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2011-04-26 Andrew Stubbs <ams@codesourcery.com>
Backport from FSF:
2011-04-15 Maxim Kuvyrkov <maxim@codesourcery.com>
gcc/
* combine.c (subst, combine_simlify_rtx): Add new argument, use it
to track processing of conditionals. Update all callers.
(try_combine, simplify_if_then_else): Update.
2011-04-25 Maxim Kuvyrkov <maxim@codesourcery.com>
Eric Botcazou <ebotcazou@adacore.com>
gcc/
* combine.c (combine_simplify_rtx): Avoid mis-simplifying conditionals
for STORE_FLAG_VALUE==-1 case.
=== modified file 'gcc/combine.c'
--- old/gcc/combine.c 2011-02-15 19:46:26 +0000
+++ new/gcc/combine.c 2011-04-26 17:03:58 +0000
@@ -391,8 +391,8 @@
static void undo_all (void);
static void undo_commit (void);
static rtx *find_split_point (rtx *, rtx, bool);
-static rtx subst (rtx, rtx, rtx, int, int);
-static rtx combine_simplify_rtx (rtx, enum machine_mode, int);
+static rtx subst (rtx, rtx, rtx, int, int, int);
+static rtx combine_simplify_rtx (rtx, enum machine_mode, int, int);
static rtx simplify_if_then_else (rtx);
static rtx simplify_set (rtx);
static rtx simplify_logical (rtx);
@@ -3086,12 +3086,12 @@
if (i1)
{
subst_low_luid = DF_INSN_LUID (i1);
- i1src = subst (i1src, pc_rtx, pc_rtx, 0, 0);
+ i1src = subst (i1src, pc_rtx, pc_rtx, 0, 0, 0);
}
else
{
subst_low_luid = DF_INSN_LUID (i2);
- i2src = subst (i2src, pc_rtx, pc_rtx, 0, 0);
+ i2src = subst (i2src, pc_rtx, pc_rtx, 0, 0, 0);
}
}
@@ -3103,7 +3103,7 @@
self-referential RTL when we will be substituting I1SRC for I1DEST
later. Likewise if I0 feeds into I2, either directly or indirectly
through I1, and I0DEST is in I0SRC. */
- newpat = subst (PATTERN (i3), i2dest, i2src, 0,
+ newpat = subst (PATTERN (i3), i2dest, i2src, 0, 0,
(i1_feeds_i2_n && i1dest_in_i1src)
|| ((i0_feeds_i2_n || (i0_feeds_i1_n && i1_feeds_i2_n))
&& i0dest_in_i0src));
@@ -3142,7 +3142,7 @@
copy of I1SRC each time we substitute it, in order to avoid creating
self-referential RTL when we will be substituting I0SRC for I0DEST
later. */
- newpat = subst (newpat, i1dest, i1src, 0,
+ newpat = subst (newpat, i1dest, i1src, 0, 0,
i0_feeds_i1_n && i0dest_in_i0src);
substed_i1 = 1;
@@ -3172,7 +3172,7 @@
n_occurrences = 0;
subst_low_luid = DF_INSN_LUID (i0);
- newpat = subst (newpat, i0dest, i0src, 0, 0);
+ newpat = subst (newpat, i0dest, i0src, 0, 0, 0);
substed_i0 = 1;
}
@@ -3234,7 +3234,7 @@
{
rtx t = i1pat;
if (i0_feeds_i1_n)
- t = subst (t, i0dest, i0src, 0, 0);
+ t = subst (t, i0dest, i0src, 0, 0, 0);
XVECEXP (newpat, 0, --total_sets) = t;
}
@@ -3242,10 +3242,10 @@
{
rtx t = i2pat;
if (i1_feeds_i2_n)
- t = subst (t, i1dest, i1src_copy ? i1src_copy : i1src, 0,
+ t = subst (t, i1dest, i1src_copy ? i1src_copy : i1src, 0, 0,
i0_feeds_i1_n && i0dest_in_i0src);
if ((i0_feeds_i1_n && i1_feeds_i2_n) || i0_feeds_i2_n)
- t = subst (t, i0dest, i0src, 0, 0);
+ t = subst (t, i0dest, i0src, 0, 0, 0);
XVECEXP (newpat, 0, --total_sets) = t;
}
@@ -4914,11 +4914,13 @@
IN_DEST is nonzero if we are processing the SET_DEST of a SET.
+ IN_COND is nonzero if we are on top level of the condition.
+
UNIQUE_COPY is nonzero if each substitution must be unique. We do this
by copying if `n_occurrences' is nonzero. */
static rtx
-subst (rtx x, rtx from, rtx to, int in_dest, int unique_copy)
+subst (rtx x, rtx from, rtx to, int in_dest, int in_cond, int unique_copy)
{
enum rtx_code code = GET_CODE (x);
enum machine_mode op0_mode = VOIDmode;
@@ -4979,7 +4981,7 @@
&& GET_CODE (XVECEXP (x, 0, 0)) == SET
&& GET_CODE (SET_SRC (XVECEXP (x, 0, 0))) == ASM_OPERANDS)
{
- new_rtx = subst (XVECEXP (x, 0, 0), from, to, 0, unique_copy);
+ new_rtx = subst (XVECEXP (x, 0, 0), from, to, 0, 0, unique_copy);
/* If this substitution failed, this whole thing fails. */
if (GET_CODE (new_rtx) == CLOBBER
@@ -4996,7 +4998,7 @@
&& GET_CODE (dest) != CC0
&& GET_CODE (dest) != PC)
{
- new_rtx = subst (dest, from, to, 0, unique_copy);
+ new_rtx = subst (dest, from, to, 0, 0, unique_copy);
/* If this substitution failed, this whole thing fails. */
if (GET_CODE (new_rtx) == CLOBBER
@@ -5042,8 +5044,8 @@
}
else
{
- new_rtx = subst (XVECEXP (x, i, j), from, to, 0,
- unique_copy);
+ new_rtx = subst (XVECEXP (x, i, j), from, to, 0, 0,
+ unique_copy);
/* If this substitution failed, this whole thing
fails. */
@@ -5120,7 +5122,9 @@
&& (code == SUBREG || code == STRICT_LOW_PART
|| code == ZERO_EXTRACT))
|| code == SET)
- && i == 0), unique_copy);
+ && i == 0),
+ code == IF_THEN_ELSE && i == 0,
+ unique_copy);
/* If we found that we will have to reject this combination,
indicate that by returning the CLOBBER ourselves, rather than
@@ -5177,7 +5181,7 @@
/* If X is sufficiently simple, don't bother trying to do anything
with it. */
if (code != CONST_INT && code != REG && code != CLOBBER)
- x = combine_simplify_rtx (x, op0_mode, in_dest);
+ x = combine_simplify_rtx (x, op0_mode, in_dest, in_cond);
if (GET_CODE (x) == code)
break;
@@ -5197,10 +5201,12 @@
expression.
OP0_MODE is the original mode of XEXP (x, 0). IN_DEST is nonzero
- if we are inside a SET_DEST. */
+ if we are inside a SET_DEST. IN_COND is nonzero if we are on the top level
+ of a condition. */
static rtx
-combine_simplify_rtx (rtx x, enum machine_mode op0_mode, int in_dest)
+combine_simplify_rtx (rtx x, enum machine_mode op0_mode, int in_dest,
+ int in_cond)
{
enum rtx_code code = GET_CODE (x);
enum machine_mode mode = GET_MODE (x);
@@ -5255,8 +5261,8 @@
false arms to store-flag values. Be careful to use copy_rtx
here since true_rtx or false_rtx might share RTL with x as a
result of the if_then_else_cond call above. */
- true_rtx = subst (copy_rtx (true_rtx), pc_rtx, pc_rtx, 0, 0);
- false_rtx = subst (copy_rtx (false_rtx), pc_rtx, pc_rtx, 0, 0);
+ true_rtx = subst (copy_rtx (true_rtx), pc_rtx, pc_rtx, 0, 0, 0);
+ false_rtx = subst (copy_rtx (false_rtx), pc_rtx, pc_rtx, 0, 0, 0);
/* If true_rtx and false_rtx are not general_operands, an if_then_else
is unlikely to be simpler. */
@@ -5600,7 +5606,7 @@
{
/* Try to simplify the expression further. */
rtx tor = simplify_gen_binary (IOR, mode, XEXP (x, 0), XEXP (x, 1));
- temp = combine_simplify_rtx (tor, mode, in_dest);
+ temp = combine_simplify_rtx (tor, mode, in_dest, 0);
/* If we could, great. If not, do not go ahead with the IOR
replacement, since PLUS appears in many special purpose
@@ -5693,7 +5699,16 @@
ZERO_EXTRACT is indeed appropriate, it will be placed back by
the call to make_compound_operation in the SET case. */
- if (STORE_FLAG_VALUE == 1
+ if (in_cond)
+ /* Don't apply below optimizations if the caller would
+ prefer a comparison rather than a value.
+ E.g., for the condition in an IF_THEN_ELSE most targets need
+ an explicit comparison. */
+ {
+ ;
+ }
+
+ else if (STORE_FLAG_VALUE == 1
&& new_code == NE && GET_MODE_CLASS (mode) == MODE_INT
&& op1 == const0_rtx
&& mode == GET_MODE (op0)
@@ -5739,7 +5754,10 @@
/* If STORE_FLAG_VALUE is -1, we have cases similar to
those above. */
- if (STORE_FLAG_VALUE == -1
+ if (in_cond)
+ ;
+
+ else if (STORE_FLAG_VALUE == -1
&& new_code == NE && GET_MODE_CLASS (mode) == MODE_INT
&& op1 == const0_rtx
&& (num_sign_bit_copies (op0, mode)
@@ -5937,11 +5955,11 @@
if (reg_mentioned_p (from, true_rtx))
true_rtx = subst (known_cond (copy_rtx (true_rtx), true_code,
from, true_val),
- pc_rtx, pc_rtx, 0, 0);
+ pc_rtx, pc_rtx, 0, 0, 0);
if (reg_mentioned_p (from, false_rtx))
false_rtx = subst (known_cond (copy_rtx (false_rtx), false_code,
from, false_val),
- pc_rtx, pc_rtx, 0, 0);
+ pc_rtx, pc_rtx, 0, 0, 0);
SUBST (XEXP (x, 1), swapped ? false_rtx : true_rtx);
SUBST (XEXP (x, 2), swapped ? true_rtx : false_rtx);
@@ -6158,11 +6176,11 @@
{
temp = subst (simplify_gen_relational (true_code, m, VOIDmode,
cond_op0, cond_op1),
- pc_rtx, pc_rtx, 0, 0);
+ pc_rtx, pc_rtx, 0, 0, 0);
temp = simplify_gen_binary (MULT, m, temp,
simplify_gen_binary (MULT, m, c1,
const_true_rtx));
- temp = subst (temp, pc_rtx, pc_rtx, 0, 0);
+ temp = subst (temp, pc_rtx, pc_rtx, 0, 0, 0);
temp = simplify_gen_binary (op, m, gen_lowpart (m, z), temp);
if (extend_op != UNKNOWN)
|
