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re PR rtl-optimization/83496 (wrong code generated with -Os -mbranch-cost=1)

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PR rtl-optimization/83496
	* reorg.c (steal_delay_list_from_target): Change REDUNDANT array from
	booleans to RTXes.  Call fix_reg_dead_note on every non-null element.
	(steal_delay_list_from_fallthrough): Call fix_reg_dead_note on a
	redundant insn, if any.
	(relax_delay_slots): Likewise.
	(update_reg_unused_notes): Rename REDUNDANT_INSN to OTHER_INSN.

From-SVN: r257996
This commit is contained in:
Eric Botcazou 2018-02-26 16:29:30 +00:00 committed by Eric Botcazou
parent d99dcb77bb
commit f41881a4ad
4 changed files with 36 additions and 17 deletions
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10
gcc/ChangeLog
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@ -1,3 +1,13 @@
2018-02-26 Eric Botcazou <ebotcazou@adacore.com>
PR rtl-optimization/83496
* reorg.c (steal_delay_list_from_target): Change REDUNDANT array from
booleans to RTX. Call fix_reg_dead_note on every non-null element.
(steal_delay_list_from_fallthrough): Call fix_reg_dead_note on a
redundant insn, if any.
(relax_delay_slots): Likewise.
(update_reg_unused_notes): Rename REDUNDANT_INSN to OTHER_INSN.
2018-02-26 Richard Sandiford <richard.sandiford@linaro.org>
PR tree-optimization/83965

38
gcc/reorg.c
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@ -1036,7 +1036,8 @@ check_annul_list_true_false (int annul_true_p,
static void
steal_delay_list_from_target (rtx_insn *insn, rtx condition, rtx_sequence *seq,
vec<rtx_insn *> *delay_list, resources *sets,
vec<rtx_insn *> *delay_list,
struct resources *sets,
struct resources *needed,
struct resources *other_needed,
int slots_to_fill, int *pslots_filled,
@ -1049,7 +1050,7 @@ steal_delay_list_from_target (rtx_insn *insn, rtx condition, rtx_sequence *seq,
int used_annul = 0;
int i;
struct resources cc_set;
bool *redundant;
rtx_insn **redundant;
/* We can't do anything if there are more delay slots in SEQ than we
can handle, or if we don't know that it will be a taken branch.
@ -1088,7 +1089,7 @@ steal_delay_list_from_target (rtx_insn *insn, rtx condition, rtx_sequence *seq,
if (! targetm.can_follow_jump (insn, seq->insn (0)))
return;
redundant = XALLOCAVEC (bool, XVECLEN (seq, 0));
redundant = XALLOCAVEC (rtx_insn *, XVECLEN (seq, 0));
for (i = 1; i < seq->len (); i++)
{
rtx_insn *trial = seq->insn (i);
@ -1152,7 +1153,10 @@ steal_delay_list_from_target (rtx_insn *insn, rtx condition, rtx_sequence *seq,
we therefore decided not to copy. */
for (i = 1; i < seq->len (); i++)
if (redundant[i])
update_block (seq->insn (i), insn);
{
fix_reg_dead_note (redundant[i], insn);
update_block (seq->insn (i), insn);
}
/* Show the place to which we will be branching. */
*pnew_thread = first_active_target_insn (JUMP_LABEL (seq->insn (0)));
@ -1199,6 +1203,7 @@ steal_delay_list_from_fallthrough (rtx_insn *insn, rtx condition,
for (i = 1; i < seq->len (); i++)
{
rtx_insn *trial = seq->insn (i);
rtx_insn *prior_insn;
/* If TRIAL sets CC0, stealing it will move it too far from the use
of CC0. */
@ -1210,8 +1215,9 @@ steal_delay_list_from_fallthrough (rtx_insn *insn, rtx condition,
break;
/* If this insn was already done, we don't need it. */
if (redundant_insn (trial, insn, *delay_list))
if ((prior_insn = redundant_insn (trial, insn, *delay_list)))
{
fix_reg_dead_note (prior_insn, insn);
update_block (trial, insn);
delete_from_delay_slot (trial);
continue;
@ -1791,15 +1797,14 @@ fix_reg_dead_note (rtx_insn *start_insn, rtx stop_insn)
}
}
/* Delete any REG_UNUSED notes that exist on INSN but not on REDUNDANT_INSN.
/* Delete any REG_UNUSED notes that exist on INSN but not on OTHER_INSN.
This handles the case of udivmodXi4 instructions which optimize their
output depending on whether any REG_UNUSED notes are present.
we must make sure that INSN calculates as many results as REDUNDANT_INSN
does. */
output depending on whether any REG_UNUSED notes are present. We must
make sure that INSN calculates as many results as OTHER_INSN does. */
static void
update_reg_unused_notes (rtx_insn *insn, rtx redundant_insn)
update_reg_unused_notes (rtx_insn *insn, rtx other_insn)
{
rtx link, next;
@ -1811,8 +1816,7 @@ update_reg_unused_notes (rtx_insn *insn, rtx redundant_insn)
|| !REG_P (XEXP (link, 0)))
continue;
if (! find_regno_note (redundant_insn, REG_UNUSED,
REGNO (XEXP (link, 0))))
if (!find_regno_note (other_insn, REG_UNUSED, REGNO (XEXP (link, 0))))
remove_note (insn, link);
}
}
@ -2325,9 +2329,8 @@ follow_jumps (rtx label, rtx_insn *jump, bool *crossing)
taken and THREAD_IF_TRUE is set. This is used for the branch at the
end of a loop back up to the top.
OWN_THREAD and OWN_OPPOSITE_THREAD are true if we are the only user of the
thread. I.e., it is the fallthrough code of our jump or the target of the
jump when we are the only jump going there.
OWN_THREAD is true if we are the only user of the thread, i.e. it is
the target of the jump when we are the only jump going there.
If OWN_THREAD is false, it must be the "true" thread of a jump. In that
case, we can only take insns from the head of the thread for our delay
@ -3118,7 +3121,7 @@ relax_delay_slots (rtx_insn *first)
/* Look at every JUMP_INSN and see if we can improve it. */
for (insn = first; insn; insn = next)
{
rtx_insn *other;
rtx_insn *other, *prior_insn;
bool crossing;
next = next_active_insn (insn);
@ -3224,8 +3227,9 @@ relax_delay_slots (rtx_insn *first)
/* See if the first insn in the delay slot is redundant with some
previous insn. Remove it from the delay slot if so; then set up
to reprocess this insn. */
if (redundant_insn (pat->insn (1), delay_insn, vNULL))
if ((prior_insn = redundant_insn (pat->insn (1), delay_insn, vNULL)))
{
fix_reg_dead_note (prior_insn, insn);
update_block (pat->insn (1), insn);
delete_from_delay_slot (pat->insn (1));
next = prev_active_insn (next);

4
gcc/testsuite/ChangeLog
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@ -1,3 +1,7 @@
2018-02-26 Eric Botcazou <ebotcazou@adacore.com>
* gcc.c-torture/execute/20180226-1.c: New test.
2018-02-26 Richard Sandiford <richard.sandiford@linaro.org>
PR tree-optimization/83965

1
gcc/testsuite/gcc.c-torture/execute/20180226-1.c Symbolic link
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@ -0,0 +1 @@
/home/eric/build/gcc/mips-linux/pr83496.c