE_INSN_LOOP_BEG followed by an unconditional
- jump. Try to optimize by duplicating the loop exit test if so.
- This is only safe immediately after regscan, because it uses
- the values of regno_first_uid and regno_last_uid. */
- if (after_regscan && GET_CODE (insn) == NOTE
- && NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG
- && (temp1 = next_nonnote_insn (insn)) != 0
- && any_uncondjump_p (temp1)
- && onlyjump_p (temp1))
- {
- temp = PREV_INSN (insn);
- if (duplicate_loop_exit_test (insn))
- {
- changed = 1;
- next = NEXT_INSN (temp);
- continue;
- }
- }
-
- if (GET_CODE (insn) != JUMP_INSN)
- continue;
-
- this_is_any_condjump = any_condjump_p (insn);
- this_is_any_uncondjump = any_uncondjump_p (insn);
- this_is_onlyjump = onlyjump_p (insn);
-
- /* Tension the labels in dispatch tables. */
-
- if (GET_CODE (PATTERN (insn)) == ADDR_VEC)
- changed |= tension_vector_labels (PATTERN (insn), 0);
- if (GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)
- changed |= tension_vector_labels (PATTERN (insn), 1);
-
- /* See if this jump goes to another jump and redirect if so. */
- nlabel = follow_jumps (JUMP_LABEL (insn));
- if (nlabel != JUMP_LABEL (insn))
- changed |= redirect_jump (insn, nlabel, 1);
-
- if (! optimize || minimal)
- continue;
-
- /* If a dispatch table always goes to the same place,
- get rid of it and replace the insn that uses it. */
-
- if (GET_CODE (PATTERN (insn)) == ADDR_VEC
- || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)
- {
- int i;
- rtx pat = PATTERN (insn);
- int diff_vec_p = GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC;
- int len = XVECLEN (pat, diff_vec_p);
- rtx dispatch = prev_real_insn (insn);
- rtx set;
-
- for (i = 0; i < len; i++)
- if (XEXP (XVECEXP (pat, diff_vec_p, i), 0)
- != XEXP (XVECEXP (pat, diff_vec_p, 0), 0))
- break;
-
- if (i == len
- && dispatch != 0
- && GET_CODE (dispatch) == JUMP_INSN
- && JUMP_LABEL (dispatch) != 0
- /* Don't mess with a casesi insn.
- XXX according to the comment before computed_jump_p(),
- all casesi insns should be a parallel of the jump
- and a USE of a LABEL_REF. */
- && ! ((set = single_set (dispatch)) != NULL
- && (GET_CODE (SET_SRC (set)) == IF_THEN_ELSE))
- && next_real_insn (JUMP_LABEL (dispatch)) == insn)
- {
- redirect_tablejump (dispatch,
- XEXP (XVECEXP (pat, diff_vec_p, 0), 0));
- changed = 1;
- }
- }
-
- reallabelprev = prev_active_insn (JUMP_LABEL (insn));
-
- /* Detect jump to following insn. */
- if (reallabelprev == insn
- && (this_is_any_condjump || this_is_any_uncondjump)
- && this_is_onlyjump)
- {
- next = next_real_insn (JUMP_LABEL (insn));
- delete_jump (insn);
-
- /* Remove the "inactive" but "real" insns (i.e. uses and
- clobbers) in between here and there. */
- temp = insn;
- while ((temp = next_real_insn (temp)) != next)
- delete_insn (temp);
-
- changed = 1;
- continue;
- }
-
- /* Detect a conditional jump going to the same place
- as an immediately following unconditional jump. */
- else if (this_is_any_condjump && this_is_onlyjump
- && (temp = next_active_insn (insn)) != 0
- && simplejump_p (temp)
- && (next_active_insn (JUMP_LABEL (insn))
- == next_active_insn (JUMP_LABEL (temp))))
- {
- /* Don't mess up test coverage analysis. */
- temp2 = temp;
- if (flag_test_coverage && !reload_completed)
- for (temp2 = insn; temp2 != temp; temp2 = NEXT_INSN (temp2))
- if (GET_CODE (temp2) == NOTE && NOTE_LINE_NUMBER (temp2) > 0)
- break;
-
- if (temp2 == temp)
- {
- /* Ensure that we jump to the later of the two labels.
- Consider:
-
- if (test) goto L2;
- goto L1;
- ...
- L1:
- (clobber return-reg)
- L2:
- (use return-reg)
-
- If we leave the goto L1, we'll incorrectly leave
- return-reg dead for TEST true. */
-
- temp2 = next_active_insn (JUMP_LABEL (insn));
- if (!temp2)
- temp2 = get_last_insn ();
- if (GET_CODE (temp2) != CODE_LABEL)
- temp2 = prev_label (temp2);
- if (temp2 != JUMP_LABEL (temp))
- redirect_jump (temp, temp2, 1);
-
- delete_jump (insn);
- changed = 1;
- continue;
- }
- }
-
- /* Detect a conditional jump jumping over an unconditional jump. */
-
- else if (this_is_any_condjump
- && reallabelprev != 0
- && GET_CODE (reallabelprev) == JUMP_INSN
- && prev_active_insn (reallabelprev) == insn
- && no_labels_between_p (insn, reallabelprev)
- && any_uncondjump_p (reallabelprev)
- && onlyjump_p (reallabelprev))
- {
- /* When we invert the unconditional jump, we will be
- decrementing the usage count of its old label.
- Make sure that we don't delete it now because that
- might cause the following code to be deleted. */
- rtx prev_uses = prev_nonnote_insn (reallabelprev);
- rtx prev_label = JUMP_LABEL (insn);
-
- if (prev_label)
- ++LABEL_NUSES (prev_label);
-
- if (invert_jump (insn, JUMP_LABEL (reallabelprev), 1))
- {
- /* It is very likely that if there are USE insns before
- this jump, they hold REG_DEAD notes. These REG_DEAD
- notes are no longer valid due to this optimization,
- and will cause the life-analysis that following passes
- (notably delayed-branch scheduling) to think that
- these registers are dead when they are not.
-
- To prevent this trouble, we just remove the USE insns
- from the insn chain. */
-
- while (prev_uses && GET_CODE (prev_uses) == INSN
- && GET_CODE (PATTERN (prev_uses)) == USE)
- {
- rtx useless = prev_uses;
- prev_uses = prev_nonnote_insn (prev_uses);
- delete_insn (useless);
- }
-
- delete_insn (reallabelprev);
- changed = 1;
- }
-
- /* We can now safely delete the label if it is unreferenced
- since the delete_insn above has deleted the BARRIER. */
- if (prev_label && --LABEL_NUSES (prev_label) == 0)
- delete_insn (prev_label);
-
- next = NEXT_INSN (insn);
- }
+ prev = prev_nonnote_insn (insn);
+ if (GET_CODE (prev) == BARRIER)
+ delete_barrier (insn);
+ else if (prev != PREV_INSN (insn))
+ reorder_insns (insn, insn, prev);
+ }
+ }
+}
+\f
+/* Return the next insn after INSN that is not a NOTE and is in the loop,
+ i.e. when there is no such INSN before NOTE_INSN_LOOP_END return NULL_RTX.
+ This routine does not look inside SEQUENCEs. */
- /* If we have an unconditional jump preceded by a USE, try to put
- the USE before the target and jump there. This simplifies many
- of the optimizations below since we don't have to worry about
- dealing with these USE insns. We only do this if the label
- being branch to already has the identical USE or if code
- never falls through to that label. */
-
- else if (this_is_any_uncondjump
- && (temp = prev_nonnote_insn (insn)) != 0
- && GET_CODE (temp) == INSN
- && GET_CODE (PATTERN (temp)) == USE
- && (temp1 = prev_nonnote_insn (JUMP_LABEL (insn))) != 0
- && (GET_CODE (temp1) == BARRIER
- || (GET_CODE (temp1) == INSN
- && rtx_equal_p (PATTERN (temp), PATTERN (temp1))))
- /* Don't do this optimization if we have a loop containing
- only the USE instruction, and the loop start label has
- a usage count of 1. This is because we will redo this
- optimization everytime through the outer loop, and jump
- opt will never exit. */
- && ! ((temp2 = prev_nonnote_insn (temp)) != 0
- && temp2 == JUMP_LABEL (insn)
- && LABEL_NUSES (temp2) == 1))
- {
- if (GET_CODE (temp1) == BARRIER)
- {
- emit_insn_after (PATTERN (temp), temp1);
- temp1 = NEXT_INSN (temp1);
- }
+static rtx
+next_nonnote_insn_in_loop (rtx insn)
+{
+ while (insn)
+ {
+ insn = NEXT_INSN (insn);
+ if (insn == 0 || GET_CODE (insn) != NOTE)
+ break;
+ if (GET_CODE (insn) == NOTE
+ && NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END)
+ return NULL_RTX;
+ }
- delete_insn (temp);
- redirect_jump (insn, get_label_before (temp1), 1);
- reallabelprev = prev_real_insn (temp1);
- changed = 1;
- next = NEXT_INSN (insn);
- }
+ return insn;
+}
-#ifdef HAVE_trap
- /* Detect a conditional jump jumping over an unconditional trap. */
- if (HAVE_trap
- && this_is_any_condjump && this_is_onlyjump
- && reallabelprev != 0
- && GET_CODE (reallabelprev) == INSN
- && GET_CODE (PATTERN (reallabelprev)) == TRAP_IF
- && TRAP_CONDITION (PATTERN (reallabelprev)) == const_true_rtx
- && prev_active_insn (reallabelprev) == insn
- && no_labels_between_p (insn, reallabelprev)
- && (temp2 = get_condition (insn, &temp4))
- && ((reversed_code = reversed_comparison_code (temp2, insn))
- != UNKNOWN))
- {
- rtx new = gen_cond_trap (reversed_code,
- XEXP (temp2, 0), XEXP (temp2, 1),
- TRAP_CODE (PATTERN (reallabelprev)));
+void
+copy_loop_headers (rtx f)
+{
+ rtx insn, next;
+ /* Now iterate optimizing jumps until nothing changes over one pass. */
+ for (insn = f; insn; insn = next)
+ {
+ rtx temp, temp1;
- if (new)
- {
- emit_insn_before (new, temp4);
- delete_insn (reallabelprev);
- delete_jump (insn);
- changed = 1;
- continue;
- }
- }
- /* Detect a jump jumping to an unconditional trap. */
- else if (HAVE_trap && this_is_onlyjump
- && (temp = next_active_insn (JUMP_LABEL (insn)))
- && GET_CODE (temp) == INSN
- && GET_CODE (PATTERN (temp)) == TRAP_IF
- && (this_is_any_uncondjump
- || (this_is_any_condjump
- && (temp2 = get_condition (insn, &temp4)))))
- {
- rtx tc = TRAP_CONDITION (PATTERN (temp));
+ next = NEXT_INSN (insn);
- if (tc == const_true_rtx
- || (! this_is_any_uncondjump && rtx_equal_p (temp2, tc)))
- {
- rtx new;
- /* Replace an unconditional jump to a trap with a trap. */
- if (this_is_any_uncondjump)
- {
- emit_barrier_after (emit_insn_before (gen_trap (), insn));
- delete_jump (insn);
- changed = 1;
- continue;
- }
- new = gen_cond_trap (GET_CODE (temp2), XEXP (temp2, 0),
- XEXP (temp2, 1),
- TRAP_CODE (PATTERN (temp)));
- if (new)
- {
- emit_insn_before (new, temp4);
- delete_jump (insn);
- changed = 1;
- continue;
- }
- }
- /* If the trap condition and jump condition are mutually
- exclusive, redirect the jump to the following insn. */
- else if (GET_RTX_CLASS (GET_CODE (tc)) == '<'
- && this_is_any_condjump
- && swap_condition (GET_CODE (temp2)) == GET_CODE (tc)
- && rtx_equal_p (XEXP (tc, 0), XEXP (temp2, 0))
- && rtx_equal_p (XEXP (tc, 1), XEXP (temp2, 1))
- && redirect_jump (insn, get_label_after (temp), 1))
- {
- changed = 1;
- continue;
- }
- }
-#endif
- else
+ /* See if this is a NOTE_INSN_LOOP_BEG followed by an unconditional
+ jump. Try to optimize by duplicating the loop exit test if so.
+ This is only safe immediately after regscan, because it uses
+ the values of regno_first_uid and regno_last_uid. */
+ if (GET_CODE (insn) == NOTE
+ && NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG
+ && (temp1 = next_nonnote_insn_in_loop (insn)) != 0
+ && any_uncondjump_p (temp1) && onlyjump_p (temp1))
+ {
+ temp = PREV_INSN (insn);
+ if (duplicate_loop_exit_test (insn))
{
- /* Now that the jump has been tensioned,
- try cross jumping: check for identical code
- before the jump and before its target label. */
-
- /* First, cross jumping of conditional jumps: */
-
- if (cross_jump && condjump_p (insn))
- {
- rtx newjpos, newlpos;
- rtx x = prev_real_insn (JUMP_LABEL (insn));
-
- /* A conditional jump may be crossjumped
- only if the place it jumps to follows
- an opposing jump that comes back here. */
-
- if (x != 0 && ! jump_back_p (x, insn))
- /* We have no opposing jump;
- cannot cross jump this insn. */
- x = 0;
-
- newjpos = 0;
- /* TARGET is nonzero if it is ok to cross jump
- to code before TARGET. If so, see if matches. */
- if (x != 0)
- find_cross_jump (insn, x, 2,
- &newjpos, &newlpos);
-
- if (newjpos != 0)
- {
- do_cross_jump (insn, newjpos, newlpos);
- /* Make the old conditional jump
- into an unconditional one. */
- PATTERN (insn) = gen_jump (JUMP_LABEL (insn));
- INSN_CODE (insn) = -1;
- emit_barrier_after (insn);
- /* Add to jump_chain unless this is a new label
- whose UID is too large. */
- if (INSN_UID (JUMP_LABEL (insn)) < max_jump_chain)
- {
- jump_chain[INSN_UID (insn)]
- = jump_chain[INSN_UID (JUMP_LABEL (insn))];
- jump_chain[INSN_UID (JUMP_LABEL (insn))] = insn;
- }
- changed = 1;
- next = insn;
- }
- }
-
- /* Cross jumping of unconditional jumps:
- a few differences. */
-
- if (cross_jump && simplejump_p (insn))
- {
- rtx newjpos, newlpos;
- rtx target;
-
- newjpos = 0;
-
- /* TARGET is nonzero if it is ok to cross jump
- to code before TARGET. If so, see if matches. */
- find_cross_jump (insn, JUMP_LABEL (insn), 1,
- &newjpos, &newlpos);
-
- /* If cannot cross jump to code before the label,
- see if we can cross jump to another jump to
- the same label. */
- /* Try each other jump to this label. */
- if (INSN_UID (JUMP_LABEL (insn)) < max_uid)
- for (target = jump_chain[INSN_UID (JUMP_LABEL (insn))];
- target != 0 && newjpos == 0;
- target = jump_chain[INSN_UID (target)])
- if (target != insn
- && JUMP_LABEL (target) == JUMP_LABEL (insn)
- /* Ignore TARGET if it's deleted. */
- && ! INSN_DELETED_P (target))
- find_cross_jump (insn, target, 2,
- &newjpos, &newlpos);
-
- if (newjpos != 0)
- {
- do_cross_jump (insn, newjpos, newlpos);
- changed = 1;
- next = insn;
- }
- }
-
- /* This code was dead in the previous jump.c! */
- if (cross_jump && GET_CODE (PATTERN (insn)) == RETURN)
- {
- /* Return insns all "jump to the same place"
- so we can cross-jump between any two of them. */
-
- rtx newjpos, newlpos, target;
-
- newjpos = 0;
-
- /* If cannot cross jump to code before the label,
- see if we can cross jump to another jump to
- the same label. */
- /* Try each other jump to this label. */
- for (target = jump_chain[0];
- target != 0 && newjpos == 0;
- target = jump_chain[INSN_UID (target)])
- if (target != insn
- && ! INSN_DELETED_P (target)
- && GET_CODE (PATTERN (target)) == RETURN)
- find_cross_jump (insn, target, 2,
- &newjpos, &newlpos);
-
- if (newjpos != 0)
- {
- do_cross_jump (insn, newjpos, newlpos);
- changed = 1;
- next = insn;
- }
- }
+ next = NEXT_INSN (temp);
}
}
-
- first = 0;
}
+}
+void
+purge_line_number_notes (rtx f)
+{
+ rtx last_note = 0;
+ rtx insn;
/* Delete extraneous line number notes.
Note that two consecutive notes for different lines are not really
extraneous. There should be some indication where that line belonged,
even if it became empty. */
- {
- rtx last_note = 0;
-
- for (insn = f; insn; insn = NEXT_INSN (insn))
- if (GET_CODE (insn) == NOTE)
- {
- if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_FUNCTION_BEG)
- /* Any previous line note was for the prologue; gdb wants a new
- note after the prologue even if it is for the same line. */
- last_note = NULL_RTX;
- else if (NOTE_LINE_NUMBER (insn) >= 0)
- {
- /* Delete this note if it is identical to previous note. */
- if (last_note
- && NOTE_SOURCE_FILE (insn) == NOTE_SOURCE_FILE (last_note)
- && NOTE_LINE_NUMBER (insn) == NOTE_LINE_NUMBER (last_note))
- {
- delete_insn (insn);
- continue;
- }
-
- last_note = insn;
- }
- }
- }
+ for (insn = f; insn; insn = NEXT_INSN (insn))
+ if (GET_CODE (insn) == NOTE)
+ {
+ if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_FUNCTION_BEG)
+ /* Any previous line note was for the prologue; gdb wants a new
+ note after the prologue even if it is for the same line. */
+ last_note = NULL_RTX;
+ else if (NOTE_LINE_NUMBER (insn) >= 0)
+ {
+ /* Delete this note if it is identical to previous note. */
+ if (last_note
+ && NOTE_SOURCE_FILE (insn) == NOTE_SOURCE_FILE (last_note)
+ && NOTE_LINE_NUMBER (insn) == NOTE_LINE_NUMBER (last_note))
+ {
+ delete_related_insns (insn);
+ continue;
+ }
-end:
- /* Clean up. */
- free (jump_chain);
- jump_chain = 0;
+ last_note = insn;
+ }
+ }
}
\f
/* Initialize LABEL_NUSES and JUMP_LABEL fields. Delete any REG_LABEL
notes whose labels don't occur in the insn any more. Returns the
largest INSN_UID found. */
-static int
-init_label_info (f)
- rtx f;
-{
- int largest_uid = 0;
- rtx insn;
-
- for (insn = f; insn; insn = NEXT_INSN (insn))
- {
- if (GET_CODE (insn) == CODE_LABEL)
- LABEL_NUSES (insn) = (LABEL_PRESERVE_P (insn) != 0);
- else if (GET_CODE (insn) == JUMP_INSN)
- JUMP_LABEL (insn) = 0;
- else if (GET_CODE (insn) == INSN || GET_CODE (insn) == CALL_INSN)
- {
- rtx note, next;
-
- for (note = REG_NOTES (insn); note; note = next)
- {
- next = XEXP (note, 1);
- if (REG_NOTE_KIND (note) == REG_LABEL
- && ! reg_mentioned_p (XEXP (note, 0), PATTERN (insn)))
- remove_note (insn, note);
- }
- }
- if (INSN_UID (insn) > largest_uid)
- largest_uid = INSN_UID (insn);
- }
-
- return largest_uid;
-}
-
-/* Delete insns following barriers, up to next label.
-
- Also delete no-op jumps created by gcse. */
-
static void
-delete_barrier_successors (f)
- rtx f;
+init_label_info (rtx f)
{
rtx insn;
- rtx set;
-
- for (insn = f; insn;)
- {
- if (GET_CODE (insn) == BARRIER)
- {
- insn = NEXT_INSN (insn);
- never_reached_warning (insn);
-
- while (insn != 0 && GET_CODE (insn) != CODE_LABEL)
- {
- if (GET_CODE (insn) == JUMP_INSN)
- {
- /* Detect when we're deleting a tablejump; get rid of
- the jump table as well. */
- rtx next1 = next_nonnote_insn (insn);
- rtx next2 = next1 ? next_nonnote_insn (next1) : 0;
- if (next2 && GET_CODE (next1) == CODE_LABEL
- && GET_CODE (next2) == JUMP_INSN
- && (GET_CODE (PATTERN (next2)) == ADDR_VEC
- || GET_CODE (PATTERN (next2)) == ADDR_DIFF_VEC))
- {
- delete_insn (insn);
- insn = next2;
- }
- else
- insn = delete_insn (insn);
- }
- else if (GET_CODE (insn) == NOTE
- && NOTE_LINE_NUMBER (insn) != NOTE_INSN_FUNCTION_END)
- insn = NEXT_INSN (insn);
- else
- insn = delete_insn (insn);
- }
- /* INSN is now the code_label. */
- }
-
- /* Also remove (set (pc) (pc)) insns which can be created by
- gcse. We eliminate such insns now to avoid having them
- cause problems later. */
- else if (GET_CODE (insn) == JUMP_INSN
- && (set = pc_set (insn)) != NULL
- && SET_SRC (set) == pc_rtx
- && SET_DEST (set) == pc_rtx
- && onlyjump_p (insn))
- insn = delete_insn (insn);
+ for (insn = f; insn; insn = NEXT_INSN (insn))
+ if (GET_CODE (insn) == CODE_LABEL)
+ LABEL_NUSES (insn) = (LABEL_PRESERVE_P (insn) != 0);
+ else if (GET_CODE (insn) == JUMP_INSN)
+ JUMP_LABEL (insn) = 0;
+ else if (GET_CODE (insn) == INSN || GET_CODE (insn) == CALL_INSN)
+ {
+ rtx note, next;
- else
- insn = NEXT_INSN (insn);
- }
+ for (note = REG_NOTES (insn); note; note = next)
+ {
+ next = XEXP (note, 1);
+ if (REG_NOTE_KIND (note) == REG_LABEL
+ && ! reg_mentioned_p (XEXP (note, 0), PATTERN (insn)))
+ remove_note (insn, note);
+ }
+ }
}
/* Mark the label each jump jumps to.
- Combine consecutive labels, and count uses of labels.
-
- For each label, make a chain (using `jump_chain')
- of all the *unconditional* jumps that jump to it;
- also make a chain of all returns.
-
- CROSS_JUMP indicates whether we are doing cross jumping
- and if we are whether we will be paying attention to
- death notes or not. */
+ Combine consecutive labels, and count uses of labels. */
static void
-mark_all_labels (f, cross_jump)
- rtx f;
- int cross_jump;
+mark_all_labels (rtx f)
{
rtx insn;
if (GET_CODE (insn) == CALL_INSN
&& GET_CODE (PATTERN (insn)) == CALL_PLACEHOLDER)
{
- mark_all_labels (XEXP (PATTERN (insn), 0), cross_jump);
- mark_all_labels (XEXP (PATTERN (insn), 1), cross_jump);
- mark_all_labels (XEXP (PATTERN (insn), 2), cross_jump);
+ mark_all_labels (XEXP (PATTERN (insn), 0));
+ mark_all_labels (XEXP (PATTERN (insn), 1));
+ mark_all_labels (XEXP (PATTERN (insn), 2));
/* Canonicalize the tail recursion label attached to the
CALL_PLACEHOLDER insn. */
{
rtx label_ref = gen_rtx_LABEL_REF (VOIDmode,
XEXP (PATTERN (insn), 3));
- mark_jump_label (label_ref, insn, cross_jump, 0);
+ mark_jump_label (label_ref, insn, 0);
XEXP (PATTERN (insn), 3) = XEXP (label_ref, 0);
}
continue;
}
- mark_jump_label (PATTERN (insn), insn, cross_jump, 0);
+ mark_jump_label (PATTERN (insn), insn, 0);
if (! INSN_DELETED_P (insn) && GET_CODE (insn) == JUMP_INSN)
{
/* When we know the LABEL_REF contained in a REG used in
rtx label_ref = gen_rtx_LABEL_REF (VOIDmode,
XEXP (label_note, 0));
- mark_jump_label (label_ref, insn, cross_jump, 0);
+ mark_jump_label (label_ref, insn, 0);
XEXP (label_note, 0) = XEXP (label_ref, 0);
JUMP_LABEL (insn) = XEXP (label_note, 0);
}
}
- if (JUMP_LABEL (insn) != 0 && simplejump_p (insn))
- {
- jump_chain[INSN_UID (insn)]
- = jump_chain[INSN_UID (JUMP_LABEL (insn))];
- jump_chain[INSN_UID (JUMP_LABEL (insn))] = insn;
- }
- if (GET_CODE (PATTERN (insn)) == RETURN)
- {
- jump_chain[INSN_UID (insn)] = jump_chain[0];
- jump_chain[0] = insn;
- }
}
}
}
-/* Delete all labels already not referenced.
- Also find and return the last insn. */
-
-static rtx
-delete_unreferenced_labels (f)
- rtx f;
-{
- rtx final = NULL_RTX;
- rtx insn;
-
- for (insn = f; insn;)
- {
- if (GET_CODE (insn) == CODE_LABEL
- && LABEL_NUSES (insn) == 0
- && LABEL_ALTERNATE_NAME (insn) == NULL)
- insn = delete_insn (insn);
- else
- {
- final = insn;
- insn = NEXT_INSN (insn);
- }
- }
-
- return final;
-}
-
-/* Delete various simple forms of moves which have no necessary
- side effect. */
-
-static void
-delete_noop_moves (f)
- rtx f;
-{
- rtx insn, next;
-
- for (insn = f; insn;)
- {
- next = NEXT_INSN (insn);
-
- if (GET_CODE (insn) == INSN)
- {
- register rtx body = PATTERN (insn);
-
- /* Detect and delete no-op move instructions
- resulting from not allocating a parameter in a register. */
-
- if (GET_CODE (body) == SET && set_noop_p (body))
- delete_computation (insn);
-
- /* Detect and ignore no-op move instructions
- resulting from smart or fortuitous register allocation. */
-
- else if (GET_CODE (body) == SET)
- {
- int sreg = true_regnum (SET_SRC (body));
- int dreg = true_regnum (SET_DEST (body));
-
- if (sreg == dreg && sreg >= 0)
- delete_insn (insn);
- else if (sreg >= 0 && dreg >= 0)
- {
- rtx trial;
- rtx tem = find_equiv_reg (NULL_RTX, insn, 0,
- sreg, NULL, dreg,
- GET_MODE (SET_SRC (body)));
-
- if (tem != 0
- && GET_MODE (tem) == GET_MODE (SET_DEST (body)))
- {
- /* DREG may have been the target of a REG_DEAD note in
- the insn which makes INSN redundant. If so, reorg
- would still think it is dead. So search for such a
- note and delete it if we find it. */
- if (! find_regno_note (insn, REG_UNUSED, dreg))
- for (trial = prev_nonnote_insn (insn);
- trial && GET_CODE (trial) != CODE_LABEL;
- trial = prev_nonnote_insn (trial))
- if (find_regno_note (trial, REG_DEAD, dreg))
- {
- remove_death (dreg, trial);
- break;
- }
-
- /* Deleting insn could lose a death-note for SREG. */
- if ((trial = find_regno_note (insn, REG_DEAD, sreg)))
- {
- /* Change this into a USE so that we won't emit
- code for it, but still can keep the note. */
- PATTERN (insn)
- = gen_rtx_USE (VOIDmode, XEXP (trial, 0));
- INSN_CODE (insn) = -1;
- /* Remove all reg notes but the REG_DEAD one. */
- REG_NOTES (insn) = trial;
- XEXP (trial, 1) = NULL_RTX;
- }
- else
- delete_insn (insn);
- }
- }
- else if (dreg >= 0 && CONSTANT_P (SET_SRC (body))
- && find_equiv_reg (SET_SRC (body), insn, 0, dreg,
- NULL, 0, GET_MODE (SET_DEST (body))))
- {
- /* This handles the case where we have two consecutive
- assignments of the same constant to pseudos that didn't
- get a hard reg. Each SET from the constant will be
- converted into a SET of the spill register and an
- output reload will be made following it. This produces
- two loads of the same constant into the same spill
- register. */
-
- rtx in_insn = insn;
-
- /* Look back for a death note for the first reg.
- If there is one, it is no longer accurate. */
- while (in_insn && GET_CODE (in_insn) != CODE_LABEL)
- {
- if ((GET_CODE (in_insn) == INSN
- || GET_CODE (in_insn) == JUMP_INSN)
- && find_regno_note (in_insn, REG_DEAD, dreg))
- {
- remove_death (dreg, in_insn);
- break;
- }
- in_insn = PREV_INSN (in_insn);
- }
-
- /* Delete the second load of the value. */
- delete_insn (insn);
- }
- }
- else if (GET_CODE (body) == PARALLEL)
- {
- /* If each part is a set between two identical registers or
- a USE or CLOBBER, delete the insn. */
- int i, sreg, dreg;
- rtx tem;
-
- for (i = XVECLEN (body, 0) - 1; i >= 0; i--)
- {
- tem = XVECEXP (body, 0, i);
- if (GET_CODE (tem) == USE || GET_CODE (tem) == CLOBBER)
- continue;
-
- if (GET_CODE (tem) != SET
- || (sreg = true_regnum (SET_SRC (tem))) < 0
- || (dreg = true_regnum (SET_DEST (tem))) < 0
- || dreg != sreg)
- break;
- }
-
- if (i < 0)
- delete_insn (insn);
- }
- }
- insn = next;
- }
-}
-
/* LOOP_START is a NOTE_INSN_LOOP_BEG note that is followed by an unconditional
jump. Assume that this unconditional jump is to the exit test code. If
the code is sufficiently simple, make a copy of it before INSN,
values of regno_first_uid and regno_last_uid. */
static int
-duplicate_loop_exit_test (loop_start)
- rtx loop_start;
+duplicate_loop_exit_test (rtx loop_start)
{
rtx insn, set, reg, p, link;
rtx copy = 0, first_copy = 0;
int num_insns = 0;
- rtx exitcode = NEXT_INSN (JUMP_LABEL (next_nonnote_insn (loop_start)));
+ rtx exitcode
+ = NEXT_INSN (JUMP_LABEL (next_nonnote_insn_in_loop (loop_start)));
rtx lastexit;
int max_reg = max_reg_num ();
rtx *reg_map = 0;
+ rtx loop_pre_header_label;
/* Scan the exit code. We do not perform this optimization if any insn:
is a CODE_LABEL
has a REG_RETVAL or REG_LIBCALL note (hard to adjust)
is a NOTE_INSN_LOOP_BEG because this means we have a nested loop
- is a NOTE_INSN_BLOCK_{BEG,END} because duplicating these notes
- is not valid.
We also do not do this if we find an insn with ASM_OPERANDS. While
this restriction should not be necessary, copying an insn with
case CALL_INSN:
return 0;
case NOTE:
- /* We could be in front of the wrong NOTE_INSN_LOOP_END if there is
- a jump immediately after the loop start that branches outside
- the loop but within an outer loop, near the exit test.
- If we copied this exit test and created a phony
- NOTE_INSN_LOOP_VTOP, this could make instructions immediately
- before the exit test look like these could be safely moved
- out of the loop even if they actually may be never executed.
- This can be avoided by checking here for NOTE_INSN_LOOP_CONT. */
-
- if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG
- || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_CONT)
- return 0;
if (optimize < 2
&& (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG
break;
case JUMP_INSN:
case INSN:
- /* The code below would grossly mishandle REG_WAS_0 notes,
- so get rid of them here. */
- while ((p = find_reg_note (insn, REG_WAS_0, NULL_RTX)) != 0)
- remove_note (insn, p);
if (++num_insns > 20
|| find_reg_note (insn, REG_RETVAL, NULL_RTX)
|| find_reg_note (insn, REG_LIBCALL, NULL_RTX))
/* We can do the replacement. Allocate reg_map if this is the
first replacement we found. */
if (reg_map == 0)
- reg_map = (rtx *) xcalloc (max_reg, sizeof (rtx));
+ reg_map = xcalloc (max_reg, sizeof (rtx));
REG_LOOP_TEST_P (reg) = 1;
reg_map[REGNO (reg)] = gen_reg_rtx (GET_MODE (reg));
}
}
+ loop_pre_header_label = gen_label_rtx ();
/* Now copy each insn. */
for (insn = exitcode; insn != lastexit; insn = NEXT_INSN (insn))
if (reg_map)
replace_regs (PATTERN (copy), reg_map, max_reg, 1);
- mark_jump_label (PATTERN (copy), copy, 0, 0);
+ mark_jump_label (PATTERN (copy), copy, 0);
+ INSN_LOCATOR (copy) = INSN_LOCATOR (insn);
/* Copy all REG_NOTES except REG_LABEL since mark_jump_label will
make them. */
case JUMP_INSN:
copy = emit_jump_insn_before (copy_insn (PATTERN (insn)),
loop_start);
+ INSN_LOCATOR (copy) = INSN_LOCATOR (insn);
if (reg_map)
replace_regs (PATTERN (copy), reg_map, max_reg, 1);
- mark_jump_label (PATTERN (copy), copy, 0, 0);
+ mark_jump_label (PATTERN (copy), copy, 0);
if (REG_NOTES (insn))
{
REG_NOTES (copy) = copy_insn_1 (REG_NOTES (insn));
/* The jump_insn after loop_start should be followed
by barrier and loopback label. */
if (prev_nonnote_insn (label)
- && (PREV_INSN (prev_nonnote_insn (label))
- == NEXT_INSN (loop_start)))
- predict_insn_def (copy, PRED_LOOP_HEADER, TAKEN);
+ && (prev_nonnote_insn (prev_nonnote_insn (label))
+ == next_nonnote_insn (loop_start)))
+ {
+ predict_insn_def (copy, PRED_LOOP_HEADER, TAKEN);
+ /* To keep pre-header, we need to redirect all loop
+ entrances before the LOOP_BEG note. */
+ redirect_jump (copy, loop_pre_header_label, 0);
+ }
else
predict_insn_def (copy, PRED_LOOP_HEADER, NOT_TAKEN);
}
}
- /* If this is a simple jump, add it to the jump chain. */
-
- if (INSN_UID (copy) < max_jump_chain && JUMP_LABEL (copy)
- && simplejump_p (copy))
- {
- jump_chain[INSN_UID (copy)]
- = jump_chain[INSN_UID (JUMP_LABEL (copy))];
- jump_chain[INSN_UID (JUMP_LABEL (copy))] = copy;
- }
break;
default:
if (! first_copy)
first_copy = copy;
- mark_jump_label (PATTERN (copy), copy, 0, 0);
- if (INSN_UID (copy) < max_jump_chain
- && INSN_UID (JUMP_LABEL (copy)) < max_jump_chain)
- {
- jump_chain[INSN_UID (copy)]
- = jump_chain[INSN_UID (JUMP_LABEL (copy))];
- jump_chain[INSN_UID (JUMP_LABEL (copy))] = copy;
- }
+ mark_jump_label (PATTERN (copy), copy, 0);
emit_barrier_before (loop_start);
}
+ emit_label_before (loop_pre_header_label, loop_start);
+
/* Now scan from the first insn we copied to the last insn we copied
(copy) for new pseudo registers. Do this after the code to jump to
the end label since that might create a new pseudo too. */
/* Mark the exit code as the virtual top of the converted loop. */
emit_note_before (NOTE_INSN_LOOP_VTOP, exitcode);
- delete_insn (next_nonnote_insn (loop_start));
+ delete_related_insns (next_nonnote_insn (loop_start));
/* Clean up. */
if (reg_map)
}
\f
/* Move all block-beg, block-end, loop-beg, loop-cont, loop-vtop, loop-end,
- notes between START and END out before START. Assume that END is not
- such a note. START may be such a note. Returns the value of the new
- starting insn, which may be different if the original start was such a
- note. */
+ notes between START and END out before START. START and END may be such
+ notes. Returns the values of the new starting and ending insns, which
+ may be different if the original ones were such notes.
+ Return true if there were only such notes and no real instructions. */
-rtx
-squeeze_notes (start, end)
- rtx start, end;
+bool
+squeeze_notes (rtx* startp, rtx* endp)
{
+ rtx start = *startp;
+ rtx end = *endp;
+
rtx insn;
rtx next;
+ rtx last = NULL;
+ rtx past_end = NEXT_INSN (end);
- for (insn = start; insn != end; insn = next)
+ for (insn = start; insn != past_end; insn = next)
{
next = NEXT_INSN (insn);
if (GET_CODE (insn) == NOTE
PREV_INSN (next) = prev;
}
}
+ else
+ last = insn;
}
- return start;
-}
-\f
-/* Compare the instructions before insn E1 with those before E2
- to find an opportunity for cross jumping.
- (This means detecting identical sequences of insns followed by
- jumps to the same place, or followed by a label and a jump
- to that label, and replacing one with a jump to the other.)
-
- Assume E1 is a jump that jumps to label E2
- (that is not always true but it might as well be).
- Find the longest possible equivalent sequences
- and store the first insns of those sequences into *F1 and *F2.
- Store zero there if no equivalent preceding instructions are found.
-
- We give up if we find a label in stream 1.
- Actually we could transfer that label into stream 2. */
-
-static void
-find_cross_jump (e1, e2, minimum, f1, f2)
- rtx e1, e2;
- int minimum;
- rtx *f1, *f2;
-{
- register rtx i1 = e1, i2 = e2;
- register rtx p1, p2;
- int lose = 0;
-
- rtx last1 = 0, last2 = 0;
- rtx afterlast1 = 0, afterlast2 = 0;
-
- *f1 = 0;
- *f2 = 0;
-
- while (1)
- {
- i1 = prev_nonnote_insn (i1);
-
- i2 = PREV_INSN (i2);
- while (i2 && (GET_CODE (i2) == NOTE || GET_CODE (i2) == CODE_LABEL))
- i2 = PREV_INSN (i2);
-
- if (i1 == 0)
- break;
-
- /* Don't allow the range of insns preceding E1 or E2
- to include the other (E2 or E1). */
- if (i2 == e1 || i1 == e2)
- break;
-
- /* If we will get to this code by jumping, those jumps will be
- tensioned to go directly to the new label (before I2),
- so this cross-jumping won't cost extra. So reduce the minimum. */
- if (GET_CODE (i1) == CODE_LABEL)
- {
- --minimum;
- break;
- }
-
- if (i2 == 0 || GET_CODE (i1) != GET_CODE (i2))
- break;
-
- p1 = PATTERN (i1);
- p2 = PATTERN (i2);
-
- /* If this is a CALL_INSN, compare register usage information.
- If we don't check this on stack register machines, the two
- CALL_INSNs might be merged leaving reg-stack.c with mismatching
- numbers of stack registers in the same basic block.
- If we don't check this on machines with delay slots, a delay slot may
- be filled that clobbers a parameter expected by the subroutine.
-
- ??? We take the simple route for now and assume that if they're
- equal, they were constructed identically. */
-
- if (GET_CODE (i1) == CALL_INSN
- && ! rtx_equal_p (CALL_INSN_FUNCTION_USAGE (i1),
- CALL_INSN_FUNCTION_USAGE (i2)))
- lose = 1;
-
-#ifdef STACK_REGS
- /* If cross_jump_death_matters is not 0, the insn's mode
- indicates whether or not the insn contains any stack-like
- regs. */
-
- if (!lose && cross_jump_death_matters && stack_regs_mentioned (i1))
- {
- /* If register stack conversion has already been done, then
- death notes must also be compared before it is certain that
- the two instruction streams match. */
-
- rtx note;
- HARD_REG_SET i1_regset, i2_regset;
-
- CLEAR_HARD_REG_SET (i1_regset);
- CLEAR_HARD_REG_SET (i2_regset);
-
- for (note = REG_NOTES (i1); note; note = XEXP (note, 1))
- if (REG_NOTE_KIND (note) == REG_DEAD
- && STACK_REG_P (XEXP (note, 0)))
- SET_HARD_REG_BIT (i1_regset, REGNO (XEXP (note, 0)));
-
- for (note = REG_NOTES (i2); note; note = XEXP (note, 1))
- if (REG_NOTE_KIND (note) == REG_DEAD
- && STACK_REG_P (XEXP (note, 0)))
- SET_HARD_REG_BIT (i2_regset, REGNO (XEXP (note, 0)));
-
- GO_IF_HARD_REG_EQUAL (i1_regset, i2_regset, done);
-
- lose = 1;
-
- done:
- ;
- }
-#endif
-
- /* Don't allow old-style asm or volatile extended asms to be accepted
- for cross jumping purposes. It is conceptually correct to allow
- them, since cross-jumping preserves the dynamic instruction order
- even though it is changing the static instruction order. However,
- if an asm is being used to emit an assembler pseudo-op, such as
- the MIPS `.set reorder' pseudo-op, then the static instruction order
- matters and it must be preserved. */
- if (GET_CODE (p1) == ASM_INPUT || GET_CODE (p2) == ASM_INPUT
- || (GET_CODE (p1) == ASM_OPERANDS && MEM_VOLATILE_P (p1))
- || (GET_CODE (p2) == ASM_OPERANDS && MEM_VOLATILE_P (p2)))
- lose = 1;
-
- if (lose || GET_CODE (p1) != GET_CODE (p2)
- || ! rtx_renumbered_equal_p (p1, p2))
- {
- /* The following code helps take care of G++ cleanups. */
- rtx equiv1;
- rtx equiv2;
-
- if (!lose && GET_CODE (p1) == GET_CODE (p2)
- && ((equiv1 = find_reg_note (i1, REG_EQUAL, NULL_RTX)) != 0
- || (equiv1 = find_reg_note (i1, REG_EQUIV, NULL_RTX)) != 0)
- && ((equiv2 = find_reg_note (i2, REG_EQUAL, NULL_RTX)) != 0
- || (equiv2 = find_reg_note (i2, REG_EQUIV, NULL_RTX)) != 0)
- /* If the equivalences are not to a constant, they may
- reference pseudos that no longer exist, so we can't
- use them. */
- && CONSTANT_P (XEXP (equiv1, 0))
- && rtx_equal_p (XEXP (equiv1, 0), XEXP (equiv2, 0)))
- {
- rtx s1 = single_set (i1);
- rtx s2 = single_set (i2);
- if (s1 != 0 && s2 != 0
- && rtx_renumbered_equal_p (SET_DEST (s1), SET_DEST (s2)))
- {
- validate_change (i1, &SET_SRC (s1), XEXP (equiv1, 0), 1);
- validate_change (i2, &SET_SRC (s2), XEXP (equiv2, 0), 1);
- if (! rtx_renumbered_equal_p (p1, p2))
- cancel_changes (0);
- else if (apply_change_group ())
- goto win;
- }
- }
-
- /* Insns fail to match; cross jumping is limited to the following
- insns. */
-
-#ifdef HAVE_cc0
- /* Don't allow the insn after a compare to be shared by
- cross-jumping unless the compare is also shared.
- Here, if either of these non-matching insns is a compare,
- exclude the following insn from possible cross-jumping. */
- if (sets_cc0_p (p1) || sets_cc0_p (p2))
- last1 = afterlast1, last2 = afterlast2, ++minimum;
-#endif
-
- /* If cross-jumping here will feed a jump-around-jump
- optimization, this jump won't cost extra, so reduce
- the minimum. */
- if (GET_CODE (i1) == JUMP_INSN
- && JUMP_LABEL (i1)
- && prev_real_insn (JUMP_LABEL (i1)) == e1)
- --minimum;
- break;
- }
-
- win:
- if (GET_CODE (p1) != USE && GET_CODE (p1) != CLOBBER)
- {
- /* Ok, this insn is potentially includable in a cross-jump here. */
- afterlast1 = last1, afterlast2 = last2;
- last1 = i1, last2 = i2, --minimum;
- }
- }
-
- if (minimum <= 0 && last1 != 0 && last1 != e1)
- *f1 = last1, *f2 = last2;
-}
-
-static void
-do_cross_jump (insn, newjpos, newlpos)
- rtx insn, newjpos, newlpos;
-{
- /* Find an existing label at this point
- or make a new one if there is none. */
- register rtx label = get_label_before (newlpos);
-
- /* Make the same jump insn jump to the new point. */
- if (GET_CODE (PATTERN (insn)) == RETURN)
- {
- /* Remove from jump chain of returns. */
- delete_from_jump_chain (insn);
- /* Change the insn. */
- PATTERN (insn) = gen_jump (label);
- INSN_CODE (insn) = -1;
- JUMP_LABEL (insn) = label;
- LABEL_NUSES (label)++;
- /* Add to new the jump chain. */
- if (INSN_UID (label) < max_jump_chain
- && INSN_UID (insn) < max_jump_chain)
- {
- jump_chain[INSN_UID (insn)] = jump_chain[INSN_UID (label)];
- jump_chain[INSN_UID (label)] = insn;
- }
- }
- else
- redirect_jump (insn, label, 1);
+ /* There were no real instructions. */
+ if (start == past_end)
+ return true;
- /* Delete the matching insns before the jump. Also, remove any REG_EQUAL
- or REG_EQUIV note in the NEWLPOS stream that isn't also present in
- the NEWJPOS stream. */
+ end = last;
- while (newjpos != insn)
- {
- rtx lnote;
-
- for (lnote = REG_NOTES (newlpos); lnote; lnote = XEXP (lnote, 1))
- if ((REG_NOTE_KIND (lnote) == REG_EQUAL
- || REG_NOTE_KIND (lnote) == REG_EQUIV)
- && ! find_reg_note (newjpos, REG_EQUAL, XEXP (lnote, 0))
- && ! find_reg_note (newjpos, REG_EQUIV, XEXP (lnote, 0)))
- remove_note (newlpos, lnote);
-
- delete_insn (newjpos);
- newjpos = next_real_insn (newjpos);
- newlpos = next_real_insn (newlpos);
- }
+ *startp = start;
+ *endp = end;
+ return false;
}
\f
/* Return the label before INSN, or put a new label there. */
rtx
-get_label_before (insn)
- rtx insn;
+get_label_before (rtx insn)
{
rtx label;
/* Return the label after INSN, or put a new label there. */
rtx
-get_label_after (insn)
- rtx insn;
+get_label_after (rtx insn)
{
rtx label;
return label;
}
\f
-/* Return 1 if INSN is a jump that jumps to right after TARGET
- only on the condition that TARGET itself would drop through.
- Assumes that TARGET is a conditional jump. */
-
-static int
-jump_back_p (insn, target)
- rtx insn, target;
-{
- rtx cinsn, ctarget;
- enum rtx_code codei, codet;
- rtx set, tset;
-
- if (! any_condjump_p (insn)
- || any_uncondjump_p (target)
- || target != prev_real_insn (JUMP_LABEL (insn)))
- return 0;
- set = pc_set (insn);
- tset = pc_set (target);
-
- cinsn = XEXP (SET_SRC (set), 0);
- ctarget = XEXP (SET_SRC (tset), 0);
-
- codei = GET_CODE (cinsn);
- codet = GET_CODE (ctarget);
-
- if (XEXP (SET_SRC (set), 1) == pc_rtx)
- {
- codei = reversed_comparison_code (cinsn, insn);
- if (codei == UNKNOWN)
- return 0;
- }
-
- if (XEXP (SET_SRC (tset), 2) == pc_rtx)
- {
- codet = reversed_comparison_code (ctarget, target);
- if (codei == UNKNOWN)
- return 0;
- }
-
- return (codei == codet
- && rtx_renumbered_equal_p (XEXP (cinsn, 0), XEXP (ctarget, 0))
- && rtx_renumbered_equal_p (XEXP (cinsn, 1), XEXP (ctarget, 1)));
-}
-\f
-/* Given a comparison (CODE ARG0 ARG1), inside a insn, INSN, return an code
+/* Given a comparison (CODE ARG0 ARG1), inside an insn, INSN, return a code
of reversed comparison if it is possible to do so. Otherwise return UNKNOWN.
UNKNOWN may be returned in case we are having CC_MODE compare and we don't
know whether it's source is floating point or integer comparison. Machine
description should define REVERSIBLE_CC_MODE and REVERSE_CONDITION macros
to help this function avoid overhead in these cases. */
enum rtx_code
-reversed_comparison_code_parts (code, arg0, arg1, insn)
- rtx insn, arg0, arg1;
- enum rtx_code code;
+reversed_comparison_code_parts (enum rtx_code code, rtx arg0, rtx arg1, rtx insn)
{
enum machine_mode mode;
&& REVERSIBLE_CC_MODE (mode))
{
#ifdef REVERSE_CONDITION
- return REVERSE_CONDITION (code, mode);
+ return REVERSE_CONDITION (code, mode);
#endif
- return reverse_condition (code);
- }
+ return reverse_condition (code);
+ }
#endif
- /* Try few special cases based on the comparison code. */
+ /* Try a few special cases based on the comparison code. */
switch (code)
{
- case GEU:
- case GTU:
- case LEU:
- case LTU:
- case NE:
- case EQ:
- /* It is always safe to reverse EQ and NE, even for the floating
- point. Similary the unsigned comparisons are never used for
- floating point so we can reverse them in the default way. */
- return reverse_condition (code);
- case ORDERED:
- case UNORDERED:
- case LTGT:
- case UNEQ:
- /* In case we already see unordered comparison, we can be sure to
- be dealing with floating point so we don't need any more tests. */
- return reverse_condition_maybe_unordered (code);
- case UNLT:
- case UNLE:
- case UNGT:
- case UNGE:
- /* We don't have safe way to reverse these yet. */
- return UNKNOWN;
- default:
- break;
+ case GEU:
+ case GTU:
+ case LEU:
+ case LTU:
+ case NE:
+ case EQ:
+ /* It is always safe to reverse EQ and NE, even for the floating
+ point. Similarly the unsigned comparisons are never used for
+ floating point so we can reverse them in the default way. */
+ return reverse_condition (code);
+ case ORDERED:
+ case UNORDERED:
+ case LTGT:
+ case UNEQ:
+ /* In case we already see unordered comparison, we can be sure to
+ be dealing with floating point so we don't need any more tests. */
+ return reverse_condition_maybe_unordered (code);
+ case UNLT:
+ case UNLE:
+ case UNGT:
+ case UNGE:
+ /* We don't have safe way to reverse these yet. */
+ return UNKNOWN;
+ default:
+ break;
}
- /* In case we give up IEEE compatibility, all comparisons are reversible. */
- if (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
- || flag_unsafe_math_optimizations)
- return reverse_condition (code);
-
- if (GET_MODE_CLASS (mode) == MODE_CC
-#ifdef HAVE_cc0
- || arg0 == cc0_rtx
-#endif
- )
+ if (GET_MODE_CLASS (mode) == MODE_CC || CC0_P (arg0))
{
rtx prev;
/* Try to search for the comparison to determine the real mode.
mode = GET_MODE (XEXP (comparison, 1));
break;
}
- /* We can get past reg-reg moves. This may be usefull for model
+ /* We can get past reg-reg moves. This may be useful for model
of i387 comparisons that first move flag registers around. */
if (REG_P (src))
{
}
}
- /* An integer condition. */
+ /* Test for an integer condition, or a floating-point comparison
+ in which NaNs can be ignored. */
if (GET_CODE (arg0) == CONST_INT
|| (GET_MODE (arg0) != VOIDmode
&& GET_MODE_CLASS (mode) != MODE_CC
- && ! FLOAT_MODE_P (mode)))
+ && !HONOR_NANS (mode)))
return reverse_condition (code);
return UNKNOWN;
}
-/* An wrapper around the previous function to take COMPARISON as rtx
+/* A wrapper around the previous function to take COMPARISON as rtx
expression. This simplifies many callers. */
enum rtx_code
-reversed_comparison_code (comparison, insn)
- rtx comparison, insn;
+reversed_comparison_code (rtx comparison, rtx insn)
{
if (GET_RTX_CLASS (GET_CODE (comparison)) != '<')
return UNKNOWN;
Use reversed_comparison_code instead. */
enum rtx_code
-reverse_condition (code)
- enum rtx_code code;
+reverse_condition (enum rtx_code code)
{
switch (code)
{
that the target will support them too... */
enum rtx_code
-reverse_condition_maybe_unordered (code)
- enum rtx_code code;
+reverse_condition_maybe_unordered (enum rtx_code code)
{
- /* Non-IEEE formats don't have unordered conditions. */
- if (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT)
- return reverse_condition (code);
-
switch (code)
{
case EQ:
This IS safe for IEEE floating-point. */
enum rtx_code
-swap_condition (code)
- enum rtx_code code;
+swap_condition (enum rtx_code code)
{
switch (code)
{
CODE is returned. */
enum rtx_code
-unsigned_condition (code)
- enum rtx_code code;
+unsigned_condition (enum rtx_code code)
{
switch (code)
{
/* Similarly, return the signed version of a comparison. */
enum rtx_code
-signed_condition (code)
- enum rtx_code code;
+signed_condition (enum rtx_code code)
{
switch (code)
{
}
}
\f
-/* Return non-zero if CODE1 is more strict than CODE2, i.e., if the
+/* Return nonzero if CODE1 is more strict than CODE2, i.e., if the
truth of CODE1 implies the truth of CODE2. */
int
-comparison_dominates_p (code1, code2)
- enum rtx_code code1, code2;
+comparison_dominates_p (enum rtx_code code1, enum rtx_code code2)
{
/* UNKNOWN comparison codes can happen as a result of trying to revert
comparison codes.
/* Return 1 if INSN is an unconditional jump and nothing else. */
int
-simplejump_p (insn)
- rtx insn;
+simplejump_p (rtx insn)
{
return (GET_CODE (insn) == JUMP_INSN
&& GET_CODE (PATTERN (insn)) == SET
/* Return nonzero if INSN is a (possibly) conditional jump
and nothing more.
- Use this function is deprecated, since we need to support combined
+ Use of this function is deprecated, since we need to support combined
branch and compare insns. Use any_condjump_p instead whenever possible. */
int
-condjump_p (insn)
- rtx insn;
+condjump_p (rtx insn)
{
- register rtx x = PATTERN (insn);
+ rtx x = PATTERN (insn);
if (GET_CODE (x) != SET
|| GET_CODE (SET_DEST (x)) != PC)
branch and compare insns. Use any_condjump_p instead whenever possible. */
int
-condjump_in_parallel_p (insn)
- rtx insn;
+condjump_in_parallel_p (rtx insn)
{
- register rtx x = PATTERN (insn);
+ rtx x = PATTERN (insn);
if (GET_CODE (x) != PARALLEL)
return 0;
/* Return set of PC, otherwise NULL. */
rtx
-pc_set (insn)
- rtx insn;
+pc_set (rtx insn)
{
rtx pat;
if (GET_CODE (insn) != JUMP_INSN)
possibly bundled inside a PARALLEL. */
int
-any_uncondjump_p (insn)
- rtx insn;
+any_uncondjump_p (rtx insn)
{
rtx x = pc_set (insn);
if (!x)
Note that unlike condjump_p it returns false for unconditional jumps. */
int
-any_condjump_p (insn)
- rtx insn;
+any_condjump_p (rtx insn)
{
rtx x = pc_set (insn);
enum rtx_code a, b;
/* Return the label of a conditional jump. */
rtx
-condjump_label (insn)
- rtx insn;
+condjump_label (rtx insn)
{
rtx x = pc_set (insn);
/* Return true if INSN is a (possibly conditional) return insn. */
static int
-returnjump_p_1 (loc, data)
- rtx *loc;
- void *data ATTRIBUTE_UNUSED;
+returnjump_p_1 (rtx *loc, void *data ATTRIBUTE_UNUSED)
{
rtx x = *loc;
- return x && GET_CODE (x) == RETURN;
+
+ return x && (GET_CODE (x) == RETURN
+ || (GET_CODE (x) == SET && SET_IS_RETURN_P (x)));
}
int
-returnjump_p (insn)
- rtx insn;
+returnjump_p (rtx insn)
{
if (GET_CODE (insn) != JUMP_INSN)
return 0;
nothing more. */
int
-onlyjump_p (insn)
- rtx insn;
+onlyjump_p (rtx insn)
{
rtx set;
#ifdef HAVE_cc0
+/* Return nonzero if X is an RTX that only sets the condition codes
+ and has no side effects. */
+
+int
+only_sets_cc0_p (rtx x)
+{
+ if (! x)
+ return 0;
+
+ if (INSN_P (x))
+ x = PATTERN (x);
+
+ return sets_cc0_p (x) == 1 && ! side_effects_p (x);
+}
+
/* Return 1 if X is an RTX that does nothing but set the condition codes
and CLOBBER or USE registers.
Return -1 if X does explicitly set the condition codes,
but also does other things. */
int
-sets_cc0_p (x)
- rtx x ATTRIBUTE_UNUSED;
+sets_cc0_p (rtx x)
{
+ if (! x)
+ return 0;
+
+ if (INSN_P (x))
+ x = PATTERN (x);
+
if (GET_CODE (x) == SET && SET_DEST (x) == cc0_rtx)
return 1;
if (GET_CODE (x) == PARALLEL)
a USE or CLOBBER. */
rtx
-follow_jumps (label)
- rtx label;
+follow_jumps (rtx label)
{
- register rtx insn;
- register rtx next;
- register rtx value = label;
- register int depth;
+ rtx insn;
+ rtx next;
+ rtx value = label;
+ int depth;
for (depth = 0;
(depth < 10
return value;
}
-/* Assuming that field IDX of X is a vector of label_refs,
- replace each of them by the ultimate label reached by it.
- Return nonzero if a change is made.
- If IGNORE_LOOPS is 0, we do not chain across a NOTE_INSN_LOOP_BEG. */
-
-static int
-tension_vector_labels (x, idx)
- register rtx x;
- register int idx;
-{
- int changed = 0;
- register int i;
- for (i = XVECLEN (x, idx) - 1; i >= 0; i--)
- {
- register rtx olabel = XEXP (XVECEXP (x, idx, i), 0);
- register rtx nlabel = follow_jumps (olabel);
- if (nlabel && nlabel != olabel)
- {
- XEXP (XVECEXP (x, idx, i), 0) = nlabel;
- ++LABEL_NUSES (nlabel);
- if (--LABEL_NUSES (olabel) == 0)
- delete_insn (olabel);
- changed = 1;
- }
- }
- return changed;
-}
\f
/* Find all CODE_LABELs referred to in X, and increment their use counts.
If INSN is a JUMP_INSN and there is at least one CODE_LABEL referenced
must be kept distinct if we have not yet done loop-optimization,
because the gap between them is where loop-optimize
will want to move invariant code to. CROSS_JUMP tells us
- that loop-optimization is done with.
-
- Once reload has completed (CROSS_JUMP non-zero), we need not consider
- two labels distinct if they are separated by only USE or CLOBBER insns. */
+ that loop-optimization is done with. */
void
-mark_jump_label (x, insn, cross_jump, in_mem)
- register rtx x;
- rtx insn;
- int cross_jump;
- int in_mem;
+mark_jump_label (rtx x, rtx insn, int in_mem)
{
- register RTX_CODE code = GET_CODE (x);
- register int i;
- register const char *fmt;
+ RTX_CODE code = GET_CODE (x);
+ int i;
+ const char *fmt;
switch (code)
{
case PC:
case CC0:
case REG:
- case SUBREG:
case CONST_INT:
case CONST_DOUBLE:
case CLOBBER:
/* If this is a constant-pool reference, see if it is a label. */
if (CONSTANT_POOL_ADDRESS_P (x))
- mark_jump_label (get_pool_constant (x), insn, cross_jump, in_mem);
+ mark_jump_label (get_pool_constant (x), insn, in_mem);
break;
case LABEL_REF:
{
rtx label = XEXP (x, 0);
- rtx olabel = label;
- rtx next;
/* Ignore remaining references to unreachable labels that
have been deleted. */
if (LABEL_REF_NONLOCAL_P (x))
break;
- /* If there are other labels following this one,
- replace it with the last of the consecutive labels. */
- for (next = NEXT_INSN (label); next; next = NEXT_INSN (next))
- {
- if (GET_CODE (next) == CODE_LABEL)
- label = next;
- else if (cross_jump && GET_CODE (next) == INSN
- && (GET_CODE (PATTERN (next)) == USE
- || GET_CODE (PATTERN (next)) == CLOBBER))
- continue;
- else if (GET_CODE (next) != NOTE)
- break;
- else if (! cross_jump
- && (NOTE_LINE_NUMBER (next) == NOTE_INSN_LOOP_BEG
- || NOTE_LINE_NUMBER (next) == NOTE_INSN_FUNCTION_END
- /* ??? Optional. Disables some optimizations, but
- makes gcov output more accurate with -O. */
- || (flag_test_coverage
- && NOTE_LINE_NUMBER (next) > 0)))
- break;
- }
-
XEXP (x, 0) = label;
if (! insn || ! INSN_DELETED_P (insn))
++LABEL_NUSES (label);
JUMP_LABEL (insn) = label;
else
{
- /* If we've changed the label, update notes accordingly. */
- if (label != olabel)
- {
- rtx note;
-
- /* We may have a REG_LABEL note to indicate that this
- instruction uses the label. */
- note = find_reg_note (insn, REG_LABEL, olabel);
- if (note)
- XEXP (note, 0) = label;
-
- /* We may also have a REG_EQUAL note to indicate that
- a register is being set to the address of the
- label. */
- note = find_reg_note (insn, REG_EQUAL, NULL_RTX);
- if (note
- && GET_CODE (XEXP (note, 0)) == LABEL_REF
- && XEXP (XEXP (note, 0), 0) == olabel)
- XEXP (XEXP (note, 0), 0) = label;
- }
-
/* Add a REG_LABEL note for LABEL unless there already
is one. All uses of a label, except for labels
that are the targets of jumps, must have a
int eltnum = code == ADDR_DIFF_VEC ? 1 : 0;
for (i = 0; i < XVECLEN (x, eltnum); i++)
- mark_jump_label (XVECEXP (x, eltnum, i), NULL_RTX,
- cross_jump, in_mem);
+ mark_jump_label (XVECEXP (x, eltnum, i), NULL_RTX, in_mem);
}
return;
for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
{
if (fmt[i] == 'e')
- mark_jump_label (XEXP (x, i), insn, cross_jump, in_mem);
+ mark_jump_label (XEXP (x, i), insn, in_mem);
else if (fmt[i] == 'E')
{
- register int j;
+ int j;
for (j = 0; j < XVECLEN (x, i); j++)
- mark_jump_label (XVECEXP (x, i, j), insn, cross_jump, in_mem);
+ mark_jump_label (XVECEXP (x, i, j), insn, in_mem);
}
}
}
if that's what the previous thing was. */
void
-delete_jump (insn)
- rtx insn;
+delete_jump (rtx insn)
{
- register rtx set = single_set (insn);
+ rtx set = single_set (insn);
if (set && GET_CODE (SET_DEST (set)) == PC)
delete_computation (insn);
/* Verify INSN is a BARRIER and delete it. */
void
-delete_barrier (insn)
- rtx insn;
+delete_barrier (rtx insn)
{
if (GET_CODE (insn) != BARRIER)
abort ();
which is a REG_DEAD note associated with INSN. */
static void
-delete_prior_computation (note, insn)
- rtx note;
- rtx insn;
+delete_prior_computation (rtx note, rtx insn)
{
rtx our_prev;
rtx reg = XEXP (note, 0);
/* If we reach a CALL which is not calling a const function
or the callee pops the arguments, then give up. */
if (GET_CODE (our_prev) == CALL_INSN
- && (! CONST_CALL_P (our_prev)
+ && (! CONST_OR_PURE_CALL_P (our_prev)
|| GET_CODE (pat) != SET || GET_CODE (SET_SRC (pat)) != CALL))
break;
/* If we reach a SEQUENCE, it is too complex to try to
- do anything with it, so give up. */
+ do anything with it, so give up. We can be run during
+ and after reorg, so SEQUENCE rtl can legitimately show
+ up here. */
if (GET_CODE (pat) == SEQUENCE)
break;
int dest_endregno
= (dest_regno
+ (dest_regno < FIRST_PSEUDO_REGISTER
- ? HARD_REGNO_NREGS (dest_regno,
- GET_MODE (SET_DEST (pat))) : 1));
+ ? hard_regno_nregs[dest_regno]
+ [GET_MODE (SET_DEST (pat))] : 1));
int regno = REGNO (reg);
int endregno
= (regno
+ (regno < FIRST_PSEUDO_REGISTER
- ? HARD_REGNO_NREGS (regno, GET_MODE (reg)) : 1));
+ ? hard_regno_nregs[regno][GET_MODE (reg)] : 1));
if (dest_regno >= regno
&& dest_endregno <= endregno)
delete the insn that set it. */
static void
-delete_computation (insn)
- rtx insn;
+delete_computation (rtx insn)
{
rtx note, next;
delete_prior_computation (note, insn);
}
- delete_insn (insn);
+ delete_related_insns (insn);
}
\f
-/* Delete insn INSN from the chain of insns and update label ref counts.
- May delete some following insns as a consequence; may even delete
- a label elsewhere and insns that follow it.
+/* Delete insn INSN from the chain of insns and update label ref counts
+ and delete insns now unreachable.
- Returns the first insn after INSN that was not deleted. */
+ Returns the first insn after INSN that was not deleted.
+
+ Usage of this instruction is deprecated. Use delete_insn instead and
+ subsequent cfg_cleanup pass to delete unreachable code if needed. */
rtx
-delete_insn (insn)
- register rtx insn;
+delete_related_insns (rtx insn)
{
- register rtx next = NEXT_INSN (insn);
- register rtx prev = PREV_INSN (insn);
- register int was_code_label = (GET_CODE (insn) == CODE_LABEL);
- register int dont_really_delete = 0;
+ int was_code_label = (GET_CODE (insn) == CODE_LABEL);
rtx note;
+ rtx next = NEXT_INSN (insn), prev = PREV_INSN (insn);
while (next && INSN_DELETED_P (next))
next = NEXT_INSN (next);
if (INSN_DELETED_P (insn))
return next;
- if (was_code_label)
- remove_node_from_expr_list (insn, &nonlocal_goto_handler_labels);
-
- /* Don't delete user-declared labels. When optimizing, convert them
- to special NOTEs instead. When not optimizing, leave them alone. */
- if (was_code_label && LABEL_NAME (insn) != 0)
- {
- if (optimize)
- {
- const char *name = LABEL_NAME (insn);
- PUT_CODE (insn, NOTE);
- NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED_LABEL;
- NOTE_SOURCE_FILE (insn) = name;
- }
-
- dont_really_delete = 1;
- }
- else
- /* Mark this insn as deleted. */
- INSN_DELETED_P (insn) = 1;
-
- /* If this is an unconditional jump, delete it from the jump chain. */
- if (simplejump_p (insn))
- delete_from_jump_chain (insn);
+ delete_insn (insn);
/* If instruction is followed by a barrier,
delete the barrier too. */
if (next != 0 && GET_CODE (next) == BARRIER)
- {
- INSN_DELETED_P (next) = 1;
- next = NEXT_INSN (next);
- }
-
- /* Patch out INSN (and the barrier if any) */
-
- if (! dont_really_delete)
- {
- if (prev)
- {
- NEXT_INSN (prev) = next;
- if (GET_CODE (prev) == INSN && GET_CODE (PATTERN (prev)) == SEQUENCE)
- NEXT_INSN (XVECEXP (PATTERN (prev), 0,
- XVECLEN (PATTERN (prev), 0) - 1)) = next;
- }
-
- if (next)
- {
- PREV_INSN (next) = prev;
- if (GET_CODE (next) == INSN && GET_CODE (PATTERN (next)) == SEQUENCE)
- PREV_INSN (XVECEXP (PATTERN (next), 0, 0)) = prev;
- }
-
- if (prev && NEXT_INSN (prev) == 0)
- set_last_insn (prev);
- }
+ delete_insn (next);
/* If deleting a jump, decrement the count of the label,
and delete the label if it is now unused. */
{
rtx lab = JUMP_LABEL (insn), lab_next;
- if (--LABEL_NUSES (lab) == 0)
+ if (LABEL_NUSES (lab) == 0)
{
/* This can delete NEXT or PREV,
either directly if NEXT is JUMP_LABEL (INSN),
or indirectly through more levels of jumps. */
- delete_insn (lab);
+ delete_related_insns (lab);
/* I feel a little doubtful about this loop,
but I see no clean and sure alternative way
next = NEXT_INSN (next);
return next;
}
- else if ((lab_next = next_nonnote_insn (lab)) != NULL
- && GET_CODE (lab_next) == JUMP_INSN
- && (GET_CODE (PATTERN (lab_next)) == ADDR_VEC
- || GET_CODE (PATTERN (lab_next)) == ADDR_DIFF_VEC))
+ else if (tablejump_p (insn, NULL, &lab_next))
{
/* If we're deleting the tablejump, delete the dispatch table.
- We may not be able to kill the label immediately preceeding
+ We may not be able to kill the label immediately preceding
just yet, as it might be referenced in code leading up to
the tablejump. */
- delete_insn (lab_next);
+ delete_related_insns (lab_next);
}
}
int len = XVECLEN (pat, diff_vec_p);
for (i = 0; i < len; i++)
- if (--LABEL_NUSES (XEXP (XVECEXP (pat, diff_vec_p, i), 0)) == 0)
- delete_insn (XEXP (XVECEXP (pat, diff_vec_p, i), 0));
+ if (LABEL_NUSES (XEXP (XVECEXP (pat, diff_vec_p, i), 0)) == 0)
+ delete_related_insns (XEXP (XVECEXP (pat, diff_vec_p, i), 0));
while (next && INSN_DELETED_P (next))
next = NEXT_INSN (next);
return next;
if (REG_NOTE_KIND (note) == REG_LABEL
/* This could also be a NOTE_INSN_DELETED_LABEL note. */
&& GET_CODE (XEXP (note, 0)) == CODE_LABEL)
- if (--LABEL_NUSES (XEXP (note, 0)) == 0)
- delete_insn (XEXP (note, 0));
+ if (LABEL_NUSES (XEXP (note, 0)) == 0)
+ delete_related_insns (XEXP (note, 0));
while (prev && (INSN_DELETED_P (prev) || GET_CODE (prev) == NOTE))
prev = PREV_INSN (prev);
&& GET_CODE (NEXT_INSN (insn)) == JUMP_INSN
&& (GET_CODE (PATTERN (NEXT_INSN (insn))) == ADDR_VEC
|| GET_CODE (PATTERN (NEXT_INSN (insn))) == ADDR_DIFF_VEC))
- next = delete_insn (NEXT_INSN (insn));
+ next = delete_related_insns (NEXT_INSN (insn));
/* If INSN was a label, delete insns following it if now unreachable. */
if (was_code_label && prev && GET_CODE (prev) == BARRIER)
{
- register RTX_CODE code;
+ RTX_CODE code;
while (next != 0
&& (GET_RTX_CLASS (code = GET_CODE (next)) == 'i'
|| code == NOTE || code == BARRIER
deletion of unreachable code, after a different label.
As long as the value from this recursive call is correct,
this invocation functions correctly. */
- next = delete_insn (next);
+ next = delete_related_insns (next);
}
}
return next;
}
-
-/* Advance from INSN till reaching something not deleted
- then return that. May return INSN itself. */
-
-rtx
-next_nondeleted_insn (insn)
- rtx insn;
-{
- while (INSN_DELETED_P (insn))
- insn = NEXT_INSN (insn);
- return insn;
-}
\f
/* Delete a range of insns from FROM to TO, inclusive.
This is for the sake of peephole optimization, so assume
peephole insn that will replace them. */
void
-delete_for_peephole (from, to)
- register rtx from, to;
+delete_for_peephole (rtx from, rtx to)
{
- register rtx insn = from;
+ rtx insn = from;
while (1)
{
- register rtx next = NEXT_INSN (insn);
- register rtx prev = PREV_INSN (insn);
+ rtx next = NEXT_INSN (insn);
+ rtx prev = PREV_INSN (insn);
if (GET_CODE (insn) != NOTE)
{
is also an unconditional jump in that case. */
}
\f
-/* We have determined that INSN is never reached, and are about to
- delete it. Print a warning if the user asked for one.
+/* We have determined that AVOIDED_INSN is never reached, and are
+ about to delete it. If the insn chain between AVOIDED_INSN and
+ FINISH contains more than one line from the current function, and
+ contains at least one operation, print a warning if the user asked
+ for it. If FINISH is NULL, look between AVOIDED_INSN and a LABEL.
- To try to make this warning more useful, this should only be called
- once per basic block not reached, and it only warns when the basic
- block contains more than one line from the current function, and
- contains at least one operation. CSE and inlining can duplicate insns,
- so it's possible to get spurious warnings from this. */
+ CSE and inlining can duplicate insns, so it's possible to get
+ spurious warnings from this. */
void
-never_reached_warning (avoided_insn)
- rtx avoided_insn;
+never_reached_warning (rtx avoided_insn, rtx finish)
{
rtx insn;
rtx a_line_note = NULL;
- int two_avoided_lines = 0;
- int contains_insn = 0;
+ int two_avoided_lines = 0, contains_insn = 0, reached_end = 0;
- if (! warn_notreached)
+ if (!warn_notreached)
return;
- /* Scan forwards, looking at LINE_NUMBER notes, until
- we hit a LABEL or we run out of insns. */
+ /* Back up to the first of any NOTEs preceding avoided_insn; flow passes
+ us the head of a block, a NOTE_INSN_BASIC_BLOCK, which often follows
+ the line note. */
+ insn = avoided_insn;
+ while (1)
+ {
+ rtx prev = PREV_INSN (insn);
+ if (prev == NULL_RTX
+ || GET_CODE (prev) != NOTE)
+ break;
+ insn = prev;
+ }
+
+ /* Scan forwards, looking at LINE_NUMBER notes, until we hit a LABEL
+ in case FINISH is NULL, otherwise until we run out of insns. */
- for (insn = avoided_insn; insn != NULL; insn = NEXT_INSN (insn))
+ for (; insn != NULL; insn = NEXT_INSN (insn))
{
- if (GET_CODE (insn) == CODE_LABEL)
+ if ((finish == NULL && GET_CODE (insn) == CODE_LABEL)
+ || GET_CODE (insn) == BARRIER)
break;
- else if (GET_CODE (insn) == NOTE /* A line number note? */
- && NOTE_LINE_NUMBER (insn) >= 0)
+
+ if (GET_CODE (insn) == NOTE /* A line number note? */
+ && NOTE_LINE_NUMBER (insn) >= 0)
{
if (a_line_note == NULL)
a_line_note = insn;
!= NOTE_LINE_NUMBER (insn));
}
else if (INSN_P (insn))
- contains_insn = 1;
+ {
+ if (reached_end)
+ break;
+ contains_insn = 1;
+ }
+
+ if (insn == finish)
+ reached_end = 1;
}
if (two_avoided_lines && contains_insn)
- warning_with_file_and_line (NOTE_SOURCE_FILE (a_line_note),
- NOTE_LINE_NUMBER (a_line_note),
- "will never be executed");
+ {
+ location_t locus;
+ locus.file = NOTE_SOURCE_FILE (a_line_note);
+ locus.line = NOTE_LINE_NUMBER (a_line_note);
+ warning ("%Hwill never be executed", &locus);
+ }
}
\f
/* Throughout LOC, redirect OLABEL to NLABEL. Treat null OLABEL or
NLABEL as a return. Accrue modifications into the change group. */
static void
-redirect_exp_1 (loc, olabel, nlabel, insn)
- rtx *loc;
- rtx olabel, nlabel;
- rtx insn;
+redirect_exp_1 (rtx *loc, rtx olabel, rtx nlabel, rtx insn)
{
- register rtx x = *loc;
- register RTX_CODE code = GET_CODE (x);
- register int i;
- register const char *fmt;
+ rtx x = *loc;
+ RTX_CODE code = GET_CODE (x);
+ int i;
+ const char *fmt;
if (code == LABEL_REF)
{
redirect_exp_1 (&XEXP (x, i), olabel, nlabel, insn);
else if (fmt[i] == 'E')
{
- register int j;
+ int j;
for (j = 0; j < XVECLEN (x, i); j++)
redirect_exp_1 (&XVECEXP (x, i, j), olabel, nlabel, insn);
}
/* Similar, but apply the change group and report success or failure. */
static int
-redirect_exp (olabel, nlabel, insn)
- rtx olabel, nlabel;
- rtx insn;
+redirect_exp (rtx olabel, rtx nlabel, rtx insn)
{
rtx *loc;
not see how to do that. */
int
-redirect_jump_1 (jump, nlabel)
- rtx jump, nlabel;
+redirect_jump_1 (rtx jump, rtx nlabel)
{
int ochanges = num_validated_changes ();
rtx *loc;
(this can only occur for NLABEL == 0). */
int
-redirect_jump (jump, nlabel, delete_unused)
- rtx jump, nlabel;
- int delete_unused;
+redirect_jump (rtx jump, rtx nlabel, int delete_unused)
{
- register rtx olabel = JUMP_LABEL (jump);
+ rtx olabel = JUMP_LABEL (jump);
+ rtx note;
if (nlabel == olabel)
return 1;
if (! redirect_exp (olabel, nlabel, jump))
return 0;
- /* If this is an unconditional branch, delete it from the jump_chain of
- OLABEL and add it to the jump_chain of NLABEL (assuming both labels
- have UID's in range and JUMP_CHAIN is valid). */
- if (jump_chain && (simplejump_p (jump)
- || GET_CODE (PATTERN (jump)) == RETURN))
+ JUMP_LABEL (jump) = nlabel;
+ if (nlabel)
+ ++LABEL_NUSES (nlabel);
+
+ /* Update labels in any REG_EQUAL note. */
+ if ((note = find_reg_note (jump, REG_EQUAL, NULL_RTX)) != NULL_RTX)
{
- int label_index = nlabel ? INSN_UID (nlabel) : 0;
-
- delete_from_jump_chain (jump);
- if (label_index < max_jump_chain
- && INSN_UID (jump) < max_jump_chain)
+ if (nlabel && olabel)
{
- jump_chain[INSN_UID (jump)] = jump_chain[label_index];
- jump_chain[label_index] = jump;
+ rtx dest = XEXP (note, 0);
+
+ if (GET_CODE (dest) == IF_THEN_ELSE)
+ {
+ if (GET_CODE (XEXP (dest, 1)) == LABEL_REF
+ && XEXP (XEXP (dest, 1), 0) == olabel)
+ XEXP (XEXP (dest, 1), 0) = nlabel;
+ if (GET_CODE (XEXP (dest, 2)) == LABEL_REF
+ && XEXP (XEXP (dest, 2), 0) == olabel)
+ XEXP (XEXP (dest, 2), 0) = nlabel;
+ }
+ else
+ remove_note (jump, note);
}
+ else
+ remove_note (jump, note);
}
- JUMP_LABEL (jump) = nlabel;
- if (nlabel)
- ++LABEL_NUSES (nlabel);
-
/* If we're eliding the jump over exception cleanups at the end of a
function, move the function end note so that -Wreturn-type works. */
if (olabel && nlabel
&& NOTE_LINE_NUMBER (NEXT_INSN (olabel)) == NOTE_INSN_FUNCTION_END)
emit_note_after (NOTE_INSN_FUNCTION_END, nlabel);
- if (olabel && --LABEL_NUSES (olabel) == 0 && delete_unused)
- delete_insn (olabel);
+ if (olabel && --LABEL_NUSES (olabel) == 0 && delete_unused
+ /* Undefined labels will remain outside the insn stream. */
+ && INSN_UID (olabel))
+ delete_related_insns (olabel);
return 1;
}
Accrue the modifications into the change group. */
static void
-invert_exp_1 (insn)
- rtx insn;
+invert_exp_1 (rtx insn)
{
- register RTX_CODE code;
+ RTX_CODE code;
rtx x = pc_set (insn);
if (!x)
if (code == IF_THEN_ELSE)
{
- register rtx comp = XEXP (x, 0);
- register rtx tem;
+ rtx comp = XEXP (x, 0);
+ rtx tem;
enum rtx_code reversed_code;
/* We can do this in two ways: The preferable way, which can only
matches a pattern. */
static int
-invert_exp (insn)
- rtx insn;
+invert_exp (rtx insn)
{
invert_exp_1 (insn);
if (num_validated_changes () == 0)
inversion and redirection. */
int
-invert_jump_1 (jump, nlabel)
- rtx jump, nlabel;
+invert_jump_1 (rtx jump, rtx nlabel)
{
int ochanges;
NLABEL instead of where it jumps now. Return true if successful. */
int
-invert_jump (jump, nlabel, delete_unused)
- rtx jump, nlabel;
- int delete_unused;
+invert_jump (rtx jump, rtx nlabel, int delete_unused)
{
/* We have to either invert the condition and change the label or
do neither. Either operation could fail. We first try to invert
if (redirect_jump (jump, nlabel, delete_unused))
{
+ /* Remove REG_EQUAL note if we have one. */
+ rtx note = find_reg_note (jump, REG_EQUAL, NULL_RTX);
+ if (note)
+ remove_note (jump, note);
+
invert_br_probabilities (jump);
return 1;
return 0;
}
-/* Delete the instruction JUMP from any jump chain it might be on. */
-
-static void
-delete_from_jump_chain (jump)
- rtx jump;
-{
- int index;
- rtx olabel = JUMP_LABEL (jump);
-
- /* Handle unconditional jumps. */
- if (jump_chain && olabel != 0
- && INSN_UID (olabel) < max_jump_chain
- && simplejump_p (jump))
- index = INSN_UID (olabel);
- /* Handle return insns. */
- else if (jump_chain && GET_CODE (PATTERN (jump)) == RETURN)
- index = 0;
- else
- return;
-
- if (jump_chain[index] == jump)
- jump_chain[index] = jump_chain[INSN_UID (jump)];
- else
- {
- rtx insn;
-
- for (insn = jump_chain[index];
- insn != 0;
- insn = jump_chain[INSN_UID (insn)])
- if (jump_chain[INSN_UID (insn)] == jump)
- {
- jump_chain[INSN_UID (insn)] = jump_chain[INSN_UID (jump)];
- break;
- }
- }
-}
-\f
-/* Make jump JUMP jump to label NLABEL, assuming it used to be a tablejump.
-
- If the old jump target label (before the dispatch table) becomes unused,
- it and the dispatch table may be deleted. In that case, find the insn
- before the jump references that label and delete it and logical successors
- too. */
-
-static void
-redirect_tablejump (jump, nlabel)
- rtx jump, nlabel;
-{
- register rtx olabel = JUMP_LABEL (jump);
- rtx *notep, note, next;
-
- /* Add this jump to the jump_chain of NLABEL. */
- if (jump_chain && INSN_UID (nlabel) < max_jump_chain
- && INSN_UID (jump) < max_jump_chain)
- {
- jump_chain[INSN_UID (jump)] = jump_chain[INSN_UID (nlabel)];
- jump_chain[INSN_UID (nlabel)] = jump;
- }
-
- for (notep = ®_NOTES (jump), note = *notep; note; note = next)
- {
- next = XEXP (note, 1);
-
- if (REG_NOTE_KIND (note) != REG_DEAD
- /* Verify that the REG_NOTE is legitimate. */
- || GET_CODE (XEXP (note, 0)) != REG
- || ! reg_mentioned_p (XEXP (note, 0), PATTERN (jump)))
- notep = &XEXP (note, 1);
- else
- {
- delete_prior_computation (note, jump);
- *notep = next;
- }
- }
-
- PATTERN (jump) = gen_jump (nlabel);
- JUMP_LABEL (jump) = nlabel;
- ++LABEL_NUSES (nlabel);
- INSN_CODE (jump) = -1;
-
- if (--LABEL_NUSES (olabel) == 0)
- {
- delete_labelref_insn (jump, olabel, 0);
- delete_insn (olabel);
- }
-}
-
-/* Find the insn referencing LABEL that is a logical predecessor of INSN.
- If we found one, delete it and then delete this insn if DELETE_THIS is
- non-zero. Return non-zero if INSN or a predecessor references LABEL. */
-
-static int
-delete_labelref_insn (insn, label, delete_this)
- rtx insn, label;
- int delete_this;
-{
- int deleted = 0;
- rtx link;
-
- if (GET_CODE (insn) != NOTE
- && reg_mentioned_p (label, PATTERN (insn)))
- {
- if (delete_this)
- {
- delete_insn (insn);
- deleted = 1;
- }
- else
- return 1;
- }
-
- for (link = LOG_LINKS (insn); link; link = XEXP (link, 1))
- if (delete_labelref_insn (XEXP (link, 0), label, 1))
- {
- if (delete_this)
- {
- delete_insn (insn);
- deleted = 1;
- }
- else
- return 1;
- }
-
- return deleted;
-}
\f
/* Like rtx_equal_p except that it considers two REGs as equal
if they renumber to the same value and considers two commutative
case when the PLUS is inside a MEM. */
int
-rtx_renumbered_equal_p (x, y)
- rtx x, y;
+rtx_renumbered_equal_p (rtx x, rtx y)
{
- register int i;
- register RTX_CODE code = GET_CODE (x);
- register const char *fmt;
+ int i;
+ RTX_CODE code = GET_CODE (x);
+ const char *fmt;
if (x == y)
return 1;
case CC0:
case ADDR_VEC:
case ADDR_DIFF_VEC:
- return 0;
-
case CONST_INT:
- return INTVAL (x) == INTVAL (y);
+ return 0;
case LABEL_REF:
/* We can't assume nonlocal labels have their following insns yet. */
fmt = GET_RTX_FORMAT (code);
for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
{
- register int j;
+ int j;
switch (fmt[i])
{
case 'w':
case 'u':
if (XEXP (x, i) != XEXP (y, i))
return 0;
- /* fall through. */
+ /* Fall through. */
case '0':
break;
return -1. Any rtx is valid for X. */
int
-true_regnum (x)
- rtx x;
+true_regnum (rtx x)
{
if (GET_CODE (x) == REG)
{
}
return -1;
}
-\f
-/* Optimize code of the form:
-
- for (x = a[i]; x; ...)
- ...
- for (x = a[i]; x; ...)
- ...
- foo:
-
- Loop optimize will change the above code into
-
- if (x = a[i])
- for (;;)
- { ...; if (! (x = ...)) break; }
- if (x = a[i])
- for (;;)
- { ...; if (! (x = ...)) break; }
- foo:
-
- In general, if the first test fails, the program can branch
- directly to `foo' and skip the second try which is doomed to fail.
- We run this after loop optimization and before flow analysis. */
-
-/* When comparing the insn patterns, we track the fact that different
- pseudo-register numbers may have been used in each computation.
- The following array stores an equivalence -- same_regs[I] == J means
- that pseudo register I was used in the first set of tests in a context
- where J was used in the second set. We also count the number of such
- pending equivalences. If nonzero, the expressions really aren't the
- same. */
-
-static int *same_regs;
-
-static int num_same_regs;
-
-/* Track any registers modified between the target of the first jump and
- the second jump. They never compare equal. */
-
-static char *modified_regs;
-
-/* Record if memory was modified. */
-
-static int modified_mem;
-
-/* Called via note_stores on each insn between the target of the first
- branch and the second branch. It marks any changed registers. */
-
-static void
-mark_modified_reg (dest, x, data)
- rtx dest;
- rtx x;
- void *data ATTRIBUTE_UNUSED;
-{
- int regno;
- unsigned int i;
-
- if (GET_CODE (dest) == SUBREG)
- dest = SUBREG_REG (dest);
-
- if (GET_CODE (dest) == MEM)
- modified_mem = 1;
-
- if (GET_CODE (dest) != REG)
- return;
-
- regno = REGNO (dest);
- if (regno >= FIRST_PSEUDO_REGISTER)
- modified_regs[regno] = 1;
- /* Don't consider a hard condition code register as modified,
- if it is only being set. thread_jumps will check if it is set
- to the same value. */
- else if (GET_MODE_CLASS (GET_MODE (dest)) != MODE_CC
- || GET_CODE (x) != SET
- || ! rtx_equal_p (dest, SET_DEST (x))
- || HARD_REGNO_NREGS (regno, GET_MODE (dest)) != 1)
- for (i = 0; i < HARD_REGNO_NREGS (regno, GET_MODE (dest)); i++)
- modified_regs[regno + i] = 1;
-}
-
-/* F is the first insn in the chain of insns. */
-
-void
-thread_jumps (f, max_reg, flag_before_loop)
- rtx f;
- int max_reg;
- int flag_before_loop;
-{
- /* Basic algorithm is to find a conditional branch,
- the label it may branch to, and the branch after
- that label. If the two branches test the same condition,
- walk back from both branch paths until the insn patterns
- differ, or code labels are hit. If we make it back to
- the target of the first branch, then we know that the first branch
- will either always succeed or always fail depending on the relative
- senses of the two branches. So adjust the first branch accordingly
- in this case. */
-
- rtx label, b1, b2, t1, t2;
- enum rtx_code code1, code2;
- rtx b1op0, b1op1, b2op0, b2op1;
- int changed = 1;
- int i;
- int *all_reset;
- enum rtx_code reversed_code1, reversed_code2;
-
- /* Allocate register tables and quick-reset table. */
- modified_regs = (char *) xmalloc (max_reg * sizeof (char));
- same_regs = (int *) xmalloc (max_reg * sizeof (int));
- all_reset = (int *) xmalloc (max_reg * sizeof (int));
- for (i = 0; i < max_reg; i++)
- all_reset[i] = -1;
-
- while (changed)
- {
- changed = 0;
-
- for (b1 = f; b1; b1 = NEXT_INSN (b1))
- {
- rtx set;
- rtx set2;
-
- /* Get to a candidate branch insn. */
- if (GET_CODE (b1) != JUMP_INSN
- || ! any_condjump_p (b1) || JUMP_LABEL (b1) == 0)
- continue;
-
- memset (modified_regs, 0, max_reg * sizeof (char));
- modified_mem = 0;
-
- memcpy (same_regs, all_reset, max_reg * sizeof (int));
- num_same_regs = 0;
-
- label = JUMP_LABEL (b1);
-
- /* Look for a branch after the target. Record any registers and
- memory modified between the target and the branch. Stop when we
- get to a label since we can't know what was changed there. */
- for (b2 = NEXT_INSN (label); b2; b2 = NEXT_INSN (b2))
- {
- if (GET_CODE (b2) == CODE_LABEL)
- break;
-
- else if (GET_CODE (b2) == JUMP_INSN)
- {
- /* If this is an unconditional jump and is the only use of
- its target label, we can follow it. */
- if (any_uncondjump_p (b2)
- && onlyjump_p (b2)
- && JUMP_LABEL (b2) != 0
- && LABEL_NUSES (JUMP_LABEL (b2)) == 1)
- {
- b2 = JUMP_LABEL (b2);
- continue;
- }
- else
- break;
- }
-
- if (GET_CODE (b2) != CALL_INSN && GET_CODE (b2) != INSN)
- continue;
-
- if (GET_CODE (b2) == CALL_INSN)
- {
- modified_mem = 1;
- for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
- if (call_used_regs[i] && ! fixed_regs[i]
- && i != STACK_POINTER_REGNUM
- && i != FRAME_POINTER_REGNUM
- && i != HARD_FRAME_POINTER_REGNUM
- && i != ARG_POINTER_REGNUM)
- modified_regs[i] = 1;
- }
-
- note_stores (PATTERN (b2), mark_modified_reg, NULL);
- }
-
- /* Check the next candidate branch insn from the label
- of the first. */
- if (b2 == 0
- || GET_CODE (b2) != JUMP_INSN
- || b2 == b1
- || !any_condjump_p (b2)
- || !onlyjump_p (b2))
- continue;
- set = pc_set (b1);
- set2 = pc_set (b2);
-
- /* Get the comparison codes and operands, reversing the
- codes if appropriate. If we don't have comparison codes,
- we can't do anything. */
- b1op0 = XEXP (XEXP (SET_SRC (set), 0), 0);
- b1op1 = XEXP (XEXP (SET_SRC (set), 0), 1);
- code1 = GET_CODE (XEXP (SET_SRC (set), 0));
- reversed_code1 = code1;
- if (XEXP (SET_SRC (set), 1) == pc_rtx)
- code1 = reversed_comparison_code (XEXP (SET_SRC (set), 0), b1);
- else
- reversed_code1 = reversed_comparison_code (XEXP (SET_SRC (set), 0), b1);
-
- b2op0 = XEXP (XEXP (SET_SRC (set2), 0), 0);
- b2op1 = XEXP (XEXP (SET_SRC (set2), 0), 1);
- code2 = GET_CODE (XEXP (SET_SRC (set2), 0));
- reversed_code2 = code2;
- if (XEXP (SET_SRC (set2), 1) == pc_rtx)
- code2 = reversed_comparison_code (XEXP (SET_SRC (set2), 0), b2);
- else
- reversed_code2 = reversed_comparison_code (XEXP (SET_SRC (set2), 0), b2);
-
- /* If they test the same things and knowing that B1 branches
- tells us whether or not B2 branches, check if we
- can thread the branch. */
- if (rtx_equal_for_thread_p (b1op0, b2op0, b2)
- && rtx_equal_for_thread_p (b1op1, b2op1, b2)
- && (comparison_dominates_p (code1, code2)
- || comparison_dominates_p (code1, reversed_code2)))
-
- {
- t1 = prev_nonnote_insn (b1);
- t2 = prev_nonnote_insn (b2);
-
- while (t1 != 0 && t2 != 0)
- {
- if (t2 == label)
- {
- /* We have reached the target of the first branch.
- If there are no pending register equivalents,
- we know that this branch will either always
- succeed (if the senses of the two branches are
- the same) or always fail (if not). */
- rtx new_label;
-
- if (num_same_regs != 0)
- break;
-
- if (comparison_dominates_p (code1, code2))
- new_label = JUMP_LABEL (b2);
- else
- new_label = get_label_after (b2);
-
- if (JUMP_LABEL (b1) != new_label)
- {
- rtx prev = PREV_INSN (new_label);
-
- if (flag_before_loop
- && GET_CODE (prev) == NOTE
- && NOTE_LINE_NUMBER (prev) == NOTE_INSN_LOOP_BEG)
- {
- /* Don't thread to the loop label. If a loop
- label is reused, loop optimization will
- be disabled for that loop. */
- new_label = gen_label_rtx ();
- emit_label_after (new_label, PREV_INSN (prev));
- }
- changed |= redirect_jump (b1, new_label, 1);
- }
- break;
- }
-
- /* If either of these is not a normal insn (it might be
- a JUMP_INSN, CALL_INSN, or CODE_LABEL) we fail. (NOTEs
- have already been skipped above.) Similarly, fail
- if the insns are different. */
- if (GET_CODE (t1) != INSN || GET_CODE (t2) != INSN
- || recog_memoized (t1) != recog_memoized (t2)
- || ! rtx_equal_for_thread_p (PATTERN (t1),
- PATTERN (t2), t2))
- break;
-
- t1 = prev_nonnote_insn (t1);
- t2 = prev_nonnote_insn (t2);
- }
- }
- }
- }
-
- /* Clean up. */
- free (modified_regs);
- free (same_regs);
- free (all_reset);
-}
-\f
-/* This is like RTX_EQUAL_P except that it knows about our handling of
- possibly equivalent registers and knows to consider volatile and
- modified objects as not equal.
- YINSN is the insn containing Y. */
-
-int
-rtx_equal_for_thread_p (x, y, yinsn)
- rtx x, y;
- rtx yinsn;
+/* Return regno of the register REG and handle subregs too. */
+unsigned int
+reg_or_subregno (rtx reg)
{
- register int i;
- register int j;
- register enum rtx_code code;
- register const char *fmt;
-
- code = GET_CODE (x);
- /* Rtx's of different codes cannot be equal. */
- if (code != GET_CODE (y))
- return 0;
-
- /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent.
- (REG:SI x) and (REG:HI x) are NOT equivalent. */
-
- if (GET_MODE (x) != GET_MODE (y))
- return 0;
-
- /* For floating-point, consider everything unequal. This is a bit
- pessimistic, but this pass would only rarely do anything for FP
- anyway. */
- if (TARGET_FLOAT_FORMAT == IEEE_FLOAT_FORMAT
- && FLOAT_MODE_P (GET_MODE (x)) && ! flag_unsafe_math_optimizations)
- return 0;
-
- /* For commutative operations, the RTX match if the operand match in any
- order. Also handle the simple binary and unary cases without a loop. */
- if (code == EQ || code == NE || GET_RTX_CLASS (code) == 'c')
- return ((rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn)
- && rtx_equal_for_thread_p (XEXP (x, 1), XEXP (y, 1), yinsn))
- || (rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 1), yinsn)
- && rtx_equal_for_thread_p (XEXP (x, 1), XEXP (y, 0), yinsn)));
- else if (GET_RTX_CLASS (code) == '<' || GET_RTX_CLASS (code) == '2')
- return (rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn)
- && rtx_equal_for_thread_p (XEXP (x, 1), XEXP (y, 1), yinsn));
- else if (GET_RTX_CLASS (code) == '1')
- return rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn);
-
- /* Handle special-cases first. */
- switch (code)
- {
- case REG:
- if (REGNO (x) == REGNO (y) && ! modified_regs[REGNO (x)])
- return 1;
-
- /* If neither is user variable or hard register, check for possible
- equivalence. */
- if (REG_USERVAR_P (x) || REG_USERVAR_P (y)
- || REGNO (x) < FIRST_PSEUDO_REGISTER
- || REGNO (y) < FIRST_PSEUDO_REGISTER)
- return 0;
-
- if (same_regs[REGNO (x)] == -1)
- {
- same_regs[REGNO (x)] = REGNO (y);
- num_same_regs++;
-
- /* If this is the first time we are seeing a register on the `Y'
- side, see if it is the last use. If not, we can't thread the
- jump, so mark it as not equivalent. */
- if (REGNO_LAST_UID (REGNO (y)) != INSN_UID (yinsn))
- return 0;
-
- return 1;
- }
- else
- return (same_regs[REGNO (x)] == (int) REGNO (y));
-
- break;
-
- case MEM:
- /* If memory modified or either volatile, not equivalent.
- Else, check address. */
- if (modified_mem || MEM_VOLATILE_P (x) || MEM_VOLATILE_P (y))
- return 0;
-
- return rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn);
-
- case ASM_INPUT:
- if (MEM_VOLATILE_P (x) || MEM_VOLATILE_P (y))
- return 0;
-
- break;
-
- case SET:
- /* Cancel a pending `same_regs' if setting equivalenced registers.
- Then process source. */
- if (GET_CODE (SET_DEST (x)) == REG
- && GET_CODE (SET_DEST (y)) == REG)
- {
- if (same_regs[REGNO (SET_DEST (x))] == (int) REGNO (SET_DEST (y)))
- {
- same_regs[REGNO (SET_DEST (x))] = -1;
- num_same_regs--;
- }
- else if (REGNO (SET_DEST (x)) != REGNO (SET_DEST (y)))
- return 0;
- }
- else
- {
- if (rtx_equal_for_thread_p (SET_DEST (x), SET_DEST (y), yinsn) == 0)
- return 0;
- }
-
- return rtx_equal_for_thread_p (SET_SRC (x), SET_SRC (y), yinsn);
-
- case LABEL_REF:
- return XEXP (x, 0) == XEXP (y, 0);
-
- case SYMBOL_REF:
- return XSTR (x, 0) == XSTR (y, 0);
-
- default:
- break;
- }
-
- if (x == y)
- return 1;
-
- fmt = GET_RTX_FORMAT (code);
- for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
- {
- switch (fmt[i])
- {
- case 'w':
- if (XWINT (x, i) != XWINT (y, i))
- return 0;
- break;
-
- case 'n':
- case 'i':
- if (XINT (x, i) != XINT (y, i))
- return 0;
- break;
-
- case 'V':
- case 'E':
- /* Two vectors must have the same length. */
- if (XVECLEN (x, i) != XVECLEN (y, i))
- return 0;
-
- /* And the corresponding elements must match. */
- for (j = 0; j < XVECLEN (x, i); j++)
- if (rtx_equal_for_thread_p (XVECEXP (x, i, j),
- XVECEXP (y, i, j), yinsn) == 0)
- return 0;
- break;
-
- case 'e':
- if (rtx_equal_for_thread_p (XEXP (x, i), XEXP (y, i), yinsn) == 0)
- return 0;
- break;
-
- case 'S':
- case 's':
- if (strcmp (XSTR (x, i), XSTR (y, i)))
- return 0;
- break;
-
- case 'u':
- /* These are just backpointers, so they don't matter. */
- break;
-
- case '0':
- case 't':
- break;
-
- /* It is believed that rtx's at this level will never
- contain anything but integers and other rtx's,
- except for within LABEL_REFs and SYMBOL_REFs. */
- default:
- abort ();
- }
- }
- return 1;
+ if (REG_P (reg))
+ return REGNO (reg);
+ if (GET_CODE (reg) == SUBREG)
+ return REGNO (SUBREG_REG (reg));
+ abort ();
}
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