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* cse.c (delete_trivially_dead_insn): Don't iterate.

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From-SVN: r94498
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Kazu Hirata 2005-01-31 22:43:36 +00:00 • committed by Kazu Hirata
parent 0530bc70fb
commit 65e9fa1009
2 changed files with 47 additions and 49 deletions
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4
gcc/ChangeLog
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@ -1,3 +1,7 @@
2005-01-31 Kazu Hirata <kazu@cs.umass.edu>
* cse.c (delete_trivially_dead_insn): Don't iterate.
2005-01-31 Andrew Pinski <pinskia@physics.uc.edu>
* config/rs6000/rs6000.md (copysignsf3): New expand.

92
gcc/cse.c
View file

@ -7268,7 +7268,7 @@ delete_trivially_dead_insns (rtx insns, int nreg)
int *counts;
rtx insn, prev;
int in_libcall = 0, dead_libcall = 0;
int ndead = 0, nlastdead, niterations = 0;
int ndead = 0;
timevar_push (TV_DELETE_TRIVIALLY_DEAD);
/* First count the number of times each register is used. */
@ -7276,65 +7276,59 @@ delete_trivially_dead_insns (rtx insns, int nreg)
for (insn = next_real_insn (insns); insn; insn = next_real_insn (insn))
count_reg_usage (insn, counts, 1);
do
/* Go from the last insn to the first and delete insns that only set unused
registers or copy a register to itself. As we delete an insn, remove
usage counts for registers it uses.
The first jump optimization pass may leave a real insn as the last
insn in the function. We must not skip that insn or we may end
up deleting code that is not really dead. */
insn = get_last_insn ();
if (! INSN_P (insn))
insn = prev_real_insn (insn);
for (; insn; insn = prev)
{
nlastdead = ndead;
niterations++;
/* Go from the last insn to the first and delete insns that only set unused
registers or copy a register to itself. As we delete an insn, remove
usage counts for registers it uses.
int live_insn = 0;
The first jump optimization pass may leave a real insn as the last
insn in the function. We must not skip that insn or we may end
up deleting code that is not really dead. */
insn = get_last_insn ();
if (! INSN_P (insn))
insn = prev_real_insn (insn);
prev = prev_real_insn (insn);
for (; insn; insn = prev)
/* Don't delete any insns that are part of a libcall block unless
we can delete the whole libcall block.
Flow or loop might get confused if we did that. Remember
that we are scanning backwards. */
if (find_reg_note (insn, REG_RETVAL, NULL_RTX))
{
int live_insn = 0;
in_libcall = 1;
live_insn = 1;
dead_libcall = dead_libcall_p (insn, counts);
}
else if (in_libcall)
live_insn = ! dead_libcall;
else
live_insn = insn_live_p (insn, counts);
prev = prev_real_insn (insn);
/* If this is a dead insn, delete it and show registers in it aren't
being used. */
/* Don't delete any insns that are part of a libcall block unless
we can delete the whole libcall block.
if (! live_insn)
{
count_reg_usage (insn, counts, -1);
delete_insn_and_edges (insn);
ndead++;
}
Flow or loop might get confused if we did that. Remember
that we are scanning backwards. */
if (find_reg_note (insn, REG_RETVAL, NULL_RTX))
{
in_libcall = 1;
live_insn = 1;
dead_libcall = dead_libcall_p (insn, counts);
}
else if (in_libcall)
live_insn = ! dead_libcall;
else
live_insn = insn_live_p (insn, counts);
/* If this is a dead insn, delete it and show registers in it aren't
being used. */
if (! live_insn)
{
count_reg_usage (insn, counts, -1);
delete_insn_and_edges (insn);
ndead++;
}
if (find_reg_note (insn, REG_LIBCALL, NULL_RTX))
{
in_libcall = 0;
dead_libcall = 0;
}
if (find_reg_note (insn, REG_LIBCALL, NULL_RTX))
{
in_libcall = 0;
dead_libcall = 0;
}
}
while (ndead != nlastdead);
if (dump_file && ndead)
fprintf (dump_file, "Deleted %i trivially dead insns; %i iterations\n",
ndead, niterations);
fprintf (dump_file, "Deleted %i trivially dead insns\n",
ndead);
/* Clean up. */
free (counts);
timevar_pop (TV_DELETE_TRIVIALLY_DEAD);