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loop.h (express_from): Declare.

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* loop.h (express_from): Declare.
	(struct induction): Replace derived flag with derived_from pointer.
	* loop.c (strength_reduce, record_giv, recombine_givs): Likewise.
	(express_from): No longer static.
	* unroll.c (find_splittable_givs): Replace derived with derived_from.
	When processing an address giv with which another giv has been
	combined that has also been derived from a third giv, handle like
	having combined with the third giv.
	Set splittable_regs_updates appropriately for derived givs.

From-SVN: r25007
This commit is contained in:
J"orn Rennecke 1999-02-03 12:48:48 +00:00 • committed by Joern Rennecke
parent 6ebec6eed4
commit 4d87f7a77c
4 changed files with 68 additions and 16 deletions
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12
gcc/ChangeLog
View file

@ -1,3 +1,15 @@
Wed Feb 3 20:44:59 1999 J"orn Rennecke <amylaar@cygnus.co.uk>
* loop.h (express_from): Declare.
(struct induction): Replace derived flag with derived_from pointer.
* loop.c (strength_reduce, record_giv, recombine_givs): Likewise.
(express_from): No longer static.
* unroll.c (find_splittable_givs): Replace derived with derived_from.
When processing an address giv with which another giv has been
combined that has also been derived from a third giv, handle like
having combined with the third giv.
Set splittable_regs_updates appropriately for derived givs.
Wed Feb 3 15:26:58 1999 Gavin Romig-Koch <gavin@cygnus.com>
* config/mips/mips.md (div_trap_mips16): Remove nop's after branches.

13
gcc/loop.c
View file

@ -320,7 +320,6 @@ static int general_induction_var PROTO((rtx, rtx *, rtx *, rtx *, int, int *));
static int consec_sets_giv PROTO((int, rtx, rtx, rtx, rtx *, rtx *, rtx *));
static int check_dbra_loop PROTO((rtx, int, rtx, struct loop_info *));
static rtx express_from_1 PROTO((rtx, rtx, rtx));
static rtx express_from PROTO((struct induction *, struct induction *));
static rtx combine_givs_p PROTO((struct induction *, struct induction *));
static void combine_givs PROTO((struct iv_class *));
struct recombine_givs_stats;
@ -4180,7 +4179,7 @@ strength_reduce (scan_start, end, loop_top, insn_count,
v->auto_inc_opt = 0;
v->unrolled = 0;
v->shared = 0;
v->derived = 0;
v->derived_from = 0;
v->always_computable = 1;
v->always_executed = 1;
v->replaceable = 1;
@ -4622,7 +4621,7 @@ strength_reduce (scan_start, end, loop_top, insn_count,
v->new_reg = gen_reg_rtx (v->mode);
if (v->derived)
if (v->derived_from)
{
PATTERN (v->insn)
= replace_rtx (PATTERN (v->insn), v->dest_reg, v->new_reg);
@ -5273,7 +5272,7 @@ record_giv (v, insn, src_reg, dest_reg, mult_val, add_val, benefit,
v->auto_inc_opt = 0;
v->unrolled = 0;
v->shared = 0;
v->derived = 0;
v->derived_from = 0;
v->last_use = 0;
/* The v->always_computable field is used in update_giv_derive, to
@ -6632,7 +6631,7 @@ express_from_1 (a, b, mult)
return NULL_RTX;
}
static rtx
rtx
express_from (g1, g2)
struct induction *g1, *g2;
{
@ -7290,7 +7289,7 @@ recombine_givs (bl, loop_start, loop_end, unroll_p)
rtx sum;
v = giv_array[stats[i].giv_number];
if (v->giv_type != DEST_REG || v->derived || v->same)
if (v->giv_type != DEST_REG || v->derived_from || v->same)
continue;
if (! last_giv)
{
@ -7347,7 +7346,7 @@ recombine_givs (bl, loop_start, loop_end, unroll_p)
gen_rtx_SET (GET_MODE (v->dest_reg),
v->dest_reg, sum), 0))
{
v->derived = 1;
v->derived_from = last_giv;
v->new_reg = v->dest_reg;
life_end = stats[i].end_luid;

5
gcc/loop.h
View file

@ -101,8 +101,6 @@ struct induction
initialized in unrolled loop. */
unsigned shared : 1;
unsigned no_const_addval : 1; /* 1 if add_val does not contain a const. */
unsigned derived : 1; /* For a giv, 1 if we decided to derive this
giv from another one. */
int lifetime; /* Length of life of this giv */
rtx derive_adjustment; /* If nonzero, is an adjustment to be
subtracted from add_val when this giv
@ -115,6 +113,8 @@ struct induction
struct induction *same; /* If this giv has been combined with another
giv, this points to the base giv. The base
giv will have COMBINED_WITH non-zero. */
struct induction *derived_from;/* For a giv, if we decided to derive this
giv from another one. */
HOST_WIDE_INT const_adjust; /* Used by loop unrolling, when an address giv
is split, and a constant is eliminated from
the address, the -constant is stored here
@ -226,6 +226,7 @@ extern int first_increment_giv, last_increment_giv;
int invariant_p PROTO((rtx));
rtx get_condition_for_loop PROTO((rtx));
void emit_iv_add_mult PROTO((rtx, rtx, rtx, rtx, rtx));
rtx express_from PROTO((struct induction *, struct induction *));
/* Forward declarations for non-static functions declared in stmt.c. */
void find_loop_tree_blocks PROTO((void));

54
gcc/unroll.c
View file

@ -1794,6 +1794,10 @@ copy_loop_body (copy_start, copy_end, map, exit_label, last_iteration,
giv_dest_reg = SET_DEST (set);
if (derived_regs[regno])
{
/* ??? This relies on SET_SRC (SET) to be of
the form (plus (reg) (const_int)), and thus
forces recombine_givs to restrict the kind
of giv derivations it does before unrolling. */
giv_src_reg = XEXP (SET_SRC (set), 0);
giv_inc = XEXP (SET_SRC (set), 1);
}
@ -2830,7 +2834,7 @@ find_splittable_givs (bl, unroll_type, loop_start, loop_end, increment,
}
splittable_regs[REGNO (v->new_reg)] = value;
derived_regs[REGNO (v->new_reg)] = v->derived;
derived_regs[REGNO (v->new_reg)] = v->derived_from != 0;
}
else
{
@ -2886,17 +2890,36 @@ find_splittable_givs (bl, unroll_type, loop_start, loop_end, increment,
Emit insn to initialize its value before loop start. */
rtx tem = gen_reg_rtx (v->mode);
struct induction *same = v->same;
rtx new_reg = v->new_reg;
record_base_value (REGNO (tem), v->add_val, 0);
if (same && same->derived_from)
{
/* calculate_giv_inc doesn't work for derived givs.
copy_loop_body works around the problem for the
DEST_REG givs themselves, but it can't handle
DEST_ADDR givs that have been combined with
derived a derived DEST_REG giv.
So Handle V as if the giv from which V->SAME has
been derived has been combined with V.
recombine_givs only derives givs from givs that
are reduced the ordinary, so we need not worry
about same->derived_from being in turn derived. */
same = same->derived_from;
new_reg = express_from (same, v);
}
/* If the address giv has a constant in its new_reg value,
then this constant can be pulled out and put in value,
instead of being part of the initialization code. */
if (GET_CODE (v->new_reg) == PLUS
&& GET_CODE (XEXP (v->new_reg, 1)) == CONST_INT)
if (GET_CODE (new_reg) == PLUS
&& GET_CODE (XEXP (new_reg, 1)) == CONST_INT)
{
v->dest_reg
= plus_constant (tem, INTVAL (XEXP (v->new_reg,1)));
= plus_constant (tem, INTVAL (XEXP (new_reg, 1)));
/* Only succeed if this will give valid addresses.
Try to validate both the first and the last
@ -2907,9 +2930,9 @@ find_splittable_givs (bl, unroll_type, loop_start, loop_end, increment,
/* Save the negative of the eliminated const, so
that we can calculate the dest_reg's increment
value later. */
v->const_adjust = - INTVAL (XEXP (v->new_reg, 1));
v->const_adjust = - INTVAL (XEXP (new_reg, 1));
v->new_reg = XEXP (v->new_reg, 0);
new_reg = XEXP (new_reg, 0);
if (loop_dump_stream)
fprintf (loop_dump_stream,
"Eliminating constant from giv %d\n",
@ -2938,6 +2961,9 @@ find_splittable_givs (bl, unroll_type, loop_start, loop_end, increment,
INSN_UID (v->insn));
continue;
}
v->new_reg = new_reg;
v->same = same;
/* We set this after the address check, to guarantee that
the register will be initialized. */
@ -2992,6 +3018,15 @@ find_splittable_givs (bl, unroll_type, loop_start, loop_end, increment,
INSN_UID (v->insn));
continue;
}
if (v->same && v->same->derived_from)
{
/* Handle V as if the giv from which V->SAME has
been derived has been combined with V. */
v->same = v->same->derived_from;
v->new_reg = express_from (v->same, v);
}
}
/* Store the value of dest_reg into the insn. This sharing
@ -3014,7 +3049,7 @@ find_splittable_givs (bl, unroll_type, loop_start, loop_end, increment,
Make sure that it's giv is marked as splittable here. */
splittable_regs[REGNO (v->new_reg)] = value;
derived_regs[REGNO (v->new_reg)] = v->derived;
derived_regs[REGNO (v->new_reg)] = v->derived_from != 0;
/* Make it appear to depend upon itself, so that the
giv will be properly split in the main loop above. */
@ -3058,6 +3093,11 @@ find_splittable_givs (bl, unroll_type, loop_start, loop_end, increment,
if (! v->ignore)
count = reg_biv_class[REGNO (v->src_reg)]->biv_count;
if (count > 1 && v->derived_from)
/* In this case, there is one set where the giv insn was and one
set each after each biv increment. (Most are likely dead.) */
count++;
splittable_regs_updates[REGNO (v->new_reg)] = count;
}