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Commit 4bbae09f by Ian Lance Taylor Committed by Ian Lance Taylor
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re PR rtl-optimization/13931 (combiner much slower on big basic blocks) 

	PR rtl-optimization/13931
	* combine.c: Revert patch of 2003-05-14, and:
	(try_combine): Only set elim_i1 and elim_i2 if the destination is
	completely killed in the appropriate insn.
	(distribute_notes): Don't skip multiple hard register test for
	elim_i1 and elim_i2.

From-SVN: r105275
parent a2694f68
Showing with 66 additions and 18 deletions
gcc/ChangeLog
2005-10-11 Ian Lance Taylor <ian@airs.com>
PR rtl-optimization/13931
* combine.c: Revert patch of 2003-05-14, and:
(try_combine): Only set elim_i1 and elim_i2 if the destination is
completely killed in the appropriate insn.
(distribute_notes): Don't skip multiple hard register test for
elim_i1 and elim_i2.
2005-10-11 Richard Henderson <rth@redhat.com>
PR c/24255
......
gcc/combine.c
......@@ -53,6 +53,10 @@ Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
flow.c aren't completely updated:
- reg_live_length is not updated
- reg_n_refs is not adjusted in the rare case when a register is
no longer required in a computation
- there are extremely rare cases (see distribute_regnotes) when a
REG_DEAD note is lost
- a LOG_LINKS entry that refers to an insn with multiple SETs may be
removed because there is no way to know which register it was
linking
......@@ -410,7 +414,7 @@ static void reg_dead_at_p_1 (rtx, rtx, void *);
static int reg_dead_at_p (rtx, rtx);
static void move_deaths (rtx, rtx, int, rtx, rtx *);
static int reg_bitfield_target_p (rtx, rtx);
static void distribute_notes (rtx, rtx, rtx, rtx);
static void distribute_notes (rtx, rtx, rtx, rtx, rtx, rtx);
static void distribute_links (rtx);
static void mark_used_regs_combine (rtx);
static int insn_cuid (rtx);
......@@ -1730,6 +1734,7 @@ try_combine (rtx i3, rtx i2, rtx i1, int *new_direct_jump_p)
rtx i2pat;
/* Indicates if I2DEST or I1DEST is in I2SRC or I1_SRC. */
int i2dest_in_i2src = 0, i1dest_in_i1src = 0, i2dest_in_i1src = 0;
int i2dest_killed = 0, i1dest_killed = 0;
int i1_feeds_i3 = 0;
/* Notes that must be added to REG_NOTES in I3 and I2. */
rtx new_i3_notes, new_i2_notes;
......@@ -1838,6 +1843,7 @@ try_combine (rtx i3, rtx i2, rtx i1, int *new_direct_jump_p)
added_sets_2 = added_sets_1 = 0;
i2dest = SET_SRC (PATTERN (i3));
i2dest_killed = dead_or_set_p (i2, i2dest);
/* Replace the dest in I2 with our dest and make the resulting
insn the new pattern for I3. Then skip to where we
......@@ -1912,6 +1918,7 @@ try_combine (rtx i3, rtx i2, rtx i1, int *new_direct_jump_p)
subst_low_cuid = INSN_CUID (i2);
added_sets_2 = added_sets_1 = 0;
i2dest = SET_DEST (temp);
i2dest_killed = dead_or_set_p (i2, i2dest);
SUBST (SET_SRC (temp),
immed_double_const (lo, hi, GET_MODE (SET_DEST (temp))));
......@@ -1982,6 +1989,8 @@ try_combine (rtx i3, rtx i2, rtx i1, int *new_direct_jump_p)
i2dest_in_i2src = reg_overlap_mentioned_p (i2dest, i2src);
i1dest_in_i1src = i1 && reg_overlap_mentioned_p (i1dest, i1src);
i2dest_in_i1src = i1 && reg_overlap_mentioned_p (i2dest, i1src);
i2dest_killed = dead_or_set_p (i2, i2dest);
i1dest_killed = i1 && dead_or_set_p (i1, i1dest);
/* See if I1 directly feeds into I3. It does if I1DEST is not used
in I2SRC. */
......@@ -2737,7 +2746,7 @@ try_combine (rtx i3, rtx i2, rtx i1, int *new_direct_jump_p)
REG_N_DEATHS (REGNO (XEXP (note, 0)))++;
distribute_notes (new_other_notes, undobuf.other_insn,
undobuf.other_insn, NULL_RTX);
undobuf.other_insn, NULL_RTX, NULL_RTX, NULL_RTX);
}
#ifdef HAVE_cc0
/* If I2 is the CC0 setter and I3 is the CC0 user then check whether
......@@ -2812,6 +2821,17 @@ try_combine (rtx i3, rtx i2, rtx i1, int *new_direct_jump_p)
rtx i3links, i2links, i1links = 0;
rtx midnotes = 0;
unsigned int regno;
/* Compute which registers we expect to eliminate. newi2pat may be setting
either i3dest or i2dest, so we must check it. Also, i1dest may be the
same as i3dest, in which case newi2pat may be setting i1dest. */
rtx elim_i2 = ((newi2pat && reg_set_p (i2dest, newi2pat))
|| i2dest_in_i2src || i2dest_in_i1src
|| !i2dest_killed
? 0 : i2dest);
rtx elim_i1 = (i1 == 0 || i1dest_in_i1src
|| (newi2pat && reg_set_p (i1dest, newi2pat))
|| !i1dest_killed
? 0 : i1dest);
/* Get the old REG_NOTES and LOG_LINKS from all our insns and
clear them. */
......@@ -2936,13 +2956,17 @@ try_combine (rtx i3, rtx i2, rtx i1, int *new_direct_jump_p)
/* Distribute all the LOG_LINKS and REG_NOTES from I1, I2, and I3. */
if (i3notes)
distribute_notes (i3notes, i3, i3, newi2pat ? i2 : NULL_RTX);
distribute_notes (i3notes, i3, i3, newi2pat ? i2 : NULL_RTX,
elim_i2, elim_i1);
if (i2notes)
distribute_notes (i2notes, i2, i3, newi2pat ? i2 : NULL_RTX);
distribute_notes (i2notes, i2, i3, newi2pat ? i2 : NULL_RTX,
elim_i2, elim_i1);
if (i1notes)
distribute_notes (i1notes, i1, i3, newi2pat ? i2 : NULL_RTX);
distribute_notes (i1notes, i1, i3, newi2pat ? i2 : NULL_RTX,
elim_i2, elim_i1);
if (midnotes)
distribute_notes (midnotes, NULL_RTX, i3, newi2pat ? i2 : NULL_RTX);
distribute_notes (midnotes, NULL_RTX, i3, newi2pat ? i2 : NULL_RTX,
elim_i2, elim_i1);
/* Distribute any notes added to I2 or I3 by recog_for_combine. We
know these are REG_UNUSED and want them to go to the desired insn,
......@@ -2955,7 +2979,7 @@ try_combine (rtx i3, rtx i2, rtx i1, int *new_direct_jump_p)
if (REG_P (XEXP (temp, 0)))
REG_N_DEATHS (REGNO (XEXP (temp, 0)))++;
distribute_notes (new_i2_notes, i2, i2, NULL_RTX);
distribute_notes (new_i2_notes, i2, i2, NULL_RTX, NULL_RTX, NULL_RTX);
}
if (new_i3_notes)
......@@ -2964,7 +2988,7 @@ try_combine (rtx i3, rtx i2, rtx i1, int *new_direct_jump_p)
if (REG_P (XEXP (temp, 0)))
REG_N_DEATHS (REGNO (XEXP (temp, 0)))++;
distribute_notes (new_i3_notes, i3, i3, NULL_RTX);
distribute_notes (new_i3_notes, i3, i3, NULL_RTX, NULL_RTX, NULL_RTX);
}
/* If I3DEST was used in I3SRC, it really died in I3. We may need to
......@@ -2982,11 +3006,12 @@ try_combine (rtx i3, rtx i2, rtx i1, int *new_direct_jump_p)
if (newi2pat && reg_set_p (i3dest_killed, newi2pat))
distribute_notes (gen_rtx_EXPR_LIST (REG_DEAD, i3dest_killed,
NULL_RTX),
NULL_RTX, i2, NULL_RTX);
NULL_RTX, i2, NULL_RTX, elim_i2, elim_i1);
else
distribute_notes (gen_rtx_EXPR_LIST (REG_DEAD, i3dest_killed,
NULL_RTX),
NULL_RTX, i3, newi2pat ? i2 : NULL_RTX);
NULL_RTX, i3, newi2pat ? i2 : NULL_RTX,
elim_i2, elim_i1);
}
if (i2dest_in_i2src)
......@@ -2996,10 +3021,11 @@ try_combine (rtx i3, rtx i2, rtx i1, int *new_direct_jump_p)
if (newi2pat && reg_set_p (i2dest, newi2pat))
distribute_notes (gen_rtx_EXPR_LIST (REG_DEAD, i2dest, NULL_RTX),
NULL_RTX, i2, NULL_RTX);
NULL_RTX, i2, NULL_RTX, NULL_RTX, NULL_RTX);
else
distribute_notes (gen_rtx_EXPR_LIST (REG_DEAD, i2dest, NULL_RTX),
NULL_RTX, i3, newi2pat ? i2 : NULL_RTX);
NULL_RTX, i3, newi2pat ? i2 : NULL_RTX,
NULL_RTX, NULL_RTX);
}
if (i1dest_in_i1src)
......@@ -3009,10 +3035,11 @@ try_combine (rtx i3, rtx i2, rtx i1, int *new_direct_jump_p)
if (newi2pat && reg_set_p (i1dest, newi2pat))
distribute_notes (gen_rtx_EXPR_LIST (REG_DEAD, i1dest, NULL_RTX),
NULL_RTX, i2, NULL_RTX);
NULL_RTX, i2, NULL_RTX, NULL_RTX, NULL_RTX);
else
distribute_notes (gen_rtx_EXPR_LIST (REG_DEAD, i1dest, NULL_RTX),
NULL_RTX, i3, newi2pat ? i2 : NULL_RTX);
NULL_RTX, i3, newi2pat ? i2 : NULL_RTX,
NULL_RTX, NULL_RTX);
}
distribute_links (i3links);
......@@ -11906,11 +11933,16 @@ reg_bitfield_target_p (rtx x, rtx body)
as appropriate. I3 and I2 are the insns resulting from the combination
insns including FROM (I2 may be zero).
ELIM_I2 and ELIM_I1 are either zero or registers that we know will
not need REG_DEAD notes because they are being substituted for. This
saves searching in the most common cases.
Each note in the list is either ignored or placed on some insns, depending
on the type of note. */
static void
distribute_notes (rtx notes, rtx from_insn, rtx i3, rtx i2)
distribute_notes (rtx notes, rtx from_insn, rtx i3, rtx i2, rtx elim_i2,
rtx elim_i1)
{
rtx note, next_note;
rtx tem;
......@@ -12188,6 +12220,11 @@ distribute_notes (rtx notes, rtx from_insn, rtx i3, rtx i2)
&& reg_referenced_p (XEXP (note, 0), PATTERN (i2)))
place = i2;
if (place == 0
&& (rtx_equal_p (XEXP (note, 0), elim_i2)
|| rtx_equal_p (XEXP (note, 0), elim_i1)))
break;
if (place == 0)
{
basic_block bb = this_basic_block;
......@@ -12249,7 +12286,8 @@ distribute_notes (rtx notes, rtx from_insn, rtx i3, rtx i2)
PATTERN (tem) = pc_rtx;
REG_NOTES (tem) = NULL;
distribute_notes (old_notes, tem, tem, NULL_RTX);
distribute_notes (old_notes, tem, tem, NULL_RTX,
NULL_RTX, NULL_RTX);
distribute_links (LOG_LINKS (tem));
SET_INSN_DELETED (tem);
......@@ -12263,7 +12301,8 @@ distribute_notes (rtx notes, rtx from_insn, rtx i3, rtx i2)
REG_NOTES (cc0_setter) = NULL;
distribute_notes (old_notes, cc0_setter,
cc0_setter, NULL_RTX);
cc0_setter, NULL_RTX,
NULL_RTX, NULL_RTX);
distribute_links (LOG_LINKS (cc0_setter));
SET_INSN_DELETED (cc0_setter);
......@@ -12398,7 +12437,7 @@ distribute_notes (rtx notes, rtx from_insn, rtx i3, rtx i2)
= gen_rtx_EXPR_LIST (REG_DEAD, piece, NULL_RTX);
distribute_notes (new_note, place, place,
NULL_RTX);
NULL_RTX, NULL_RTX, NULL_RTX);
}
else if (! refers_to_regno_p (i, i + 1,
PATTERN (place), 0)
......
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