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riscv-gcc-1
Commit 45f97e2e by Richard Henderson Committed by Richard Henderson
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loop.h (struct induction): Add no_const_addval. 

        * loop.h (struct induction): Add no_const_addval.
        * loop.c (the_movables, reg_address_cost): New variables.
        (init_loop): Init reg_address_cost.
        (loop_optimize): Call end_alias_analysis.
        (scan_loop): Init the_movables.
        (record_giv): Init induction->no_const_addval.
        (basic_induction_var) [PLUS]: Use rtx_equal_p instead of ==.
        [REG]: Rearrange loop search test to catch more cases.
        (general_induction_var): Return success not benefit; take an extra
        argument for that.  Change all callers.
        (simplify_giv_expr) [PLUS]: Always combine invariants.  Use sge_plus.
        [MULT]: Use rtx_equal_p instead of ==.  Combine simple invariants.
        [default]: Search the_movables for additional combinations.
        (sge_plus_constant, sge_plus): New functions.
        (express_from_1): New function.
        (express_from): Always define.  Rewrite using express_from_1.
        (combine_givs_p): Handle more cases.  Ignore address cost.
        (cmp_combine_givs_stats): New function.
        (combine_givs_used_once, combine_givs_benefit_from): New functions.
        (combine_givs): Rewrite to do best-fit combination.
        * fold-const.c (operand_equal_p): Handle RTL_EXPR.
        (fold): Do a complete (A*C)+(B*C) association check.

From-SVN: r21263
parent d4c011bc
Showing with 636 additions and 168 deletions
gcc/ChangeLog
Fri Jul 17 14:18:14 1998 Richard Henderson <rth@cygnus.com>
* loop.h (struct induction): Add no_const_addval.
* loop.c (the_movables, reg_address_cost): New variables.
(init_loop): Init reg_address_cost.
(loop_optimize): Call end_alias_analysis.
(scan_loop): Init the_movables.
(record_giv): Init induction->no_const_addval.
(basic_induction_var) [PLUS]: Use rtx_equal_p instead of ==.
[REG]: Rearrange loop search test to catch more cases.
(general_induction_var): Return success not benefit; take an extra
argument for that. Change all callers.
(simplify_giv_expr) [PLUS]: Always combine invariants. Use sge_plus.
[MULT]: Use rtx_equal_p instead of ==. Combine simple invariants.
[default]: Search the_movables for additional combinations.
(sge_plus_constant, sge_plus): New functions.
(express_from_1): New function.
(express_from): Always define. Rewrite using express_from_1.
(combine_givs_p): Handle more cases. Ignore address cost.
(cmp_combine_givs_stats): New function.
(combine_givs_used_once, combine_givs_benefit_from): New functions.
(combine_givs): Rewrite to do best-fit combination.
* fold-const.c (operand_equal_p): Handle RTL_EXPR.
(fold): Do a complete (A*C)+(B*C) association check.
Fri Jul 17 11:21:55 1998 Jim Wilson <wilson@cygnus.com>
* function.c (fixup_var_refs_insns): Handle CLOBBER of a CONCAT.
......
gcc/fold-const.c
......@@ -1929,6 +1929,11 @@ operand_equal_p (arg0, arg1, only_const)
return 0;
}
case 'e':
if (TREE_CODE (arg0) == RTL_EXPR)
return rtx_equal_p (RTL_EXPR_RTL (arg0), RTL_EXPR_RTL (arg1));
return 0;
default:
return 0;
}
......@@ -4413,18 +4418,36 @@ fold (expr)
goto bit_ior;
}
/* (A * C) + (B * C) -> (A+B) * C. Since we are most concerned
about the case where C is a constant, just try one of the
four possibilities. */
if (TREE_CODE (arg0) == MULT_EXPR && TREE_CODE (arg1) == MULT_EXPR)
{
tree arg00, arg01, arg10, arg11;
tree alt0, alt1, same;
if (TREE_CODE (arg0) == MULT_EXPR && TREE_CODE (arg1) == MULT_EXPR
&& operand_equal_p (TREE_OPERAND (arg0, 1),
TREE_OPERAND (arg1, 1), 0))
/* (A * C) + (B * C) -> (A+B) * C.
We are most concerned about the case where C is a constant,
but other combinations show up during loop reduction. Since
it is not difficult, try all four possibilities. */
arg00 = TREE_OPERAND (arg0, 0);
arg01 = TREE_OPERAND (arg0, 1);
arg10 = TREE_OPERAND (arg1, 0);
arg11 = TREE_OPERAND (arg1, 1);
same = NULL_TREE;
if (operand_equal_p (arg01, arg11, 0))
same = arg01, alt0 = arg00, alt1 = arg10;
else if (operand_equal_p (arg00, arg10, 0))
same = arg00, alt0 = arg01, alt1 = arg11;
else if (operand_equal_p (arg00, arg11, 0))
same = arg00, alt0 = arg01, alt1 = arg10;
else if (operand_equal_p (arg01, arg10, 0))
same = arg01, alt0 = arg00, alt1 = arg11;
if (same)
return fold (build (MULT_EXPR, type,
fold (build (PLUS_EXPR, type,
TREE_OPERAND (arg0, 0),
TREE_OPERAND (arg1, 0))),
TREE_OPERAND (arg0, 1)));
fold (build (PLUS_EXPR, type, alt0, alt1)),
same));
}
}
/* In IEEE floating point, x+0 may not equal x. */
else if ((TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
......
gcc/loop.c
......@@ -272,6 +272,8 @@ struct movable
struct movable *next;
};
static struct movable *the_movables;
FILE *loop_dump_stream;
/* Forward declarations. */
......@@ -310,16 +312,12 @@ static void record_giv PROTO((struct induction *, rtx, rtx, rtx, rtx, rtx, int,
static void update_giv_derive PROTO((rtx));
static int basic_induction_var PROTO((rtx, enum machine_mode, rtx, rtx, rtx *, rtx *));
static rtx simplify_giv_expr PROTO((rtx, int *));
static int general_induction_var PROTO((rtx, rtx *, rtx *, rtx *));
static int general_induction_var PROTO((rtx, rtx *, rtx *, rtx *, int, int *));
static int consec_sets_giv PROTO((int, rtx, rtx, rtx, rtx *, rtx *));
static int check_dbra_loop PROTO((rtx, int, rtx));
#ifdef ADDRESS_COST
static rtx express_from_1 PROTO((rtx, rtx, rtx));
static rtx express_from PROTO((struct induction *, struct induction *));
#endif
static int combine_givs_p PROTO((struct induction *, struct induction *));
#ifdef GIV_SORT_CRITERION
static int giv_sort PROTO((struct induction **, struct induction **));
#endif
static rtx combine_givs_p PROTO((struct induction *, struct induction *));
static void combine_givs PROTO((struct iv_class *));
static int product_cheap_p PROTO((rtx, rtx));
static int maybe_eliminate_biv PROTO((struct iv_class *, rtx, rtx, int, int, int));
......@@ -349,15 +347,19 @@ static int indirect_jump_in_function_p PROTO((rtx));
/* Relative gain of eliminating various kinds of operations. */
int add_cost;
static int add_cost;
#if 0
int shift_cost;
int mult_cost;
static int shift_cost;
static int mult_cost;
#endif
/* Benefit penalty, if a giv is not replaceable, i.e. must emit an insn to
copy the value of the strength reduced giv to its original register. */
int copy_cost;
static int copy_cost;
/* Cost of using a register, to normalize the benefits of a giv. */
static int reg_address_cost;
void
init_loop ()
......@@ -367,6 +369,12 @@ init_loop ()
add_cost = rtx_cost (gen_rtx_PLUS (word_mode, reg, reg), SET);
#ifdef ADDRESS_COST
reg_address_cost = ADDRESS_COST (reg);
#else
reg_address_cost = rtx_cost (reg, MEM);
#endif
/* We multiply by 2 to reconcile the difference in scale between
these two ways of computing costs. Otherwise the cost of a copy
will be far less than the cost of an add. */
......@@ -542,6 +550,8 @@ loop_optimize (f, dumpfile, unroll_p)
to one mapping will remain. */
if (unroll_p && write_symbols != NO_DEBUG)
unroll_block_trees ();
end_alias_analysis ();
}
/* Optimize one loop whose start is LOOP_START and end is END.
......@@ -1084,8 +1094,11 @@ scan_loop (loop_start, end, nregs, unroll_p)
n_times_set[i] = n_times_used[i];
if (flag_strength_reduce)
{
the_movables = movables;
strength_reduce (scan_start, end, loop_top,
insn_count, loop_start, end, unroll_p);
}
}
/* Add elements to *OUTPUT to record all the pseudo-regs
......@@ -3318,7 +3331,7 @@ loop_reg_used_before_p (set, insn, loop_start, scan_start, loop_end)
value is a linear function of a biv. */
/* Bivs are recognized by `basic_induction_var';
Givs by `general_induct_var'. */
Givs by `general_induction_var'. */
/* Indexed by register number, indicates whether or not register is an
induction variable, and if so what type. */
......@@ -3789,14 +3802,13 @@ strength_reduce (scan_start, end, loop_top, insn_count,
continue;
if (/* SET_SRC is a giv. */
((benefit = general_induction_var (SET_SRC (set),
&src_reg, &add_val,
&mult_val))
(general_induction_var (SET_SRC (set), &src_reg, &add_val,
&mult_val, 0, &benefit)
/* Equivalent expression is a giv. */
|| ((regnote = find_reg_note (p, REG_EQUAL, NULL_RTX))
&& (benefit = general_induction_var (XEXP (regnote, 0),
&src_reg,
&add_val, &mult_val))))
&& general_induction_var (XEXP (regnote, 0), &src_reg,
&add_val, &mult_val, 0,
&benefit)))
/* Don't try to handle any regs made by loop optimization.
We have nothing on them in regno_first_uid, etc. */
&& REGNO (dest_reg) < max_reg_before_loop
......@@ -4540,12 +4552,13 @@ find_mem_givs (x, insn, not_every_iteration, loop_start, loop_end)
rtx mult_val;
int benefit;
benefit = general_induction_var (XEXP (x, 0),
&src_reg, &add_val, &mult_val);
/* This code used to disable creating GIVs with mult_val == 1 and
add_val == 0. However, this leads to lost optimizations when
it comes time to combine a set of related DEST_ADDR GIVs, since
this one would not be seen. */
/* Don't make a DEST_ADDR giv with mult_val == 1 && add_val == 0.
Such a giv isn't useful. */
if (benefit > 0 && (mult_val != const1_rtx || add_val != const0_rtx))
if (general_induction_var (XEXP (x, 0), &src_reg, &add_val,
&mult_val, 1, &benefit))
{
/* Found one; record it. */
struct induction *v
......@@ -4858,6 +4871,32 @@ record_giv (v, insn, src_reg, dest_reg, mult_val, add_val, benefit,
}
}
/* Record whether the add_val contains a const_int, for later use by
combine_givs. */
{
rtx tem = add_val;
v->no_const_addval = 1;
if (tem == const0_rtx)
;
else if (GET_CODE (tem) == CONST_INT)
v->no_const_addval = 0;
else if (GET_CODE (tem) == PLUS)
{
while (1)
{
if (GET_CODE (XEXP (tem, 0)) == PLUS)
tem = XEXP (tem, 0);
else if (GET_CODE (XEXP (tem, 1)) == PLUS)
tem = XEXP (tem, 1);
else
break;
}
if (GET_CODE (XEXP (tem, 1)) == CONST_INT)
v->no_const_addval = 0;
}
}
if (loop_dump_stream)
{
if (type == DEST_REG)
......@@ -4875,6 +4914,9 @@ record_giv (v, insn, src_reg, dest_reg, mult_val, add_val, benefit,
if (v->replaceable)
fprintf (loop_dump_stream, " replaceable");
if (v->no_const_addval)
fprintf (loop_dump_stream, " ncav");
if (GET_CODE (mult_val) == CONST_INT)
{
fprintf (loop_dump_stream, " mult ");
......@@ -5197,12 +5239,12 @@ basic_induction_var (x, mode, dest_reg, p, inc_val, mult_val)
switch (code)
{
case PLUS:
if (XEXP (x, 0) == dest_reg
if (rtx_equal_p (XEXP (x, 0), dest_reg)
|| (GET_CODE (XEXP (x, 0)) == SUBREG
&& SUBREG_PROMOTED_VAR_P (XEXP (x, 0))
&& SUBREG_REG (XEXP (x, 0)) == dest_reg))
arg = XEXP (x, 1);
else if (XEXP (x, 1) == dest_reg
else if (rtx_equal_p (XEXP (x, 1), dest_reg)
|| (GET_CODE (XEXP (x, 1)) == SUBREG
&& SUBREG_PROMOTED_VAR_P (XEXP (x, 1))
&& SUBREG_REG (XEXP (x, 1)) == dest_reg))
......@@ -5226,30 +5268,36 @@ basic_induction_var (x, mode, dest_reg, p, inc_val, mult_val)
return 0;
case REG:
/* If this register is assigned in the previous insn, look at its
/* If this register is assigned in a previous insn, look at its
source, but don't go outside the loop or past a label. */
for (insn = PREV_INSN (p);
(insn && GET_CODE (insn) == NOTE
insn = p;
while (1)
{
do {
insn = PREV_INSN (insn);
} while (insn && GET_CODE (insn) == NOTE
&& NOTE_LINE_NUMBER (insn) != NOTE_INSN_LOOP_BEG);
insn = PREV_INSN (insn))
;
if (insn)
if (!insn)
break;
set = single_set (insn);
if (set == 0)
break;
if (set != 0
&& (SET_DEST (set) == x
if ((SET_DEST (set) == x
|| (GET_CODE (SET_DEST (set)) == SUBREG
&& (GET_MODE_SIZE (GET_MODE (SET_DEST (set)))
<= UNITS_PER_WORD)
&& SUBREG_REG (SET_DEST (set)) == x)))
return basic_induction_var (SET_SRC (set),
&& SUBREG_REG (SET_DEST (set)) == x))
&& basic_induction_var (SET_SRC (set),
(GET_MODE (SET_SRC (set)) == VOIDmode
? GET_MODE (x)
: GET_MODE (SET_SRC (set))),
dest_reg, insn,
inc_val, mult_val);
inc_val, mult_val))
return 1;
}
/* ... fall through ... */
/* Can accept constant setting of biv only when inside inner most loop.
......@@ -5280,6 +5328,7 @@ basic_induction_var (x, mode, dest_reg, p, inc_val, mult_val)
case SIGN_EXTEND:
return basic_induction_var (XEXP (x, 0), GET_MODE (XEXP (x, 0)),
dest_reg, p, inc_val, mult_val);
case ASHIFTRT:
/* Similar, since this can be a sign extension. */
for (insn = PREV_INSN (p);
......@@ -5321,14 +5370,15 @@ basic_induction_var (x, mode, dest_reg, p, inc_val, mult_val)
such that the value of X is biv * mult + add; */
static int
general_induction_var (x, src_reg, add_val, mult_val)
general_induction_var (x, src_reg, add_val, mult_val, is_addr, pbenefit)
rtx x;
rtx *src_reg;
rtx *add_val;
rtx *mult_val;
int is_addr;
int *pbenefit;
{
rtx orig_x = x;
int benefit = 0;
char *storage;
/* If this is an invariant, forget it, it isn't a giv. */
......@@ -5338,7 +5388,8 @@ general_induction_var (x, src_reg, add_val, mult_val)
/* See if the expression could be a giv and get its form.
Mark our place on the obstack in case we don't find a giv. */
storage = (char *) oballoc (0);
x = simplify_giv_expr (x, &benefit);
*pbenefit = 0;
x = simplify_giv_expr (x, pbenefit);
if (x == 0)
{
obfree (storage);
......@@ -5398,12 +5449,21 @@ general_induction_var (x, src_reg, add_val, mult_val)
if (GET_CODE (*mult_val) == USE)
*mult_val = XEXP (*mult_val, 0);
benefit += rtx_cost (orig_x, SET);
if (is_addr)
{
#ifdef ADDRESS_COST
*pbenefit += ADDRESS_COST (orig_x) - reg_address_cost;
#else
*pbenefit += rtx_cost (orig_x, MEM) - reg_address_cost;
#endif
}
else
*pbenefit += rtx_cost (orig_x, SET);
/* Always return some benefit if this is a giv so it will be detected
as such. This allows elimination of bivs that might otherwise
not be eliminated. */
return benefit == 0 ? 1 : benefit;
/* Always return true if this is a giv so it will be detected as such,
even if the benefit is zero or negative. This allows elimination
of bivs that might otherwise not be eliminated. */
return 1;
}
/* Given an expression, X, try to form it as a linear function of a biv.
......@@ -5426,6 +5486,9 @@ general_induction_var (x, src_reg, add_val, mult_val)
*BENEFIT will be incremented by the benefit of any sub-giv encountered. */
static rtx sge_plus PROTO ((enum machine_mode, rtx, rtx));
static rtx sge_plus_constant PROTO ((rtx, rtx));
static rtx
simplify_giv_expr (x, benefit)
rtx x;
......@@ -5440,7 +5503,7 @@ simplify_giv_expr (x, benefit)
if (mode != VOIDmode
&& (GET_MODE_CLASS (mode) != MODE_INT
|| GET_MODE_BITSIZE (mode) > HOST_BITS_PER_WIDE_INT))
return 0;
return NULL_RTX;
switch (GET_CODE (x))
{
......@@ -5448,12 +5511,14 @@ simplify_giv_expr (x, benefit)
arg0 = simplify_giv_expr (XEXP (x, 0), benefit);
arg1 = simplify_giv_expr (XEXP (x, 1), benefit);
if (arg0 == 0 || arg1 == 0)
return 0;
return NULL_RTX;
/* Put constant last, CONST_INT last if both constant. */
if ((GET_CODE (arg0) == USE
|| GET_CODE (arg0) == CONST_INT)
&& GET_CODE (arg1) != CONST_INT)
&& ! ((GET_CODE (arg0) == USE
&& GET_CODE (arg1) == USE)
|| GET_CODE (arg1) == CONST_INT))
tem = arg0, arg0 = arg1, arg1 = tem;
/* Handle addition of zero, then addition of an invariant. */
......@@ -5464,29 +5529,22 @@ simplify_giv_expr (x, benefit)
{
case CONST_INT:
case USE:
/* Both invariant. Only valid if sum is machine operand.
First strip off possible USE on the operands. */
/* Adding two invariants must result in an invariant, so enclose
addition operation inside a USE and return it. */
if (GET_CODE (arg0) == USE)
arg0 = XEXP (arg0, 0);
if (GET_CODE (arg1) == USE)
arg1 = XEXP (arg1, 0);
tem = 0;
if (CONSTANT_P (arg0) && GET_CODE (arg1) == CONST_INT)
{
tem = plus_constant (arg0, INTVAL (arg1));
if (GET_CODE (tem) != CONST_INT)
tem = gen_rtx_USE (mode, tem);
}
if (GET_CODE (arg0) == CONST_INT)
tem = arg0, arg0 = arg1, arg1 = tem;
if (GET_CODE (arg1) == CONST_INT)
tem = sge_plus_constant (arg0, arg1);
else
{
/* Adding two invariants must result in an invariant,
so enclose addition operation inside a USE and
return it. */
tem = gen_rtx_USE (mode, gen_rtx_PLUS (mode, arg0, arg1));
}
tem = sge_plus (mode, arg0, arg1);
if (GET_CODE (tem) != CONST_INT)
tem = gen_rtx_USE (mode, tem);
return tem;
case REG:
......@@ -5496,10 +5554,9 @@ simplify_giv_expr (x, benefit)
case PLUS:
/* (a + invar_1) + invar_2. Associate. */
return simplify_giv_expr (gen_rtx_PLUS (mode,
XEXP (arg0, 0),
gen_rtx_PLUS (mode,
XEXP (arg0, 1), arg1)),
return simplify_giv_expr (
gen_rtx_PLUS (mode, XEXP (arg0, 0),
gen_rtx_PLUS (mode, XEXP (arg0, 1), arg1)),
benefit);
default:
......@@ -5528,10 +5585,10 @@ simplify_giv_expr (x, benefit)
/* Now must have MULT + MULT. Distribute if same biv, else not giv. */
if (GET_CODE (arg0) != MULT || GET_CODE (arg1) != MULT)
abort ();
return NULL_RTX;
if (XEXP (arg0, 0) != XEXP (arg1, 0))
return 0;
if (!rtx_equal_p (arg0, arg1))
return NULL_RTX;
return simplify_giv_expr (gen_rtx_MULT (mode,
XEXP (arg0, 0),
......@@ -5552,7 +5609,7 @@ simplify_giv_expr (x, benefit)
arg0 = simplify_giv_expr (XEXP (x, 0), benefit);
arg1 = simplify_giv_expr (XEXP (x, 1), benefit);
if (arg0 == 0 || arg1 == 0)
return 0;
return NULL_RTX;
/* Put constant last, CONST_INT last if both constant. */
if ((GET_CODE (arg0) == USE || GET_CODE (arg0) == CONST_INT)
......@@ -5561,7 +5618,7 @@ simplify_giv_expr (x, benefit)
/* If second argument is not now constant, not giv. */
if (GET_CODE (arg1) != USE && GET_CODE (arg1) != CONST_INT)
return 0;
return NULL_RTX;
/* Handle multiply by 0 or 1. */
if (arg1 == const0_rtx)
......@@ -5581,8 +5638,25 @@ simplify_giv_expr (x, benefit)
return GEN_INT (INTVAL (arg0) * INTVAL (arg1));
case USE:
/* invar * invar. Not giv. */
return 0;
/* invar * invar. It is a giv, but very few of these will
actually pay off, so limit to simple registers. */
if (GET_CODE (arg1) != CONST_INT)
return NULL_RTX;
arg0 = XEXP (arg0, 0);
if (GET_CODE (arg0) == REG)
tem = gen_rtx_MULT (mode, arg0, arg1);
else if (GET_CODE (arg0) == MULT
&& GET_CODE (XEXP (arg0, 0)) == REG
&& GET_CODE (XEXP (arg0, 1)) == CONST_INT)
{
tem = gen_rtx_MULT (mode, XEXP (arg0, 0),
GEN_INT (INTVAL (XEXP (arg0, 1))
* INTVAL (arg1)));
}
else
return NULL_RTX;
return gen_rtx_USE (mode, tem);
case MULT:
/* (a * invar_1) * invar_2. Associate. */
......@@ -5663,6 +5737,72 @@ simplify_giv_expr (x, benefit)
}
default:
/* If it isn't an induction variable, and it is invariant, we
may be able to simplify things further by looking through
the bits we just moved outside the loop. */
if (invariant_p (x) == 1)
{
struct movable *m;
for (m = the_movables; m ; m = m->next)
if (rtx_equal_p (x, m->set_dest))
{
/* Ok, we found a match. Substitute and simplify. */
/* If we match another movable, we must use that, as
this one is going away. */
if (m->match)
return simplify_giv_expr (m->match->set_dest, benefit);
/* If consec is non-zero, this is a member of a group of
instructions that were moved together. We handle this
case only to the point of seeking to the last insn and
looking for a REG_EQUAL. Fail if we don't find one. */
if (m->consec != 0)
{
int i = m->consec;
tem = m->insn;
do { tem = NEXT_INSN (tem); } while (--i > 0);
tem = find_reg_note (tem, REG_EQUAL, NULL_RTX);
if (tem)
tem = XEXP (tem, 0);
}
else
{
tem = single_set (m->insn);
if (tem)
tem = SET_SRC (tem);
}
if (tem)
{
/* What we are most interested in is pointer
arithmetic on invariants -- only take
patterns we may be able to do something with. */
if (GET_CODE (tem) == PLUS
|| GET_CODE (tem) == MULT
|| GET_CODE (tem) == ASHIFT
|| GET_CODE (tem) == CONST_INT
|| GET_CODE (tem) == SYMBOL_REF)
{
tem = simplify_giv_expr (tem, benefit);
if (tem)
return tem;
}
else if (GET_CODE (tem) == CONST
&& GET_CODE (XEXP (tem, 0)) == PLUS
&& GET_CODE (XEXP (XEXP (tem, 0), 0)) == SYMBOL_REF
&& GET_CODE (XEXP (XEXP (tem, 0), 1)) == CONST_INT)
{
tem = simplify_giv_expr (XEXP (tem, 0), benefit);
if (tem)
return tem;
}
}
break;
}
}
break;
}
......@@ -5677,7 +5817,11 @@ simplify_giv_expr (x, benefit)
{
if (GET_CODE (x) == CONST_INT)
return x;
else
if (GET_CODE (x) == CONST
&& GET_CODE (XEXP (x, 0)) == PLUS
&& GET_CODE (XEXP (XEXP (x, 0), 0)) == SYMBOL_REF
&& GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT)
x = XEXP (x, 0);
return gen_rtx_USE (mode, x);
}
else
......@@ -5685,6 +5829,56 @@ simplify_giv_expr (x, benefit)
}
}
/* This routine folds invariants such that there is only ever one
CONST_INT in the summation. It is only used by simplify_giv_expr. */
static rtx
sge_plus_constant (x, c)
rtx x, c;
{
if (GET_CODE (x) == CONST_INT)
return GEN_INT (INTVAL (x) + INTVAL (c));
else if (GET_CODE (x) != PLUS)
return gen_rtx_PLUS (GET_MODE (x), x, c);
else if (GET_CODE (XEXP (x, 1)) == CONST_INT)
{
return gen_rtx_PLUS (GET_MODE (x), XEXP (x, 0),
GEN_INT (INTVAL (XEXP (x, 1)) + INTVAL (c)));
}
else if (GET_CODE (XEXP (x, 0)) == PLUS
|| GET_CODE (XEXP (x, 1)) != PLUS)
{
return gen_rtx_PLUS (GET_MODE (x),
sge_plus_constant (XEXP (x, 0), c), XEXP (x, 1));
}
else
{
return gen_rtx_PLUS (GET_MODE (x),
sge_plus_constant (XEXP (x, 1), c), XEXP (x, 0));
}
}
static rtx
sge_plus (mode, x, y)
enum machine_mode mode;
rtx x, y;
{
while (GET_CODE (y) == PLUS)
{
rtx a = XEXP (y, 0);
if (GET_CODE (a) == CONST_INT)
x = sge_plus_constant (x, a);
else
x = gen_rtx_PLUS (mode, x, a);
y = XEXP (y, 1);
}
if (GET_CODE (y) == CONST_INT)
x = sge_plus_constant (x, y);
else
x = gen_rtx_PLUS (mode, x, y);
return x;
}
/* Help detect a giv that is calculated by several consecutive insns;
for example,
giv = biv * M
......@@ -5754,12 +5948,12 @@ consec_sets_giv (first_benefit, p, src_reg, dest_reg,
&& (set = single_set (p))
&& GET_CODE (SET_DEST (set)) == REG
&& SET_DEST (set) == dest_reg
&& ((benefit = general_induction_var (SET_SRC (set), &src_reg,
add_val, mult_val))
&& (general_induction_var (SET_SRC (set), &src_reg,
add_val, mult_val, 0, &benefit)
/* Giv created by equivalent expression. */
|| ((temp = find_reg_note (p, REG_EQUAL, NULL_RTX))
&& (benefit = general_induction_var (XEXP (temp, 0), &src_reg,
add_val, mult_val))))
&& general_induction_var (XEXP (temp, 0), &src_reg,
add_val, mult_val, 0, &benefit)))
&& src_reg == v->src_reg)
{
if (find_reg_note (p, REG_RETVAL, NULL_RTX))
......@@ -5794,13 +5988,110 @@ consec_sets_giv (first_benefit, p, src_reg, dest_reg,
it cannot possibly be a valid address, 0 is returned.
To perform the computation, we note that
G1 = a * v + b and
G2 = c * v + d
G1 = x * v + a and
G2 = y * v + b
where `v' is the biv.
So G2 = (c/a) * G1 + (d - b*c/a) */
So G2 = (y/b) * G1 + (b - a*y/x).
Note that MULT = y/x.
Update: A and B are now allowed to be additive expressions such that
B contains all variables in A. That is, computing B-A will not require
subtracting variables. */
static rtx
express_from_1 (a, b, mult)
rtx a, b, mult;
{
/* If MULT is zero, then A*MULT is zero, and our expression is B. */
if (mult == const0_rtx)
return b;
/* If MULT is not 1, we cannot handle A with non-constants, since we
would then be required to subtract multiples of the registers in A.
This is theoretically possible, and may even apply to some Fortran
constructs, but it is a lot of work and we do not attempt it here. */
if (mult != const1_rtx && GET_CODE (a) != CONST_INT)
return NULL_RTX;
/* In general these structures are sorted top to bottom (down the PLUS
chain), but not left to right across the PLUS. If B is a higher
order giv than A, we can strip one level and recurse. If A is higher
order, we'll eventually bail out, but won't know that until the end.
If they are the same, we'll strip one level around this loop. */
while (GET_CODE (a) == PLUS && GET_CODE (b) == PLUS)
{
rtx ra, rb, oa, ob, tmp;
ra = XEXP (a, 0), oa = XEXP (a, 1);
if (GET_CODE (ra) == PLUS)
tmp = ra, ra = oa, oa = tmp;
rb = XEXP (b, 0), ob = XEXP (b, 1);
if (GET_CODE (rb) == PLUS)
tmp = rb, rb = ob, ob = tmp;
if (rtx_equal_p (ra, rb))
/* We matched: remove one reg completely. */
a = oa, b = ob;
else if (GET_CODE (ob) != PLUS && rtx_equal_p (ra, ob))
/* An alternate match. */
a = oa, b = rb;
else if (GET_CODE (oa) != PLUS && rtx_equal_p (oa, rb))
/* An alternate match. */
a = ra, b = ob;
else
{
/* Indicates an extra register in B. Strip one level from B and
recurse, hoping B was the higher order expression. */
ob = express_from_1 (a, ob, mult);
if (ob == NULL_RTX)
return NULL_RTX;
return gen_rtx_PLUS (GET_MODE (b), rb, ob);
}
}
/* Here we are at the last level of A, go through the cases hoping to
get rid of everything but a constant. */
if (GET_CODE (a) == PLUS)
{
rtx ra, oa, tmp;
ra = XEXP (a, 0), oa = XEXP (a, 1);
if (rtx_equal_p (oa, b))
oa = ra;
else if (!rtx_equal_p (ra, b))
return NULL_RTX;
if (GET_CODE (oa) != CONST_INT)
return NULL_RTX;
return GEN_INT (-INTVAL (oa) * INTVAL (mult));
}
else if (GET_CODE (a) == CONST_INT)
{
return plus_constant (b, -INTVAL (a) * INTVAL (mult));
}
else if (GET_CODE (b) == PLUS)
{
if (rtx_equal_p (a, XEXP (b, 0)))
return XEXP (b, 1);
else if (rtx_equal_p (a, XEXP (b, 1)))
return XEXP (b, 0);
else
return NULL_RTX;
}
else if (rtx_equal_p (a, b))
return const0_rtx;
return NULL_RTX;
}
#ifdef ADDRESS_COST
static rtx
express_from (g1, g2)
struct induction *g1, *g2;
......@@ -5810,15 +6101,25 @@ express_from (g1, g2)
/* The value that G1 will be multiplied by must be a constant integer. Also,
the only chance we have of getting a valid address is if b*c/a (see above
for notation) is also an integer. */
if (GET_CODE (g1->mult_val) != CONST_INT
|| GET_CODE (g2->mult_val) != CONST_INT
|| GET_CODE (g1->add_val) != CONST_INT
|| g1->mult_val == const0_rtx
if (GET_CODE (g1->mult_val) == CONST_INT
&& GET_CODE (g2->mult_val) == CONST_INT)
{
if (g1->mult_val == const0_rtx
|| INTVAL (g2->mult_val) % INTVAL (g1->mult_val) != 0)
return 0;
return NULL_RTX;
mult = GEN_INT (INTVAL (g2->mult_val) / INTVAL (g1->mult_val));
add = plus_constant (g2->add_val, - INTVAL (g1->add_val) * INTVAL (mult));
}
else if (rtx_equal_p (g1->mult_val, g2->mult_val))
mult = const1_rtx;
else
{
/* ??? Find out if the one is a multiple of the other? */
return NULL_RTX;
}
add = express_from_1 (g1->add_val, g2->add_val, mult);
if (add == NULL_RTX)
return NULL_RTX;
/* Form simplified final result. */
if (mult == const0_rtx)
......@@ -5833,59 +6134,101 @@ express_from (g1, g2)
else
return gen_rtx_PLUS (g2->mode, mult, add);
}
#endif
/* Return 1 if giv G2 can be combined with G1. This means that G2 can use
(either directly or via an address expression) a register used to represent
G1. Set g2->new_reg to a represtation of G1 (normally just
g1->dest_reg). */
static int
static rtx
combine_givs_p (g1, g2)
struct induction *g1, *g2;
{
#ifdef ADDRESS_COST
rtx tem;
#endif
rtx tem = express_from (g1, g2);
/* If these givs are identical, they can be combined. */
if (rtx_equal_p (g1->mult_val, g2->mult_val)
&& rtx_equal_p (g1->add_val, g2->add_val))
/* If these givs are identical, they can be combined. We use the results
of express_from because the addends are not in a canonical form, so
rtx_equal_p is a weaker test. */
if (tem == const0_rtx)
{
g2->new_reg = g1->dest_reg;
return 1;
return g1->dest_reg;
}
#ifdef ADDRESS_COST
/* If G2 can be expressed as a function of G1 and that function is valid
as an address and no more expensive than using a register for G2,
the expression of G2 in terms of G1 can be used. */
if (g2->giv_type == DEST_ADDR
&& (tem = express_from (g1, g2)) != 0
if (tem != NULL_RTX
&& g2->giv_type == DEST_ADDR
&& memory_address_p (g2->mem_mode, tem)
&& ADDRESS_COST (tem) <= ADDRESS_COST (*g2->location))
/* ??? Looses, especially with -fforce-addr, where *g2->location
will always be a register, and so anything more complicated
gets discarded. */
#if 0
#ifdef ADDRESS_COST
&& ADDRESS_COST (tem) <= ADDRESS_COST (*g2->location)
#else
&& rtx_cost (tem, MEM) <= rtx_cost (*g2->location, MEM)
#endif
#endif
)
{
g2->new_reg = tem;
return 1;
return tem;
}
#endif
return 0;
return NULL_RTX;
}
struct combine_givs_stats
{
int giv_number;
int total_benefit;
};
static int
cmp_combine_givs_stats (x, y)
struct combine_givs_stats *x, *y;
{
int d;
d = y->total_benefit - x->total_benefit;
/* Stabilize the sort. */
if (!d)
d = x->giv_number - y->giv_number;
return d;
}
#ifdef GIV_SORT_CRITERION
/* Compare two givs and sort the most desirable one for combinations first.
This is used only in one qsort call below. */
/* If one of these givs is a DEST_REG that was only used once, by the
other giv, this is actually a single use. Return 0 if this is not
the case, -1 if g1 is the DEST_REG involved, and 1 if it was g2. */
static int
giv_sort (x, y)
struct induction **x, **y;
combine_givs_used_once (g1, g2)
struct induction *g1, *g2;
{
GIV_SORT_CRITERION (*x, *y);
if (g1->giv_type == DEST_REG
&& n_times_used[REGNO (g1->dest_reg)] == 1
&& reg_mentioned_p (g1->dest_reg, PATTERN (g2->insn)))
return -1;
if (g2->giv_type == DEST_REG
&& n_times_used[REGNO (g2->dest_reg)] == 1
&& reg_mentioned_p (g2->dest_reg, PATTERN (g1->insn)))
return 1;
return 0;
}
#endif
static int
combine_givs_benefit_from (g1, g2)
struct induction *g1, *g2;
{
int tmp = combine_givs_used_once (g1, g2);
if (tmp < 0)
return 0;
else if (tmp > 0)
return g2->benefit - g1->benefit;
else
return g2->benefit;
}
/* Check all pairs of givs for iv_class BL and see if any can be combined with
any other. If so, point SAME to the giv combined with and set NEW_REG to
......@@ -5897,80 +6240,155 @@ combine_givs (bl)
struct iv_class *bl;
{
struct induction *g1, *g2, **giv_array;
int i, j, giv_count, pass;
int i, j, k, giv_count;
struct combine_givs_stats *stats;
rtx *can_combine;
/* Count givs, because bl->giv_count is incorrect here. */
giv_count = 0;
for (g1 = bl->giv; g1; g1 = g1->next_iv)
if (!g1->ignore)
giv_count++;
giv_array
= (struct induction **) alloca (giv_count * sizeof (struct induction *));
i = 0;
for (g1 = bl->giv; g1; g1 = g1->next_iv)
if (!g1->ignore)
giv_array[i++] = g1;
#ifdef GIV_SORT_CRITERION
/* Sort the givs if GIV_SORT_CRITERION is defined.
This is usually defined for processors which lack
negative register offsets so more givs may be combined. */
if (loop_dump_stream)
fprintf (loop_dump_stream, "%d givs counted, sorting...\n", giv_count);
stats = (struct combine_givs_stats *) alloca (giv_count * sizeof (*stats));
bzero (stats, giv_count * sizeof (*stats));
qsort (giv_array, giv_count, sizeof (struct induction *), giv_sort);
#endif
can_combine = (rtx *) alloca (giv_count * giv_count * sizeof(rtx));
bzero (can_combine, giv_count * giv_count * sizeof(rtx));
for (i = 0; i < giv_count; i++)
{
int this_benefit;
g1 = giv_array[i];
for (pass = 0; pass <= 1; pass++)
this_benefit = g1->benefit;
/* Add an additional weight for zero addends. */
if (g1->no_const_addval)
this_benefit += 1;
for (j = 0; j < giv_count; j++)
{
rtx this_combine;
g2 = giv_array[j];
if (g1 != g2
/* First try to combine with replaceable givs, then all givs. */
&& (g1->replaceable || pass == 1)
/* If either has already been combined or is to be ignored, can't
combine. */
&& ! g1->ignore && ! g2->ignore && ! g1->same && ! g2->same
/* If something has been based on G2, G2 cannot itself be based
on something else. */
&& ! g2->combined_with
&& combine_givs_p (g1, g2))
{
/* g2->new_reg set by `combine_givs_p' */
g2->same = g1;
g1->combined_with = 1;
&& (this_combine = combine_givs_p (g1, g2)) != NULL_RTX)
{
can_combine[i*giv_count + j] = this_combine;
this_benefit += combine_givs_benefit_from (g1, g2);
/* Add an additional weight for being reused more times. */
this_benefit += 3;
}
}
stats[i].giv_number = i;
stats[i].total_benefit = this_benefit;
}
/* If one of these givs is a DEST_REG that was only used
once, by the other giv, this is actually a single use.
The DEST_REG has the correct cost, while the other giv
counts the REG use too often. */
if (g2->giv_type == DEST_REG
&& n_times_used[REGNO (g2->dest_reg)] == 1
&& reg_mentioned_p (g2->dest_reg, PATTERN (g1->insn)))
g1->benefit = g2->benefit;
else if (g1->giv_type != DEST_REG
|| n_times_used[REGNO (g1->dest_reg)] != 1
|| ! reg_mentioned_p (g1->dest_reg,
PATTERN (g2->insn)))
/* Iterate, combining until we can't. */
restart:
qsort (stats, giv_count, sizeof(*stats), cmp_combine_givs_stats);
if (loop_dump_stream)
{
g1->benefit += g2->benefit;
g1->times_used += g2->times_used;
fprintf (loop_dump_stream, "Sorted combine statistics:\n");
for (k = 0; k < giv_count; k++)
{
g1 = giv_array[stats[k].giv_number];
if (!g1->combined_with && !g1->same)
fprintf (loop_dump_stream, " {%d, %d}",
INSN_UID (giv_array[stats[k].giv_number]->insn),
stats[k].total_benefit);
}
putc ('\n', loop_dump_stream);
}
for (k = 0; k < giv_count; k++)
{
int g1_add_benefit = 0;
i = stats[k].giv_number;
g1 = giv_array[i];
/* If it has already been combined, skip. */
if (g1->combined_with || g1->same)
continue;
for (j = 0; j < giv_count; j++)
{
g2 = giv_array[j];
if (g1 != g2 && can_combine[i*giv_count + j]
/* If it has already been combined, skip. */
&& ! g2->same && ! g2->combined_with)
{
int l;
g2->new_reg = can_combine[i*giv_count + j];
g2->same = g1;
g1->combined_with = 1;
if (!combine_givs_used_once (g1, g2))
g1->times_used += 1;
g1->lifetime += g2->lifetime;
g1_add_benefit += combine_givs_benefit_from (g1, g2);
/* ??? The new final_[bg]iv_value code does a much better job
of finding replaceable giv's, and hence this code may no
longer be necessary. */
if (! g2->replaceable && REG_USERVAR_P (g2->dest_reg))
g1->benefit -= copy_cost;
g1->lifetime += g2->lifetime;
g1_add_benefit -= copy_cost;
/* To help optimize the next set of combinations, remove
this giv from the benefits of other potential mates. */
for (l = 0; l < giv_count; ++l)
{
int m = stats[l].giv_number;
if (can_combine[m*giv_count + j])
{
/* Remove additional weight for being reused. */
stats[l].total_benefit -= 3 +
combine_givs_benefit_from (giv_array[m], g2);
}
}
if (loop_dump_stream)
fprintf (loop_dump_stream, "giv at %d combined with giv at %d\n",
fprintf (loop_dump_stream,
"giv at %d combined with giv at %d\n",
INSN_UID (g2->insn), INSN_UID (g1->insn));
}
}
/* To help optimize the next set of combinations, remove
this giv from the benefits of other potential mates. */
if (g1->combined_with)
{
for (j = 0; j < giv_count; ++j)
{
int m = stats[j].giv_number;
if (can_combine[m*giv_count + j])
{
/* Remove additional weight for being reused. */
stats[j].total_benefit -= 3 +
combine_givs_benefit_from (giv_array[m], g1);
}
}
g1->benefit += g1_add_benefit;
/* We've finished with this giv, and everything it touched.
Restart the combination so that proper weights for the
rest of the givs are properly taken into account. */
/* ??? Ideally we would compact the arrays at this point, so
as to not cover old ground. But sanely compacting
can_combine is tricky. */
goto restart;
}
}
}
......@@ -7262,8 +7680,8 @@ get_condition_for_loop (x)
loop_comparison_code[loop_num] */
#ifdef HAVE_decrement_and_branch_on_count
static
void analyze_loop_iterations (loop_start, loop_end)
static void
analyze_loop_iterations (loop_start, loop_end)
rtx loop_start, loop_end;
{
rtx comparison, comparison_value;
......
gcc/loop.h
......@@ -95,6 +95,7 @@ struct induction
unsigned unrolled : 1; /* 1 if new register has been allocated and
initialized in unrolled loop. */
unsigned shared : 1;
unsigned no_const_addval : 1; /* 1 if add_val does not contain a const. */
int lifetime; /* Length of life of this giv */
int times_used; /* # times this giv is used. */
rtx derive_adjustment; /* If nonzero, is an adjustment to be
......
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