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Commit 4f82319d by Chung-Lin Tang Committed by Chung-Lin Tang
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combine.c (simplify_comparison): Abstract out parts into... 

2011-05-08  Chung-Lin Tang  <cltang@codesourcery.com>

	* combine.c (simplify_comparison): Abstract out parts into...
	(simplify_compare_const): ... new function.
	(try_combine): Generalize parallel arithmetic/compare combining
	to call simplify_compare_const() and CANONICALIZE_COMPARE().

From-SVN: r173552
parent 74605a11
Showing with 270 additions and 212 deletions
gcc/ChangeLog
2011-05-08 Chung-Lin Tang <cltang@codesourcery.com>
* combine.c (simplify_comparison): Abstract out parts into...
(simplify_compare_const): ... new function.
(try_combine): Generalize parallel arithmetic/compare combining
to call simplify_compare_const() and CANONICALIZE_COMPARE().
2011-05-08 Jan Hubicka <jh@suse.cz> 2011-05-08 Jan Hubicka <jh@suse.cz>
* cgraph.c (cgraph_clone_node): Add call_duplication_hook parameter. * cgraph.c (cgraph_clone_node): Add call_duplication_hook parameter.
......
gcc/combine.c
...@@ -450,6 +450,7 @@ static rtx simplify_shift_const (rtx, enum rtx_code, enum machine_mode, rtx, ...@@ -450,6 +450,7 @@ static rtx simplify_shift_const (rtx, enum rtx_code, enum machine_mode, rtx,
int); int);
static int recog_for_combine (rtx *, rtx, rtx *); static int recog_for_combine (rtx *, rtx, rtx *);
static rtx gen_lowpart_for_combine (enum machine_mode, rtx); static rtx gen_lowpart_for_combine (enum machine_mode, rtx);
static enum rtx_code simplify_compare_const (enum rtx_code, rtx, rtx *);
static enum rtx_code simplify_comparison (enum rtx_code, rtx *, rtx *); static enum rtx_code simplify_comparison (enum rtx_code, rtx *, rtx *);
static void update_table_tick (rtx); static void update_table_tick (rtx);
static void record_value_for_reg (rtx, rtx, rtx); static void record_value_for_reg (rtx, rtx, rtx);
...@@ -3046,58 +3047,98 @@ try_combine (rtx i3, rtx i2, rtx i1, rtx i0, int *new_direct_jump_p, ...@@ -3046,58 +3047,98 @@ try_combine (rtx i3, rtx i2, rtx i1, rtx i0, int *new_direct_jump_p,
if (i1 == 0 && added_sets_2 && GET_CODE (PATTERN (i3)) == SET if (i1 == 0 && added_sets_2 && GET_CODE (PATTERN (i3)) == SET
&& GET_CODE (SET_SRC (PATTERN (i3))) == COMPARE && GET_CODE (SET_SRC (PATTERN (i3))) == COMPARE
&& XEXP (SET_SRC (PATTERN (i3)), 1) == const0_rtx && CONST_INT_P (XEXP (SET_SRC (PATTERN (i3)), 1))
&& rtx_equal_p (XEXP (SET_SRC (PATTERN (i3)), 0), i2dest)) && rtx_equal_p (XEXP (SET_SRC (PATTERN (i3)), 0), i2dest))
{ {
#ifdef SELECT_CC_MODE rtx newpat_dest;
rtx *cc_use; rtx *cc_use_loc = NULL, cc_use_insn = NULL_RTX;
enum machine_mode compare_mode; rtx op0 = i2src, op1 = XEXP (SET_SRC (PATTERN (i3)), 1);
#endif enum machine_mode compare_mode, orig_compare_mode;
enum rtx_code compare_code = UNKNOWN, orig_compare_code = UNKNOWN;
newpat = PATTERN (i3); newpat = PATTERN (i3);
SUBST (XEXP (SET_SRC (newpat), 0), i2src); newpat_dest = SET_DEST (newpat);
compare_mode = orig_compare_mode = GET_MODE (newpat_dest);
i2_is_used = 1;
#ifdef SELECT_CC_MODE
/* See if a COMPARE with the operand we substituted in should be done
with the mode that is currently being used. If not, do the same
processing we do in `subst' for a SET; namely, if the destination
is used only once, try to replace it with a register of the proper
mode and also replace the COMPARE. */
if (undobuf.other_insn == 0 if (undobuf.other_insn == 0
&& (cc_use = find_single_use (SET_DEST (newpat), i3, && (cc_use_loc = find_single_use (SET_DEST (newpat), i3,
&undobuf.other_insn)) &cc_use_insn)))
&& ((compare_mode = SELECT_CC_MODE (GET_CODE (*cc_use),
i2src, const0_rtx))
!= GET_MODE (SET_DEST (newpat))))
{ {
if (can_change_dest_mode (SET_DEST (newpat), added_sets_2, compare_code = orig_compare_code = GET_CODE (*cc_use_loc);
compare_mode)) compare_code = simplify_compare_const (compare_code,
{ op0, &op1);
unsigned int regno = REGNO (SET_DEST (newpat)); #ifdef CANONICALIZE_COMPARISON
rtx new_dest; CANONICALIZE_COMPARISON (compare_code, op0, op1);
#endif
}
/* Do the rest only if op1 is const0_rtx, which may be the
result of simplification. */
if (op1 == const0_rtx)
{
/* If a single use of the CC is found, prepare to modify it
when SELECT_CC_MODE returns a new CC-class mode, or when
the above simplify_compare_const() returned a new comparison
operator. undobuf.other_insn is assigned the CC use insn
when modifying it. */
if (cc_use_loc)
{
#ifdef SELECT_CC_MODE
enum machine_mode new_mode
= SELECT_CC_MODE (compare_code, op0, op1);
if (new_mode != orig_compare_mode
&& can_change_dest_mode (SET_DEST (newpat),
added_sets_2, new_mode))
{
unsigned int regno = REGNO (newpat_dest);
compare_mode = new_mode;
if (regno < FIRST_PSEUDO_REGISTER) if (regno < FIRST_PSEUDO_REGISTER)
new_dest = gen_rtx_REG (compare_mode, regno); newpat_dest = gen_rtx_REG (compare_mode, regno);
else else
{ {
SUBST_MODE (regno_reg_rtx[regno], compare_mode); SUBST_MODE (regno_reg_rtx[regno], compare_mode);
new_dest = regno_reg_rtx[regno]; newpat_dest = regno_reg_rtx[regno];
}
}
#endif
/* Cases for modifying the CC-using comparison. */
if (compare_code != orig_compare_code
/* ??? Do we need to verify the zero rtx? */
&& XEXP (*cc_use_loc, 1) == const0_rtx)
{
/* Replace cc_use_loc with entire new RTX. */
SUBST (*cc_use_loc,
gen_rtx_fmt_ee (compare_code, compare_mode,
newpat_dest, const0_rtx));
undobuf.other_insn = cc_use_insn;
}
else if (compare_mode != orig_compare_mode)
{
/* Just replace the CC reg with a new mode. */
SUBST (XEXP (*cc_use_loc, 0), newpat_dest);
undobuf.other_insn = cc_use_insn;
}
} }
SUBST (SET_DEST (newpat), new_dest); /* Now we modify the current newpat:
SUBST (XEXP (*cc_use, 0), new_dest); First, SET_DEST(newpat) is updated if the CC mode has been
altered. For targets without SELECT_CC_MODE, this should be
optimized away. */
if (compare_mode != orig_compare_mode)
SUBST (SET_DEST (newpat), newpat_dest);
/* This is always done to propagate i2src into newpat. */
SUBST (SET_SRC (newpat), SUBST (SET_SRC (newpat),
gen_rtx_COMPARE (compare_mode, i2src, const0_rtx)); gen_rtx_COMPARE (compare_mode, op0, op1));
} /* Create new version of i2pat if needed; the below PARALLEL
else creation needs this to work correctly. */
undobuf.other_insn = 0; if (! rtx_equal_p (i2src, op0))
i2pat = gen_rtx_SET (VOIDmode, i2dest, op0);
i2_is_used = 1;
} }
#endif
} }
else
#endif #endif
if (i2_is_used == 0)
{ {
/* It is possible that the source of I2 or I1 may be performing /* It is possible that the source of I2 or I1 may be performing
an unneeded operation, such as a ZERO_EXTEND of something an unneeded operation, such as a ZERO_EXTEND of something
...@@ -10811,6 +10852,191 @@ gen_lowpart_for_combine (enum machine_mode omode, rtx x) ...@@ -10811,6 +10852,191 @@ gen_lowpart_for_combine (enum machine_mode omode, rtx x)
return gen_rtx_CLOBBER (omode, const0_rtx); return gen_rtx_CLOBBER (omode, const0_rtx);
} }
/* Try to simplify a comparison between OP0 and a constant OP1,
where CODE is the comparison code that will be tested, into a
(CODE OP0 const0_rtx) form.
The result is a possibly different comparison code to use.
*POP1 may be updated. */
static enum rtx_code
simplify_compare_const (enum rtx_code code, rtx op0, rtx *pop1)
{
enum machine_mode mode = GET_MODE (op0);
unsigned int mode_width = GET_MODE_BITSIZE (mode);
HOST_WIDE_INT const_op = INTVAL (*pop1);
/* Get the constant we are comparing against and turn off all bits
not on in our mode. */
if (mode != VOIDmode)
const_op = trunc_int_for_mode (const_op, mode);
/* If we are comparing against a constant power of two and the value
being compared can only have that single bit nonzero (e.g., it was
`and'ed with that bit), we can replace this with a comparison
with zero. */
if (const_op
&& (code == EQ || code == NE || code == GE || code == GEU
|| code == LT || code == LTU)
&& mode_width <= HOST_BITS_PER_WIDE_INT
&& exact_log2 (const_op) >= 0
&& nonzero_bits (op0, mode) == (unsigned HOST_WIDE_INT) const_op)
{
code = (code == EQ || code == GE || code == GEU ? NE : EQ);
const_op = 0;
}
/* Similarly, if we are comparing a value known to be either -1 or
0 with -1, change it to the opposite comparison against zero. */
if (const_op == -1
&& (code == EQ || code == NE || code == GT || code == LE
|| code == GEU || code == LTU)
&& num_sign_bit_copies (op0, mode) == mode_width)
{
code = (code == EQ || code == LE || code == GEU ? NE : EQ);
const_op = 0;
}
/* Do some canonicalizations based on the comparison code. We prefer
comparisons against zero and then prefer equality comparisons.
If we can reduce the size of a constant, we will do that too. */
switch (code)
{
case LT:
/* < C is equivalent to <= (C - 1) */
if (const_op > 0)
{
const_op -= 1;
code = LE;
/* ... fall through to LE case below. */
}
else
break;
case LE:
/* <= C is equivalent to < (C + 1); we do this for C < 0 */
if (const_op < 0)
{
const_op += 1;
code = LT;
}
/* If we are doing a <= 0 comparison on a value known to have
a zero sign bit, we can replace this with == 0. */
else if (const_op == 0
&& mode_width <= HOST_BITS_PER_WIDE_INT
&& (nonzero_bits (op0, mode)
& ((unsigned HOST_WIDE_INT) 1 << (mode_width - 1)))
== 0)
code = EQ;
break;
case GE:
/* >= C is equivalent to > (C - 1). */
if (const_op > 0)
{
const_op -= 1;
code = GT;
/* ... fall through to GT below. */
}
else
break;
case GT:
/* > C is equivalent to >= (C + 1); we do this for C < 0. */
if (const_op < 0)
{
const_op += 1;
code = GE;
}
/* If we are doing a > 0 comparison on a value known to have
a zero sign bit, we can replace this with != 0. */
else if (const_op == 0
&& mode_width <= HOST_BITS_PER_WIDE_INT
&& (nonzero_bits (op0, mode)
& ((unsigned HOST_WIDE_INT) 1 << (mode_width - 1)))
== 0)
code = NE;
break;
case LTU:
/* < C is equivalent to <= (C - 1). */
if (const_op > 0)
{
const_op -= 1;
code = LEU;
/* ... fall through ... */
}
/* (unsigned) < 0x80000000 is equivalent to >= 0. */
else if (mode_width <= HOST_BITS_PER_WIDE_INT
&& (unsigned HOST_WIDE_INT) const_op
== (unsigned HOST_WIDE_INT) 1 << (mode_width - 1))
{
const_op = 0;
code = GE;
break;
}
else
break;
case LEU:
/* unsigned <= 0 is equivalent to == 0 */
if (const_op == 0)
code = EQ;
/* (unsigned) <= 0x7fffffff is equivalent to >= 0. */
else if (mode_width <= HOST_BITS_PER_WIDE_INT
&& (unsigned HOST_WIDE_INT) const_op
== ((unsigned HOST_WIDE_INT) 1 << (mode_width - 1)) - 1)
{
const_op = 0;
code = GE;
}
break;
case GEU:
/* >= C is equivalent to > (C - 1). */
if (const_op > 1)
{
const_op -= 1;
code = GTU;
/* ... fall through ... */
}
/* (unsigned) >= 0x80000000 is equivalent to < 0. */
else if (mode_width <= HOST_BITS_PER_WIDE_INT
&& (unsigned HOST_WIDE_INT) const_op
== (unsigned HOST_WIDE_INT) 1 << (mode_width - 1))
{
const_op = 0;
code = LT;
break;
}
else
break;
case GTU:
/* unsigned > 0 is equivalent to != 0 */
if (const_op == 0)
code = NE;
/* (unsigned) > 0x7fffffff is equivalent to < 0. */
else if (mode_width <= HOST_BITS_PER_WIDE_INT
&& (unsigned HOST_WIDE_INT) const_op
== ((unsigned HOST_WIDE_INT) 1 << (mode_width - 1)) - 1)
{
const_op = 0;
code = LT;
}
break;
default:
break;
}
*pop1 = GEN_INT (const_op);
return code;
}
/* Simplify a comparison between *POP0 and *POP1 where CODE is the /* Simplify a comparison between *POP0 and *POP1 where CODE is the
comparison code that will be tested. comparison code that will be tested.
...@@ -11000,185 +11226,10 @@ simplify_comparison (enum rtx_code code, rtx *pop0, rtx *pop1) ...@@ -11000,185 +11226,10 @@ simplify_comparison (enum rtx_code code, rtx *pop0, rtx *pop1)
&& (GET_CODE (op0) == COMPARE || COMPARISON_P (op0)))) && (GET_CODE (op0) == COMPARE || COMPARISON_P (op0))))
break; break;
/* Get the constant we are comparing against and turn off all bits /* Try to simplify the compare to constant, possibly changing the
not on in our mode. */ comparison op, and/or changing op1 to zero. */
code = simplify_compare_const (code, op0, &op1);
const_op = INTVAL (op1); const_op = INTVAL (op1);
if (mode != VOIDmode)
const_op = trunc_int_for_mode (const_op, mode);
op1 = GEN_INT (const_op);
/* If we are comparing against a constant power of two and the value
being compared can only have that single bit nonzero (e.g., it was
`and'ed with that bit), we can replace this with a comparison
with zero. */
if (const_op
&& (code == EQ || code == NE || code == GE || code == GEU
|| code == LT || code == LTU)
&& mode_width <= HOST_BITS_PER_WIDE_INT
&& exact_log2 (const_op) >= 0
&& nonzero_bits (op0, mode) == (unsigned HOST_WIDE_INT) const_op)
{
code = (code == EQ || code == GE || code == GEU ? NE : EQ);
op1 = const0_rtx, const_op = 0;
}
/* Similarly, if we are comparing a value known to be either -1 or
0 with -1, change it to the opposite comparison against zero. */
if (const_op == -1
&& (code == EQ || code == NE || code == GT || code == LE
|| code == GEU || code == LTU)
&& num_sign_bit_copies (op0, mode) == mode_width)
{
code = (code == EQ || code == LE || code == GEU ? NE : EQ);
op1 = const0_rtx, const_op = 0;
}
/* Do some canonicalizations based on the comparison code. We prefer
comparisons against zero and then prefer equality comparisons.
If we can reduce the size of a constant, we will do that too. */
switch (code)
{
case LT:
/* < C is equivalent to <= (C - 1) */
if (const_op > 0)
{
const_op -= 1;
op1 = GEN_INT (const_op);
code = LE;
/* ... fall through to LE case below. */
}
else
break;
case LE:
/* <= C is equivalent to < (C + 1); we do this for C < 0 */
if (const_op < 0)
{
const_op += 1;
op1 = GEN_INT (const_op);
code = LT;
}
/* If we are doing a <= 0 comparison on a value known to have
a zero sign bit, we can replace this with == 0. */
else if (const_op == 0
&& mode_width <= HOST_BITS_PER_WIDE_INT
&& (nonzero_bits (op0, mode)
& ((unsigned HOST_WIDE_INT) 1 << (mode_width - 1)))
== 0)
code = EQ;
break;
case GE:
/* >= C is equivalent to > (C - 1). */
if (const_op > 0)
{
const_op -= 1;
op1 = GEN_INT (const_op);
code = GT;
/* ... fall through to GT below. */
}
else
break;
case GT:
/* > C is equivalent to >= (C + 1); we do this for C < 0. */
if (const_op < 0)
{
const_op += 1;
op1 = GEN_INT (const_op);
code = GE;
}
/* If we are doing a > 0 comparison on a value known to have
a zero sign bit, we can replace this with != 0. */
else if (const_op == 0
&& mode_width <= HOST_BITS_PER_WIDE_INT
&& (nonzero_bits (op0, mode)
& ((unsigned HOST_WIDE_INT) 1 << (mode_width - 1)))
== 0)
code = NE;
break;
case LTU:
/* < C is equivalent to <= (C - 1). */
if (const_op > 0)
{
const_op -= 1;
op1 = GEN_INT (const_op);
code = LEU;
/* ... fall through ... */
}
/* (unsigned) < 0x80000000 is equivalent to >= 0. */
else if (mode_width <= HOST_BITS_PER_WIDE_INT
&& (unsigned HOST_WIDE_INT) const_op
== (unsigned HOST_WIDE_INT) 1 << (mode_width - 1))
{
const_op = 0, op1 = const0_rtx;
code = GE;
break;
}
else
break;
case LEU:
/* unsigned <= 0 is equivalent to == 0 */
if (const_op == 0)
code = EQ;
/* (unsigned) <= 0x7fffffff is equivalent to >= 0. */
else if (mode_width <= HOST_BITS_PER_WIDE_INT
&& (unsigned HOST_WIDE_INT) const_op
== ((unsigned HOST_WIDE_INT) 1 << (mode_width - 1)) - 1)
{
const_op = 0, op1 = const0_rtx;
code = GE;
}
break;
case GEU:
/* >= C is equivalent to > (C - 1). */
if (const_op > 1)
{
const_op -= 1;
op1 = GEN_INT (const_op);
code = GTU;
/* ... fall through ... */
}
/* (unsigned) >= 0x80000000 is equivalent to < 0. */
else if (mode_width <= HOST_BITS_PER_WIDE_INT
&& (unsigned HOST_WIDE_INT) const_op
== (unsigned HOST_WIDE_INT) 1 << (mode_width - 1))
{
const_op = 0, op1 = const0_rtx;
code = LT;
break;
}
else
break;
case GTU:
/* unsigned > 0 is equivalent to != 0 */
if (const_op == 0)
code = NE;
/* (unsigned) > 0x7fffffff is equivalent to < 0. */
else if (mode_width <= HOST_BITS_PER_WIDE_INT
&& (unsigned HOST_WIDE_INT) const_op
== ((unsigned HOST_WIDE_INT) 1 << (mode_width - 1)) - 1)
{
const_op = 0, op1 = const0_rtx;
code = LT;
}
break;
default:
break;
}
/* Compute some predicates to simplify code below. */ /* Compute some predicates to simplify code below. */
......
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