Skip to content

R
riscv-gcc-1
Commit 269ef46c by David S. Miller Committed by David S. Miller
Options

Begin cleaning up jump.c 

	Begin cleaning up jump.c
	* jump.c (init_label_info, delete_barrier_successors,
	mark_all_labels, delete_unreferenced_labels,
	delete_noop_moves, calculate_can_reach_end): New functions broken
	out of jump_optimize.
	(jump_optimize): Use them.

From-SVN: r23539
parent b37f006b
Showing with 521 additions and 443 deletions
gcc/ChangeLog
Thu Nov 5 07:59:05 1998 David S. Miller <davem@pierdol.cobaltmicro.com>
* jump.c (init_label_info, delete_barrier_successors,
mark_all_labels, delete_unreferenced_labels,
delete_noop_moves, calculate_can_reach_end): New functions broken
out of jump_optimize.
(jump_optimize): Use them.
Thu Nov 5 07:57:45 EST 1998 Andrew MacLeod <amacleod@cygnus.com> Thu Nov 5 07:57:45 EST 1998 Andrew MacLeod <amacleod@cygnus.com>
* except.c (expand_fixup_region_end): Make sure outer context labels * except.c (expand_fixup_region_end): Make sure outer context labels
......
gcc/jump.c
...@@ -108,6 +108,12 @@ int can_reach_end; ...@@ -108,6 +108,12 @@ int can_reach_end;
static int cross_jump_death_matters = 0; static int cross_jump_death_matters = 0;
static int init_label_info PROTO((rtx));
static void delete_barrier_successors PROTO((rtx));
static void mark_all_labels PROTO((rtx, int));
static rtx delete_unreferenced_labels PROTO((rtx));
static void delete_noop_moves PROTO((rtx));
static int calculate_can_reach_end PROTO((rtx, int, int));
static int duplicate_loop_exit_test PROTO((rtx)); static int duplicate_loop_exit_test PROTO((rtx));
static void find_cross_jump PROTO((rtx, rtx, int, rtx *, rtx *)); static void find_cross_jump PROTO((rtx, rtx, int, rtx *, rtx *));
static void do_cross_jump PROTO((rtx, rtx, rtx)); static void do_cross_jump PROTO((rtx, rtx, rtx));
...@@ -157,30 +163,7 @@ jump_optimize (f, cross_jump, noop_moves, after_regscan) ...@@ -157,30 +163,7 @@ jump_optimize (f, cross_jump, noop_moves, after_regscan)
rtx last_insn; rtx last_insn;
cross_jump_death_matters = (cross_jump == 2); cross_jump_death_matters = (cross_jump == 2);
max_uid = init_label_info (f) + 1;
/* Initialize LABEL_NUSES and JUMP_LABEL fields. Delete any REG_LABEL
notes whose labels don't occur in the insn any more. */
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)
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) > max_uid)
max_uid = INSN_UID (insn);
}
max_uid++;
/* If we are performing cross jump optimizations, then initialize /* If we are performing cross jump optimizations, then initialize
tables mapping UIDs to EH regions to avoid incorrect movement tables mapping UIDs to EH regions to avoid incorrect movement
...@@ -188,26 +171,7 @@ jump_optimize (f, cross_jump, noop_moves, after_regscan) ...@@ -188,26 +171,7 @@ jump_optimize (f, cross_jump, noop_moves, after_regscan)
if (flag_exceptions && cross_jump) if (flag_exceptions && cross_jump)
init_insn_eh_region (f, max_uid); init_insn_eh_region (f, max_uid);
/* Delete insns following barriers, up to next label. */ delete_barrier_successors (f);
for (insn = f; insn;)
{
if (GET_CODE (insn) == BARRIER)
{
insn = NEXT_INSN (insn);
while (insn != 0 && GET_CODE (insn) != CODE_LABEL)
{
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. */
}
else
insn = NEXT_INSN (insn);
}
/* Leave some extra room for labels and duplicate exit test insns /* Leave some extra room for labels and duplicate exit test insns
we make. */ we make. */
...@@ -215,32 +179,7 @@ jump_optimize (f, cross_jump, noop_moves, after_regscan) ...@@ -215,32 +179,7 @@ jump_optimize (f, cross_jump, noop_moves, after_regscan)
jump_chain = (rtx *) alloca (max_jump_chain * sizeof (rtx)); jump_chain = (rtx *) alloca (max_jump_chain * sizeof (rtx));
bzero ((char *) jump_chain, max_jump_chain * sizeof (rtx)); bzero ((char *) jump_chain, max_jump_chain * sizeof (rtx));
/* Mark the label each jump jumps to. mark_all_labels (f, cross_jump);
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. */
for (insn = f; insn; insn = NEXT_INSN (insn))
if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
{
mark_jump_label (PATTERN (insn), insn, cross_jump);
if (! INSN_DELETED_P (insn) && GET_CODE (insn) == JUMP_INSN)
{
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;
}
}
}
/* Keep track of labels used from static data; /* Keep track of labels used from static data;
they cannot ever be deleted. */ they cannot ever be deleted. */
...@@ -258,51 +197,11 @@ jump_optimize (f, cross_jump, noop_moves, after_regscan) ...@@ -258,51 +197,11 @@ jump_optimize (f, cross_jump, noop_moves, after_regscan)
exception_optimize (); exception_optimize ();
/* Delete all labels already not referenced. last_insn = delete_unreferenced_labels (f);
Also find the last insn. */
last_insn = 0;
for (insn = f; insn; )
{
if (GET_CODE (insn) == CODE_LABEL && LABEL_NUSES (insn) == 0)
insn = delete_insn (insn);
else
{
last_insn = insn;
insn = NEXT_INSN (insn);
}
}
if (!optimize) if (!optimize)
{ {
/* See if there is still a NOTE_INSN_FUNCTION_END in this function. can_reach_end = calculate_can_reach_end (last_insn, 1, 0);
If so record that this function can drop off the end. */
insn = last_insn;
{
int n_labels = 1;
while (insn
/* One label can follow the end-note: the return label. */
&& ((GET_CODE (insn) == CODE_LABEL && n_labels-- > 0)
/* Ordinary insns can follow it if returning a structure. */
|| GET_CODE (insn) == INSN
/* If machine uses explicit RETURN insns, no epilogue,
then one of them follows the note. */
|| (GET_CODE (insn) == JUMP_INSN
&& GET_CODE (PATTERN (insn)) == RETURN)
/* A barrier can follow the return insn. */
|| GET_CODE (insn) == BARRIER
/* Other kinds of notes can follow also. */
|| (GET_CODE (insn) == NOTE
&& NOTE_LINE_NUMBER (insn) != NOTE_INSN_FUNCTION_END)))
insn = PREV_INSN (insn);
}
/* Report if control can fall through at the end of the function. */
if (insn && GET_CODE (insn) == NOTE
&& NOTE_LINE_NUMBER (insn) == NOTE_INSN_FUNCTION_END
&& ! INSN_DELETED_P (insn))
can_reach_end = 1;
/* Zero the "deleted" flag of all the "deleted" insns. */ /* Zero the "deleted" flag of all the "deleted" insns. */
for (insn = f; insn; insn = NEXT_INSN (insn)) for (insn = f; insn; insn = NEXT_INSN (insn))
...@@ -333,325 +232,87 @@ jump_optimize (f, cross_jump, noop_moves, after_regscan) ...@@ -333,325 +232,87 @@ jump_optimize (f, cross_jump, noop_moves, after_regscan)
#endif #endif
if (noop_moves) if (noop_moves)
for (insn = f; insn; ) delete_noop_moves (f);
/* If we haven't yet gotten to reload and we have just run regscan,
delete any insn that sets a register that isn't used elsewhere.
This helps some of the optimizations below by having less insns
being jumped around. */
if (! reload_completed && after_regscan)
for (insn = f; insn; insn = next)
{ {
rtx set = single_set (insn);
next = NEXT_INSN (insn); next = NEXT_INSN (insn);
if (GET_CODE (insn) == INSN) if (set && GET_CODE (SET_DEST (set)) == REG
{ && REGNO (SET_DEST (set)) >= FIRST_PSEUDO_REGISTER
register rtx body = PATTERN (insn); && REGNO_FIRST_UID (REGNO (SET_DEST (set))) == INSN_UID (insn)
/* We use regno_last_note_uid so as not to delete the setting
of a reg that's used in notes. A subsequent optimization
might arrange to use that reg for real. */
&& REGNO_LAST_NOTE_UID (REGNO (SET_DEST (set))) == INSN_UID (insn)
&& ! side_effects_p (SET_SRC (set))
&& ! find_reg_note (insn, REG_RETVAL, 0))
delete_insn (insn);
}
/* Combine stack_adjusts with following push_insns. */ /* Now iterate optimizing jumps until nothing changes over one pass. */
#ifdef PUSH_ROUNDING changed = 1;
if (GET_CODE (body) == SET old_max_reg = max_reg_num ();
&& SET_DEST (body) == stack_pointer_rtx while (changed)
&& GET_CODE (SET_SRC (body)) == PLUS
&& XEXP (SET_SRC (body), 0) == stack_pointer_rtx
&& GET_CODE (XEXP (SET_SRC (body), 1)) == CONST_INT
&& INTVAL (XEXP (SET_SRC (body), 1)) > 0)
{ {
rtx p; changed = 0;
rtx stack_adjust_insn = insn;
int stack_adjust_amount = INTVAL (XEXP (SET_SRC (body), 1));
int total_pushed = 0;
int pushes = 0;
/* Find all successive push insns. */ for (insn = f; insn; insn = next)
p = insn;
/* Don't convert more than three pushes;
that starts adding too many displaced addresses
and the whole thing starts becoming a losing
proposition. */
while (pushes < 3)
{ {
rtx pbody, dest; rtx reallabelprev;
p = next_nonnote_insn (p); rtx temp, temp1, temp2, temp3, temp4, temp5, temp6;
if (p == 0 || GET_CODE (p) != INSN) rtx nlabel;
break; int this_is_simplejump, this_is_condjump, reversep = 0;
pbody = PATTERN (p); int this_is_condjump_in_parallel;
if (GET_CODE (pbody) != SET)
break;
dest = SET_DEST (pbody);
/* Allow a no-op move between the adjust and the push. */
if (GET_CODE (dest) == REG
&& GET_CODE (SET_SRC (pbody)) == REG
&& REGNO (dest) == REGNO (SET_SRC (pbody)))
continue;
if (! (GET_CODE (dest) == MEM
&& GET_CODE (XEXP (dest, 0)) == POST_INC
&& XEXP (XEXP (dest, 0), 0) == stack_pointer_rtx))
break;
pushes++;
if (total_pushed + GET_MODE_SIZE (GET_MODE (SET_DEST (pbody)))
> stack_adjust_amount)
break;
total_pushed += GET_MODE_SIZE (GET_MODE (SET_DEST (pbody)));
}
/* Discard the amount pushed from the stack adjust; #if 0
maybe eliminate it entirely. */ /* If NOT the first iteration, if this is the last jump pass
if (total_pushed >= stack_adjust_amount) (just before final), do the special peephole optimizations.
{ Avoiding the first iteration gives ordinary jump opts
delete_computation (stack_adjust_insn); a chance to work before peephole opts. */
total_pushed = stack_adjust_amount;
}
else
XEXP (SET_SRC (PATTERN (stack_adjust_insn)), 1)
= GEN_INT (stack_adjust_amount - total_pushed);
/* Change the appropriate push insns to ordinary stores. */ if (reload_completed && !first && !flag_no_peephole)
p = insn; if (GET_CODE (insn) == INSN || GET_CODE (insn) == JUMP_INSN)
while (total_pushed > 0) peephole (insn);
#endif
/* That could have deleted some insns after INSN, so check now
what the following insn is. */
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
&& simplejump_p (temp1))
{ {
rtx pbody, dest; temp = PREV_INSN (insn);
p = next_nonnote_insn (p); if (duplicate_loop_exit_test (insn))
if (GET_CODE (p) != INSN)
break;
pbody = PATTERN (p);
if (GET_CODE (pbody) != SET)
break;
dest = SET_DEST (pbody);
/* Allow a no-op move between the adjust and the push. */
if (GET_CODE (dest) == REG
&& GET_CODE (SET_SRC (pbody)) == REG
&& REGNO (dest) == REGNO (SET_SRC (pbody)))
continue;
if (! (GET_CODE (dest) == MEM
&& GET_CODE (XEXP (dest, 0)) == POST_INC
&& XEXP (XEXP (dest, 0), 0) == stack_pointer_rtx))
break;
total_pushed -= GET_MODE_SIZE (GET_MODE (SET_DEST (pbody)));
/* If this push doesn't fully fit in the space
of the stack adjust that we deleted,
make another stack adjust here for what we
didn't use up. There should be peepholes
to recognize the resulting sequence of insns. */
if (total_pushed < 0)
{ {
emit_insn_before (gen_add2_insn (stack_pointer_rtx, changed = 1;
GEN_INT (- total_pushed)), next = NEXT_INSN (temp);
p); continue;
break;
}
XEXP (dest, 0)
= plus_constant (stack_pointer_rtx, total_pushed);
} }
} }
#endif
/* Detect and delete no-op move instructions if (GET_CODE (insn) != JUMP_INSN)
resulting from not allocating a parameter in a register. */ continue;
if (GET_CODE (body) == SET this_is_simplejump = simplejump_p (insn);
&& (SET_DEST (body) == SET_SRC (body) this_is_condjump = condjump_p (insn);
|| (GET_CODE (SET_DEST (body)) == MEM this_is_condjump_in_parallel = condjump_in_parallel_p (insn);
&& GET_CODE (SET_SRC (body)) == MEM
&& rtx_equal_p (SET_SRC (body), SET_DEST (body))))
&& ! (GET_CODE (SET_DEST (body)) == MEM
&& MEM_VOLATILE_P (SET_DEST (body)))
&& ! (GET_CODE (SET_SRC (body)) == MEM
&& MEM_VOLATILE_P (SET_SRC (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_PTR, 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_PTR, 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);
}
/* Also delete insns to store bit fields if they are no-ops. */
/* Not worth the hair to detect this in the big-endian case. */
else if (! BYTES_BIG_ENDIAN
&& GET_CODE (body) == SET
&& GET_CODE (SET_DEST (body)) == ZERO_EXTRACT
&& XEXP (SET_DEST (body), 2) == const0_rtx
&& XEXP (SET_DEST (body), 0) == SET_SRC (body)
&& ! (GET_CODE (SET_SRC (body)) == MEM
&& MEM_VOLATILE_P (SET_SRC (body))))
delete_insn (insn);
}
insn = next;
}
/* If we haven't yet gotten to reload and we have just run regscan,
delete any insn that sets a register that isn't used elsewhere.
This helps some of the optimizations below by having less insns
being jumped around. */
if (! reload_completed && after_regscan)
for (insn = f; insn; insn = next)
{
rtx set = single_set (insn);
next = NEXT_INSN (insn);
if (set && GET_CODE (SET_DEST (set)) == REG
&& REGNO (SET_DEST (set)) >= FIRST_PSEUDO_REGISTER
&& REGNO_FIRST_UID (REGNO (SET_DEST (set))) == INSN_UID (insn)
/* We use regno_last_note_uid so as not to delete the setting
of a reg that's used in notes. A subsequent optimization
might arrange to use that reg for real. */
&& REGNO_LAST_NOTE_UID (REGNO (SET_DEST (set))) == INSN_UID (insn)
&& ! side_effects_p (SET_SRC (set))
&& ! find_reg_note (insn, REG_RETVAL, 0))
delete_insn (insn);
}
/* Now iterate optimizing jumps until nothing changes over one pass. */
changed = 1;
old_max_reg = max_reg_num ();
while (changed)
{
changed = 0;
for (insn = f; insn; insn = next)
{
rtx reallabelprev;
rtx temp, temp1, temp2, temp3, temp4, temp5, temp6;
rtx nlabel;
int this_is_simplejump, this_is_condjump, reversep = 0;
int this_is_condjump_in_parallel;
#if 0
/* If NOT the first iteration, if this is the last jump pass
(just before final), do the special peephole optimizations.
Avoiding the first iteration gives ordinary jump opts
a chance to work before peephole opts. */
if (reload_completed && !first && !flag_no_peephole)
if (GET_CODE (insn) == INSN || GET_CODE (insn) == JUMP_INSN)
peephole (insn);
#endif
/* That could have deleted some insns after INSN, so check now
what the following insn is. */
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
&& simplejump_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_simplejump = simplejump_p (insn);
this_is_condjump = condjump_p (insn);
this_is_condjump_in_parallel = condjump_in_parallel_p (insn);
/* Tension the labels in dispatch tables. */ /* Tension the labels in dispatch tables. */
...@@ -2371,39 +2032,448 @@ jump_optimize (f, cross_jump, noop_moves, after_regscan) ...@@ -2371,39 +2032,448 @@ jump_optimize (f, cross_jump, noop_moves, after_regscan)
} }
#endif #endif
/* See if there is still a NOTE_INSN_FUNCTION_END in this function. can_reach_end = calculate_can_reach_end (last_insn, 0, 1);
If so, delete it, and record that this function can drop off the end. */
/* Show JUMP_CHAIN no longer valid. */
jump_chain = 0;
}
/* 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;
insn = last_insn; for (insn = f; insn; insn = NEXT_INSN (insn))
{ {
int n_labels = 1; if (GET_CODE (insn) == CODE_LABEL)
while (insn LABEL_NUSES (insn) = (LABEL_PRESERVE_P (insn) != 0);
/* One label can follow the end-note: the return label. */ else if (GET_CODE (insn) == JUMP_INSN)
&& ((GET_CODE (insn) == CODE_LABEL && n_labels-- > 0) JUMP_LABEL (insn) = 0;
/* Ordinary insns can follow it if returning a structure. */ else if (GET_CODE (insn) == INSN || GET_CODE (insn) == CALL_INSN)
|| GET_CODE (insn) == INSN {
/* If machine uses explicit RETURN insns, no epilogue, rtx note, next;
then one of them follows the note. */
|| (GET_CODE (insn) == JUMP_INSN
&& GET_CODE (PATTERN (insn)) == RETURN)
/* A barrier can follow the return insn. */
|| GET_CODE (insn) == BARRIER
/* Other kinds of notes can follow also. */
|| (GET_CODE (insn) == NOTE
&& NOTE_LINE_NUMBER (insn) != NOTE_INSN_FUNCTION_END)))
insn = PREV_INSN (insn);
}
/* Report if control can fall through at the end of the function. */ for (note = REG_NOTES (insn); note; note = next)
if (insn && GET_CODE (insn) == NOTE
&& NOTE_LINE_NUMBER (insn) == NOTE_INSN_FUNCTION_END)
{ {
can_reach_end = 1; next = XEXP (note, 1);
delete_insn (insn); 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);
} }
/* Show JUMP_CHAIN no longer valid. */ return largest_uid;
jump_chain = 0; }
/* Delete insns following barriers, up to next label. */
static void
delete_barrier_successors (f)
rtx f;
{
rtx insn;
for (insn = f; insn;)
{
if (GET_CODE (insn) == BARRIER)
{
insn = NEXT_INSN (insn);
while (insn != 0 && GET_CODE (insn) != CODE_LABEL)
{
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. */
}
else
insn = NEXT_INSN (insn);
}
}
/* 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. */
static void
mark_all_labels (f, cross_jump)
rtx f;
int cross_jump;
{
rtx insn;
for (insn = f; insn; insn = NEXT_INSN (insn))
if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
{
mark_jump_label (PATTERN (insn), insn, cross_jump);
if (! INSN_DELETED_P (insn) && GET_CODE (insn) == JUMP_INSN)
{
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)
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);
/* Combine stack_adjusts with following push_insns. */
#ifdef PUSH_ROUNDING
if (GET_CODE (body) == SET
&& SET_DEST (body) == stack_pointer_rtx
&& GET_CODE (SET_SRC (body)) == PLUS
&& XEXP (SET_SRC (body), 0) == stack_pointer_rtx
&& GET_CODE (XEXP (SET_SRC (body), 1)) == CONST_INT
&& INTVAL (XEXP (SET_SRC (body), 1)) > 0)
{
rtx p;
rtx stack_adjust_insn = insn;
int stack_adjust_amount = INTVAL (XEXP (SET_SRC (body), 1));
int total_pushed = 0;
int pushes = 0;
/* Find all successive push insns. */
p = insn;
/* Don't convert more than three pushes;
that starts adding too many displaced addresses
and the whole thing starts becoming a losing
proposition. */
while (pushes < 3)
{
rtx pbody, dest;
p = next_nonnote_insn (p);
if (p == 0 || GET_CODE (p) != INSN)
break;
pbody = PATTERN (p);
if (GET_CODE (pbody) != SET)
break;
dest = SET_DEST (pbody);
/* Allow a no-op move between the adjust and the push. */
if (GET_CODE (dest) == REG
&& GET_CODE (SET_SRC (pbody)) == REG
&& REGNO (dest) == REGNO (SET_SRC (pbody)))
continue;
if (! (GET_CODE (dest) == MEM
&& GET_CODE (XEXP (dest, 0)) == POST_INC
&& XEXP (XEXP (dest, 0), 0) == stack_pointer_rtx))
break;
pushes++;
if (total_pushed + GET_MODE_SIZE (GET_MODE (SET_DEST (pbody)))
> stack_adjust_amount)
break;
total_pushed += GET_MODE_SIZE (GET_MODE (SET_DEST (pbody)));
}
/* Discard the amount pushed from the stack adjust;
maybe eliminate it entirely. */
if (total_pushed >= stack_adjust_amount)
{
delete_computation (stack_adjust_insn);
total_pushed = stack_adjust_amount;
}
else
XEXP (SET_SRC (PATTERN (stack_adjust_insn)), 1)
= GEN_INT (stack_adjust_amount - total_pushed);
/* Change the appropriate push insns to ordinary stores. */
p = insn;
while (total_pushed > 0)
{
rtx pbody, dest;
p = next_nonnote_insn (p);
if (GET_CODE (p) != INSN)
break;
pbody = PATTERN (p);
if (GET_CODE (pbody) != SET)
break;
dest = SET_DEST (pbody);
/* Allow a no-op move between the adjust and the push. */
if (GET_CODE (dest) == REG
&& GET_CODE (SET_SRC (pbody)) == REG
&& REGNO (dest) == REGNO (SET_SRC (pbody)))
continue;
if (! (GET_CODE (dest) == MEM
&& GET_CODE (XEXP (dest, 0)) == POST_INC
&& XEXP (XEXP (dest, 0), 0) == stack_pointer_rtx))
break;
total_pushed -= GET_MODE_SIZE (GET_MODE (SET_DEST (pbody)));
/* If this push doesn't fully fit in the space
of the stack adjust that we deleted,
make another stack adjust here for what we
didn't use up. There should be peepholes
to recognize the resulting sequence of insns. */
if (total_pushed < 0)
{
emit_insn_before (gen_add2_insn (stack_pointer_rtx,
GEN_INT (- total_pushed)),
p);
break;
}
XEXP (dest, 0)
= plus_constant (stack_pointer_rtx, total_pushed);
}
}
#endif
/* Detect and delete no-op move instructions
resulting from not allocating a parameter in a register. */
if (GET_CODE (body) == SET
&& (SET_DEST (body) == SET_SRC (body)
|| (GET_CODE (SET_DEST (body)) == MEM
&& GET_CODE (SET_SRC (body)) == MEM
&& rtx_equal_p (SET_SRC (body), SET_DEST (body))))
&& ! (GET_CODE (SET_DEST (body)) == MEM
&& MEM_VOLATILE_P (SET_DEST (body)))
&& ! (GET_CODE (SET_SRC (body)) == MEM
&& MEM_VOLATILE_P (SET_SRC (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_PTR, 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_PTR, 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);
}
/* Also delete insns to store bit fields if they are no-ops. */
/* Not worth the hair to detect this in the big-endian case. */
else if (! BYTES_BIG_ENDIAN
&& GET_CODE (body) == SET
&& GET_CODE (SET_DEST (body)) == ZERO_EXTRACT
&& XEXP (SET_DEST (body), 2) == const0_rtx
&& XEXP (SET_DEST (body), 0) == SET_SRC (body)
&& ! (GET_CODE (SET_SRC (body)) == MEM
&& MEM_VOLATILE_P (SET_SRC (body))))
delete_insn (insn);
}
insn = next;
}
}
/* See if there is still a NOTE_INSN_FUNCTION_END in this function.
If so indicate that this function can drop off the end by returning
1, else return 0.
CHECK_DELETED indicates whether we must check if the note being
searched for has the deleted flag set.
DELETE_FINAL_NOTE indicates whether we should delete the note
if we find it. */
static int
calculate_can_reach_end (last, check_deleted, delete_final_note)
rtx last;
int check_deleted;
int delete_final_note;
{
rtx insn = last;
int n_labels = 1;
while (insn != NULL_RTX)
{
int ok = 0;
/* One label can follow the end-note: the return label. */
if (GET_CODE (insn) == CODE_LABEL && n_labels-- > 0)
ok = 1;
/* Ordinary insns can follow it if returning a structure. */
else if (GET_CODE (insn) == INSN)
ok = 1;
/* If machine uses explicit RETURN insns, no epilogue,
then one of them follows the note. */
else if (GET_CODE (insn) == JUMP_INSN
&& GET_CODE (PATTERN (insn)) == RETURN)
ok = 1;
/* A barrier can follow the return insn. */
else if (GET_CODE (insn) == BARRIER)
ok = 1;
/* Other kinds of notes can follow also. */
else if (GET_CODE (insn) == NOTE
&& NOTE_LINE_NUMBER (insn) != NOTE_INSN_FUNCTION_END)
ok = 1;
if (ok != 1)
break;
insn = PREV_INSN (insn);
}
/* See if we backed up to the appropriate type of note. */
if (insn != NULL_RTX
&& GET_CODE (insn) == NOTE
&& NOTE_LINE_NUMBER (insn) == NOTE_INSN_FUNCTION_END
&& (check_deleted != 0
&& ! INSN_DELETED_P (insn)))
{
if (delete_final_note)
delete_insn (insn);
return 1;
}
return 0;
} }
/* LOOP_START is a NOTE_INSN_LOOP_BEG note that is followed by an unconditional /* LOOP_START is a NOTE_INSN_LOOP_BEG note that is followed by an unconditional
......
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment