/* Fold a constant sub-tree into a single node for C-compiler
- Copyright (C) 1987, 88, 92, 93, 94, 1995 Free Software Foundation, Inc.
+ Copyright (C) 1987, 88, 92-97, 1998 Free Software Foundation, Inc.
This file is part of GNU CC.
You should have received a copy of the GNU General Public License
along with GNU CC; see the file COPYING. If not, write to
-the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
+the Free Software Foundation, 59 Temple Place - Suite 330,
+Boston, MA 02111-1307, USA. */
/*@@ This file should be rewritten to use an arbitrary precision
@@ representation for "struct tree_int_cst" and "struct tree_real_cst".
@@ for cross-compilers. */
-/* The entry points in this file are fold, size_int and size_binop.
+/* The entry points in this file are fold, size_int_wide, size_binop
+ and force_fit_type.
fold takes a tree as argument and returns a simplified tree.
result, assuming the type comes from `sizetype'.
size_int takes an integer value, and creates a tree constant
- with type from `sizetype'. */
-
-#include <stdio.h>
-#include <setjmp.h>
+ with type from `sizetype'.
+
+ force_fit_type takes a constant and prior overflow indicator, and
+ forces the value to fit the type. It returns an overflow indicator. */
+
#include "config.h"
+#include "system.h"
+#include <setjmp.h>
#include "flags.h"
#include "tree.h"
+#include "toplev.h"
/* Handle floating overflow for `const_binop'. */
static jmp_buf float_error;
-static void encode PROTO((HOST_WIDE_INT *, HOST_WIDE_INT, HOST_WIDE_INT));
-static void decode PROTO((HOST_WIDE_INT *, HOST_WIDE_INT *, HOST_WIDE_INT *));
-int div_and_round_double PROTO((enum tree_code, int, HOST_WIDE_INT,
+static void encode PROTO((HOST_WIDE_INT *,
+ HOST_WIDE_INT, HOST_WIDE_INT));
+static void decode PROTO((HOST_WIDE_INT *,
+ HOST_WIDE_INT *, HOST_WIDE_INT *));
+int div_and_round_double PROTO((enum tree_code, int, HOST_WIDE_INT,
HOST_WIDE_INT, HOST_WIDE_INT,
HOST_WIDE_INT, HOST_WIDE_INT *,
HOST_WIDE_INT *, HOST_WIDE_INT *,
HOST_WIDE_INT *));
-static int split_tree PROTO((tree, enum tree_code, tree *, tree *, int *));
-static tree const_binop PROTO((enum tree_code, tree, tree, int));
-static tree fold_convert PROTO((tree, tree));
+static int split_tree PROTO((tree, enum tree_code, tree *,
+ tree *, int *));
+static tree int_const_binop PROTO((enum tree_code, tree, tree, int, int));
+static tree const_binop PROTO((enum tree_code, tree, tree, int));
+static tree fold_convert PROTO((tree, tree));
static enum tree_code invert_tree_comparison PROTO((enum tree_code));
static enum tree_code swap_tree_comparison PROTO((enum tree_code));
-static int truth_value_p PROTO((enum tree_code));
+static int truth_value_p PROTO((enum tree_code));
static int operand_equal_for_comparison_p PROTO((tree, tree, tree));
-static int twoval_comparison_p PROTO((tree, tree *, tree *, int *));
-static tree eval_subst PROTO((tree, tree, tree, tree, tree));
-static tree omit_one_operand PROTO((tree, tree, tree));
+static int twoval_comparison_p PROTO((tree, tree *, tree *, int *));
+static tree eval_subst PROTO((tree, tree, tree, tree, tree));
+static tree omit_one_operand PROTO((tree, tree, tree));
static tree pedantic_omit_one_operand PROTO((tree, tree, tree));
static tree distribute_bit_expr PROTO((enum tree_code, tree, tree, tree));
-static tree make_bit_field_ref PROTO((tree, tree, int, int, int));
+static tree make_bit_field_ref PROTO((tree, tree, int, int, int));
static tree optimize_bit_field_compare PROTO((enum tree_code, tree,
tree, tree));
static tree decode_field_reference PROTO((tree, int *, int *,
enum machine_mode *, int *,
- int *, tree *));
-static int all_ones_mask_p PROTO((tree, int));
-static int simple_operand_p PROTO((tree));
-static tree range_test PROTO((enum tree_code, tree, enum tree_code,
- enum tree_code, tree, tree, tree));
-static tree unextend PROTO((tree, int, int));
-static tree fold_truthop PROTO((enum tree_code, tree, tree, tree));
+ int *, tree *, tree *));
+static int all_ones_mask_p PROTO((tree, int));
+static int simple_operand_p PROTO((tree));
+static tree range_binop PROTO((enum tree_code, tree, tree, int,
+ tree, int));
+static tree make_range PROTO((tree, int *, tree *, tree *));
+static tree build_range_check PROTO((tree, tree, int, tree, tree));
+static int merge_ranges PROTO((int *, tree *, tree *, int, tree, tree,
+ int, tree, tree));
+static tree fold_range_test PROTO((tree));
+static tree unextend PROTO((tree, int, int, tree));
+static tree fold_truthop PROTO((enum tree_code, tree, tree, tree));
static tree strip_compound_expr PROTO((tree, tree));
+static int multiple_of_p PROTO((tree, tree, tree));
+static tree constant_boolean_node PROTO((int, tree));
#ifndef BRANCH_COST
#define BRANCH_COST 1
#endif
-/* Yield nonzero if a signed left shift of A by B bits overflows. */
-#define left_shift_overflows(a, b) ((a) != ((a) << (b)) >> (b))
-
/* Suppose A1 + B1 = SUM1, using 2's complement arithmetic ignoring overflow.
Suppose A, B and SUM have the same respective signs as A1, B1, and SUM1.
Then this yields nonzero if overflow occurred during the addition.
low = TREE_INT_CST_LOW (t);
high = TREE_INT_CST_HIGH (t);
- if (TREE_CODE (TREE_TYPE (t)) == POINTER_TYPE)
+ if (POINTER_TYPE_P (TREE_TYPE (t)))
prec = POINTER_SIZE;
else
prec = TYPE_PRECISION (TREE_TYPE (t));
return;
}
- if (count >= prec)
- count = (unsigned HOST_WIDE_INT) count & prec;
+#ifdef SHIFT_COUNT_TRUNCATED
+ if (SHIFT_COUNT_TRUNCATED)
+ count %= prec;
+#endif
if (count >= HOST_BITS_PER_WIDE_INT)
{
- *hv = (unsigned HOST_WIDE_INT) l1 << count - HOST_BITS_PER_WIDE_INT;
+ *hv = (unsigned HOST_WIDE_INT) l1 << (count - HOST_BITS_PER_WIDE_INT);
*lv = 0;
}
else
{
*hv = (((unsigned HOST_WIDE_INT) h1 << count)
- | ((unsigned HOST_WIDE_INT) l1 >> HOST_BITS_PER_WIDE_INT - count - 1 >> 1));
+ | ((unsigned HOST_WIDE_INT) l1 >> (HOST_BITS_PER_WIDE_INT - count - 1) >> 1));
*lv = (unsigned HOST_WIDE_INT) l1 << count;
}
}
? -((unsigned HOST_WIDE_INT) h1 >> (HOST_BITS_PER_WIDE_INT - 1))
: 0);
- if (count >= prec)
- count = (unsigned HOST_WIDE_INT) count % prec;
+#ifdef SHIFT_COUNT_TRUNCATED
+ if (SHIFT_COUNT_TRUNCATED)
+ count %= prec;
+#endif
if (count >= HOST_BITS_PER_WIDE_INT)
{
*hv = signmask;
- *lv = ((signmask << 2 * HOST_BITS_PER_WIDE_INT - count - 1 << 1)
- | ((unsigned HOST_WIDE_INT) h1 >> count - HOST_BITS_PER_WIDE_INT));
+ *lv = ((signmask << (2 * HOST_BITS_PER_WIDE_INT - count - 1) << 1)
+ | ((unsigned HOST_WIDE_INT) h1 >> (count - HOST_BITS_PER_WIDE_INT)));
}
else
{
*lv = (((unsigned HOST_WIDE_INT) l1 >> count)
- | ((unsigned HOST_WIDE_INT) h1 << HOST_BITS_PER_WIDE_INT - count - 1 << 1));
- *hv = ((signmask << HOST_BITS_PER_WIDE_INT - count)
+ | ((unsigned HOST_WIDE_INT) h1 << (HOST_BITS_PER_WIDE_INT - count - 1) << 1));
+ *hv = ((signmask << (HOST_BITS_PER_WIDE_INT - count))
| ((unsigned HOST_WIDE_INT) h1 >> count));
}
}
HOST_WIDE_INT den[4], quo[4];
register int i, j;
unsigned HOST_WIDE_INT work;
- register int carry = 0;
+ register unsigned HOST_WIDE_INT carry = 0;
HOST_WIDE_INT lnum = lnum_orig;
HOST_WIDE_INT hnum = hnum_orig;
HOST_WIDE_INT lden = lden_orig;
int overflow = 0;
if ((hden == 0) && (lden == 0))
- abort ();
+ overflow = 1, lden = 1;
/* calculate quotient sign and convert operands to unsigned. */
if (!uns)
{
/* Full double precision division,
with thanks to Don Knuth's "Seminumerical Algorithms". */
- int quo_est, scale, num_hi_sig, den_hi_sig;
+ int num_hi_sig, den_hi_sig;
+ unsigned HOST_WIDE_INT quo_est, scale;
/* Find the highest non-zero divisor digit. */
for (i = 4 - 1; ; i--)
return x < 0;
}
#endif /* Target not IEEE */
+
+/* Try to change R into its exact multiplicative inverse in machine mode
+ MODE. Return nonzero function value if successful. */
+
+int
+exact_real_inverse (mode, r)
+ enum machine_mode mode;
+ REAL_VALUE_TYPE *r;
+{
+ union
+ {
+ double d;
+ unsigned short i[4];
+ }x, t, y;
+ int i;
+
+ /* Usually disable if bounds checks are not reliable. */
+ if ((HOST_FLOAT_FORMAT != TARGET_FLOAT_FORMAT) && !flag_pretend_float)
+ return 0;
+
+ /* Set array index to the less significant bits in the unions, depending
+ on the endian-ness of the host doubles.
+ Disable if insufficient information on the data structure. */
+#if HOST_FLOAT_FORMAT == UNKNOWN_FLOAT_FORMAT
+ return 0;
+#else
+#if HOST_FLOAT_FORMAT == VAX_FLOAT_FORMAT
+#define K 2
+#else
+#if HOST_FLOAT_FORMAT == IBM_FLOAT_FORMAT
+#define K 2
+#else
+#define K (2 * HOST_FLOAT_WORDS_BIG_ENDIAN)
+#endif
+#endif
+#endif
+
+ if (setjmp (float_error))
+ {
+ /* Don't do the optimization if there was an arithmetic error. */
+fail:
+ set_float_handler (NULL_PTR);
+ return 0;
+ }
+ set_float_handler (float_error);
+
+ /* Domain check the argument. */
+ x.d = *r;
+ if (x.d == 0.0)
+ goto fail;
+
+#ifdef REAL_INFINITY
+ if (REAL_VALUE_ISINF (x.d) || REAL_VALUE_ISNAN (x.d))
+ goto fail;
+#endif
+
+ /* Compute the reciprocal and check for numerical exactness.
+ It is unnecessary to check all the significand bits to determine
+ whether X is a power of 2. If X is not, then it is impossible for
+ the bottom half significand of both X and 1/X to be all zero bits.
+ Hence we ignore the data structure of the top half and examine only
+ the low order bits of the two significands. */
+ t.d = 1.0 / x.d;
+ if (x.i[K] != 0 || x.i[K + 1] != 0 || t.i[K] != 0 || t.i[K + 1] != 0)
+ goto fail;
+
+ /* Truncate to the required mode and range-check the result. */
+ y.d = REAL_VALUE_TRUNCATE (mode, t.d);
+#ifdef CHECK_FLOAT_VALUE
+ i = 0;
+ if (CHECK_FLOAT_VALUE (mode, y.d, i))
+ goto fail;
+#endif
+
+ /* Fail if truncation changed the value. */
+ if (y.d != t.d || y.d == 0.0)
+ goto fail;
+
+#ifdef REAL_INFINITY
+ if (REAL_VALUE_ISINF (y.d) || REAL_VALUE_ISNAN (y.d))
+ goto fail;
+#endif
+
+ /* Output the reciprocal and return success flag. */
+ set_float_handler (NULL_PTR);
+ *r = y.d;
+ return 1;
+}
#endif /* no REAL_ARITHMETIC */
\f
/* Split a tree IN into a constant and a variable part
return 0;
}
\f
-/* Combine two constants NUM and ARG2 under operation CODE
+/* Combine two integer constants ARG1 and ARG2 under operation CODE
to produce a new constant.
- We assume ARG1 and ARG2 have the same data type,
- or at least are the same kind of constant and the same machine mode.
- If NOTRUNC is nonzero, do not truncate the result to fit the data type. */
+ If NOTRUNC is nonzero, do not truncate the result to fit the data type.
+ If FORSIZE is nonzero, compute overflow for unsigned types. */
static tree
-const_binop (code, arg1, arg2, notrunc)
+int_const_binop (code, arg1, arg2, notrunc, forsize)
enum tree_code code;
register tree arg1, arg2;
- int notrunc;
+ int notrunc, forsize;
{
- if (TREE_CODE (arg1) == INTEGER_CST)
+ HOST_WIDE_INT int1l, int1h, int2l, int2h;
+ HOST_WIDE_INT low, hi;
+ HOST_WIDE_INT garbagel, garbageh;
+ register tree t;
+ int uns = TREE_UNSIGNED (TREE_TYPE (arg1));
+ int overflow = 0;
+ int no_overflow = 0;
+
+ int1l = TREE_INT_CST_LOW (arg1);
+ int1h = TREE_INT_CST_HIGH (arg1);
+ int2l = TREE_INT_CST_LOW (arg2);
+ int2h = TREE_INT_CST_HIGH (arg2);
+
+ switch (code)
{
- register HOST_WIDE_INT int1l = TREE_INT_CST_LOW (arg1);
- register HOST_WIDE_INT int1h = TREE_INT_CST_HIGH (arg1);
- HOST_WIDE_INT int2l = TREE_INT_CST_LOW (arg2);
- HOST_WIDE_INT int2h = TREE_INT_CST_HIGH (arg2);
- HOST_WIDE_INT low, hi;
- HOST_WIDE_INT garbagel, garbageh;
- register tree t;
- int uns = TREE_UNSIGNED (TREE_TYPE (arg1));
- int overflow = 0;
+ case BIT_IOR_EXPR:
+ low = int1l | int2l, hi = int1h | int2h;
+ break;
- switch (code)
- {
- case BIT_IOR_EXPR:
- t = build_int_2 (int1l | int2l, int1h | int2h);
- break;
+ case BIT_XOR_EXPR:
+ low = int1l ^ int2l, hi = int1h ^ int2h;
+ break;
- case BIT_XOR_EXPR:
- t = build_int_2 (int1l ^ int2l, int1h ^ int2h);
- break;
+ case BIT_AND_EXPR:
+ low = int1l & int2l, hi = int1h & int2h;
+ break;
- case BIT_AND_EXPR:
- t = build_int_2 (int1l & int2l, int1h & int2h);
- break;
+ case BIT_ANDTC_EXPR:
+ low = int1l & ~int2l, hi = int1h & ~int2h;
+ break;
- case BIT_ANDTC_EXPR:
- t = build_int_2 (int1l & ~int2l, int1h & ~int2h);
- break;
+ case RSHIFT_EXPR:
+ int2l = - int2l;
+ case LSHIFT_EXPR:
+ /* It's unclear from the C standard whether shifts can overflow.
+ The following code ignores overflow; perhaps a C standard
+ interpretation ruling is needed. */
+ lshift_double (int1l, int1h, int2l,
+ TYPE_PRECISION (TREE_TYPE (arg1)),
+ &low, &hi,
+ !uns);
+ no_overflow = 1;
+ break;
- case RSHIFT_EXPR:
- int2l = - int2l;
- case LSHIFT_EXPR:
- /* It's unclear from the C standard whether shifts can overflow.
- The following code ignores overflow; perhaps a C standard
- interpretation ruling is needed. */
- lshift_double (int1l, int1h, int2l,
- TYPE_PRECISION (TREE_TYPE (arg1)),
- &low, &hi,
- !uns);
- t = build_int_2 (low, hi);
- TREE_TYPE (t) = TREE_TYPE (arg1);
- if (!notrunc)
- force_fit_type (t, 0);
- TREE_OVERFLOW (t) = TREE_OVERFLOW (arg1) | TREE_OVERFLOW (arg2);
- TREE_CONSTANT_OVERFLOW (t)
- = TREE_CONSTANT_OVERFLOW (arg1) | TREE_CONSTANT_OVERFLOW (arg2);
- return t;
+ case RROTATE_EXPR:
+ int2l = - int2l;
+ case LROTATE_EXPR:
+ lrotate_double (int1l, int1h, int2l,
+ TYPE_PRECISION (TREE_TYPE (arg1)),
+ &low, &hi);
+ break;
- case RROTATE_EXPR:
- int2l = - int2l;
- case LROTATE_EXPR:
- lrotate_double (int1l, int1h, int2l,
- TYPE_PRECISION (TREE_TYPE (arg1)),
- &low, &hi);
- t = build_int_2 (low, hi);
- break;
+ case PLUS_EXPR:
+ overflow = add_double (int1l, int1h, int2l, int2h, &low, &hi);
+ break;
- case PLUS_EXPR:
- if (int1h == 0)
- {
- int2l += int1l;
- if ((unsigned HOST_WIDE_INT) int2l < int1l)
- {
- hi = int2h++;
- overflow = int2h < hi;
- }
- t = build_int_2 (int2l, int2h);
- break;
- }
- if (int2h == 0)
- {
- int1l += int2l;
- if ((unsigned HOST_WIDE_INT) int1l < int2l)
- {
- hi = int1h++;
- overflow = int1h < hi;
- }
- t = build_int_2 (int1l, int1h);
- break;
- }
- overflow = add_double (int1l, int1h, int2l, int2h, &low, &hi);
- t = build_int_2 (low, hi);
- break;
+ case MINUS_EXPR:
+ neg_double (int2l, int2h, &low, &hi);
+ add_double (int1l, int1h, low, hi, &low, &hi);
+ overflow = overflow_sum_sign (hi, int2h, int1h);
+ break;
- case MINUS_EXPR:
- if (int2h == 0 && int2l == 0)
- {
- t = build_int_2 (int1l, int1h);
- break;
- }
- neg_double (int2l, int2h, &low, &hi);
- add_double (int1l, int1h, low, hi, &low, &hi);
- overflow = overflow_sum_sign (hi, int2h, int1h);
- t = build_int_2 (low, hi);
- break;
+ case MULT_EXPR:
+ overflow = mul_double (int1l, int1h, int2l, int2h, &low, &hi);
+ break;
- case MULT_EXPR:
- overflow = mul_double (int1l, int1h, int2l, int2h, &low, &hi);
- t = build_int_2 (low, hi);
+ case TRUNC_DIV_EXPR:
+ case FLOOR_DIV_EXPR: case CEIL_DIV_EXPR:
+ case EXACT_DIV_EXPR:
+ /* This is a shortcut for a common special case. */
+ if (int2h == 0 && int2l > 0
+ && ! TREE_CONSTANT_OVERFLOW (arg1)
+ && ! TREE_CONSTANT_OVERFLOW (arg2)
+ && int1h == 0 && int1l >= 0)
+ {
+ if (code == CEIL_DIV_EXPR)
+ int1l += int2l - 1;
+ low = int1l / int2l, hi = 0;
break;
+ }
- case TRUNC_DIV_EXPR:
- case FLOOR_DIV_EXPR: case CEIL_DIV_EXPR:
- case EXACT_DIV_EXPR:
- /* This is a shortcut for a common special case.
- It reduces the number of tree nodes generated
- and saves time. */
- if (int2h == 0 && int2l > 0
- && TREE_TYPE (arg1) == sizetype
- && int1h == 0 && int1l >= 0)
- {
- if (code == CEIL_DIV_EXPR)
- int1l += int2l-1;
- return size_int (int1l / int2l);
- }
- case ROUND_DIV_EXPR:
- if (int2h == 0 && int2l == 1)
- {
- t = build_int_2 (int1l, int1h);
- break;
- }
- if (int1l == int2l && int1h == int2h)
- {
- if ((int1l | int1h) == 0)
- abort ();
- t = build_int_2 (1, 0);
- break;
- }
- overflow = div_and_round_double (code, uns,
- int1l, int1h, int2l, int2h,
- &low, &hi, &garbagel, &garbageh);
- t = build_int_2 (low, hi);
- break;
+ /* ... fall through ... */
- case TRUNC_MOD_EXPR: case ROUND_MOD_EXPR:
- case FLOOR_MOD_EXPR: case CEIL_MOD_EXPR:
- overflow = div_and_round_double (code, uns,
- int1l, int1h, int2l, int2h,
- &garbagel, &garbageh, &low, &hi);
- t = build_int_2 (low, hi);
+ case ROUND_DIV_EXPR:
+ if (int2h == 0 && int2l == 1)
+ {
+ low = int1l, hi = int1h;
break;
+ }
+ if (int1l == int2l && int1h == int2h
+ && ! (int1l == 0 && int1h == 0))
+ {
+ low = 1, hi = 0;
+ break;
+ }
+ overflow = div_and_round_double (code, uns,
+ int1l, int1h, int2l, int2h,
+ &low, &hi, &garbagel, &garbageh);
+ break;
- case MIN_EXPR:
- case MAX_EXPR:
- if (uns)
- {
- low = (((unsigned HOST_WIDE_INT) int1h
- < (unsigned HOST_WIDE_INT) int2h)
- || (((unsigned HOST_WIDE_INT) int1h
- == (unsigned HOST_WIDE_INT) int2h)
- && ((unsigned HOST_WIDE_INT) int1l
- < (unsigned HOST_WIDE_INT) int2l)));
- }
- else
- {
- low = ((int1h < int2h)
- || ((int1h == int2h)
- && ((unsigned HOST_WIDE_INT) int1l
- < (unsigned HOST_WIDE_INT) int2l)));
- }
- if (low == (code == MIN_EXPR))
- t = build_int_2 (int1l, int1h);
- else
- t = build_int_2 (int2l, int2h);
+ case TRUNC_MOD_EXPR:
+ case FLOOR_MOD_EXPR: case CEIL_MOD_EXPR:
+ /* This is a shortcut for a common special case. */
+ if (int2h == 0 && int2l > 0
+ && ! TREE_CONSTANT_OVERFLOW (arg1)
+ && ! TREE_CONSTANT_OVERFLOW (arg2)
+ && int1h == 0 && int1l >= 0)
+ {
+ if (code == CEIL_MOD_EXPR)
+ int1l += int2l - 1;
+ low = int1l % int2l, hi = 0;
break;
+ }
- default:
- abort ();
+ /* ... fall through ... */
+
+ case ROUND_MOD_EXPR:
+ overflow = div_and_round_double (code, uns,
+ int1l, int1h, int2l, int2h,
+ &garbagel, &garbageh, &low, &hi);
+ break;
+
+ case MIN_EXPR:
+ case MAX_EXPR:
+ if (uns)
+ {
+ low = (((unsigned HOST_WIDE_INT) int1h
+ < (unsigned HOST_WIDE_INT) int2h)
+ || (((unsigned HOST_WIDE_INT) int1h
+ == (unsigned HOST_WIDE_INT) int2h)
+ && ((unsigned HOST_WIDE_INT) int1l
+ < (unsigned HOST_WIDE_INT) int2l)));
}
- got_it:
+ else
+ {
+ low = ((int1h < int2h)
+ || ((int1h == int2h)
+ && ((unsigned HOST_WIDE_INT) int1l
+ < (unsigned HOST_WIDE_INT) int2l)));
+ }
+ if (low == (code == MIN_EXPR))
+ low = int1l, hi = int1h;
+ else
+ low = int2l, hi = int2h;
+ break;
+
+ default:
+ abort ();
+ }
+
+ if (TREE_TYPE (arg1) == sizetype && hi == 0
+ && low >= 0
+ && (TYPE_MAX_VALUE (sizetype) == NULL
+ || low <= TREE_INT_CST_LOW (TYPE_MAX_VALUE (sizetype)))
+ && ! overflow
+ && ! TREE_OVERFLOW (arg1) && ! TREE_OVERFLOW (arg2))
+ t = size_int (low);
+ else
+ {
+ t = build_int_2 (low, hi);
TREE_TYPE (t) = TREE_TYPE (arg1);
- TREE_OVERFLOW (t)
- = ((notrunc ? !uns && overflow : force_fit_type (t, overflow && !uns))
- | TREE_OVERFLOW (arg1)
- | TREE_OVERFLOW (arg2));
- TREE_CONSTANT_OVERFLOW (t) = (TREE_OVERFLOW (t)
- | TREE_CONSTANT_OVERFLOW (arg1)
- | TREE_CONSTANT_OVERFLOW (arg2));
- return t;
}
+
+ TREE_OVERFLOW (t)
+ = ((notrunc ? (!uns || forsize) && overflow
+ : force_fit_type (t, (!uns || forsize) && overflow) && ! no_overflow)
+ | TREE_OVERFLOW (arg1)
+ | TREE_OVERFLOW (arg2));
+ /* If we're doing a size calculation, unsigned arithmetic does overflow.
+ So check if force_fit_type truncated the value. */
+ if (forsize
+ && ! TREE_OVERFLOW (t)
+ && (TREE_INT_CST_HIGH (t) != hi
+ || TREE_INT_CST_LOW (t) != low))
+ TREE_OVERFLOW (t) = 1;
+ TREE_CONSTANT_OVERFLOW (t) = (TREE_OVERFLOW (t)
+ | TREE_CONSTANT_OVERFLOW (arg1)
+ | TREE_CONSTANT_OVERFLOW (arg2));
+ return t;
+}
+
+/* Combine two constants ARG1 and ARG2 under operation CODE
+ to produce a new constant.
+ We assume ARG1 and ARG2 have the same data type,
+ or at least are the same kind of constant and the same machine mode.
+
+ If NOTRUNC is nonzero, do not truncate the result to fit the data type. */
+
+static tree
+const_binop (code, arg1, arg2, notrunc)
+ enum tree_code code;
+ register tree arg1, arg2;
+ int notrunc;
+{
+ STRIP_NOPS (arg1); STRIP_NOPS (arg2);
+
+ if (TREE_CODE (arg1) == INTEGER_CST)
+ return int_const_binop (code, arg1, arg2, notrunc, 0);
+
#if ! defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
if (TREE_CODE (arg1) == REAL_CST)
{
#endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
if (TREE_CODE (arg1) == COMPLEX_CST)
{
+ register tree type = TREE_TYPE (arg1);
register tree r1 = TREE_REALPART (arg1);
register tree i1 = TREE_IMAGPART (arg1);
register tree r2 = TREE_REALPART (arg2);
switch (code)
{
case PLUS_EXPR:
- t = build_complex (const_binop (PLUS_EXPR, r1, r2, notrunc),
+ t = build_complex (type,
+ const_binop (PLUS_EXPR, r1, r2, notrunc),
const_binop (PLUS_EXPR, i1, i2, notrunc));
break;
case MINUS_EXPR:
- t = build_complex (const_binop (MINUS_EXPR, r1, r2, notrunc),
+ t = build_complex (type,
+ const_binop (MINUS_EXPR, r1, r2, notrunc),
const_binop (MINUS_EXPR, i1, i2, notrunc));
break;
case MULT_EXPR:
- t = build_complex (const_binop (MINUS_EXPR,
+ t = build_complex (type,
+ const_binop (MINUS_EXPR,
const_binop (MULT_EXPR,
r1, r2, notrunc),
const_binop (MULT_EXPR,
const_binop (MULT_EXPR, i2, i2, notrunc),
notrunc);
- t = build_complex
- (const_binop (INTEGRAL_TYPE_P (TREE_TYPE (r1))
- ? TRUNC_DIV_EXPR : RDIV_EXPR,
- const_binop (PLUS_EXPR,
- const_binop (MULT_EXPR, r1, r2,
- notrunc),
- const_binop (MULT_EXPR, i1, i2,
- notrunc),
- notrunc),
- magsquared, notrunc),
- const_binop (INTEGRAL_TYPE_P (TREE_TYPE (r1))
- ? TRUNC_DIV_EXPR : RDIV_EXPR,
- const_binop (MINUS_EXPR,
- const_binop (MULT_EXPR, i1, r2,
- notrunc),
- const_binop (MULT_EXPR, r1, i2,
- notrunc),
- notrunc),
- magsquared, notrunc));
+ t = build_complex (type,
+ const_binop
+ (INTEGRAL_TYPE_P (TREE_TYPE (r1))
+ ? TRUNC_DIV_EXPR : RDIV_EXPR,
+ const_binop (PLUS_EXPR,
+ const_binop (MULT_EXPR, r1, r2,
+ notrunc),
+ const_binop (MULT_EXPR, i1, i2,
+ notrunc),
+ notrunc),
+ magsquared, notrunc),
+ const_binop
+ (INTEGRAL_TYPE_P (TREE_TYPE (r1))
+ ? TRUNC_DIV_EXPR : RDIV_EXPR,
+ const_binop (MINUS_EXPR,
+ const_binop (MULT_EXPR, i1, r2,
+ notrunc),
+ const_binop (MULT_EXPR, r1, i2,
+ notrunc),
+ notrunc),
+ magsquared, notrunc));
}
break;
default:
abort ();
}
- TREE_TYPE (t) = TREE_TYPE (arg1);
return t;
}
return 0;
}
\f
-/* Return an INTEGER_CST with value V and type from `sizetype'. */
+/* Return an INTEGER_CST with value V . The type is determined by bit_p:
+ if it is zero, the type is taken from sizetype; if it is one, the type
+ is taken from bitsizetype. */
tree
-size_int (number)
- unsigned HOST_WIDE_INT number;
+size_int_wide (number, high, bit_p)
+ unsigned HOST_WIDE_INT number, high;
+ int bit_p;
{
register tree t;
/* Type-size nodes already made for small sizes. */
- static tree size_table[2*HOST_BITS_PER_WIDE_INT + 1];
+ static tree size_table[2*HOST_BITS_PER_WIDE_INT + 1][2];
- if (number < 2*HOST_BITS_PER_WIDE_INT + 1
- && size_table[number] != 0)
- return size_table[number];
- if (number < 2*HOST_BITS_PER_WIDE_INT + 1)
+ if (number < 2*HOST_BITS_PER_WIDE_INT + 1 && ! high
+ && size_table[number][bit_p] != 0)
+ return size_table[number][bit_p];
+ if (number < 2*HOST_BITS_PER_WIDE_INT + 1 && ! high)
{
push_obstacks_nochange ();
/* Make this a permanent node. */
end_temporary_allocation ();
t = build_int_2 (number, 0);
- TREE_TYPE (t) = sizetype;
- size_table[number] = t;
+ TREE_TYPE (t) = bit_p ? bitsizetype : sizetype;
+ size_table[number][bit_p] = t;
pop_obstacks ();
}
else
{
- t = build_int_2 (number, 0);
- TREE_TYPE (t) = sizetype;
+ t = build_int_2 (number, high);
+ TREE_TYPE (t) = bit_p ? bitsizetype : sizetype;
+ TREE_OVERFLOW (t) = TREE_CONSTANT_OVERFLOW (t) = force_fit_type (t, 0);
}
return t;
}
if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == INTEGER_CST)
{
/* And some specific cases even faster than that. */
- if (code == PLUS_EXPR
- && TREE_INT_CST_LOW (arg0) == 0
- && TREE_INT_CST_HIGH (arg0) == 0)
+ if (code == PLUS_EXPR && integer_zerop (arg0))
return arg1;
- if (code == MINUS_EXPR
- && TREE_INT_CST_LOW (arg1) == 0
- && TREE_INT_CST_HIGH (arg1) == 0)
+ else if ((code == MINUS_EXPR || code == PLUS_EXPR)
+ && integer_zerop (arg1))
return arg0;
- if (code == MULT_EXPR
- && TREE_INT_CST_LOW (arg0) == 1
- && TREE_INT_CST_HIGH (arg0) == 0)
+ else if (code == MULT_EXPR && integer_onep (arg0))
return arg1;
+
/* Handle general case of two integer constants. */
- return const_binop (code, arg0, arg1, 1);
+ return int_const_binop (code, arg0, arg1, 0, 1);
}
if (arg0 == error_mark_node || arg1 == error_mark_node)
return fold (build (code, sizetype, arg0, arg1));
}
+
+/* Combine operands OP1 and OP2 with arithmetic operation CODE.
+ CODE is a tree code. Data type is taken from `ssizetype',
+ If the operands are constant, so is the result. */
+
+tree
+ssize_binop (code, arg0, arg1)
+ enum tree_code code;
+ tree arg0, arg1;
+{
+ /* Handle the special case of two integer constants faster. */
+ if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == INTEGER_CST)
+ {
+ /* And some specific cases even faster than that. */
+ if (code == PLUS_EXPR && integer_zerop (arg0))
+ return arg1;
+ else if ((code == MINUS_EXPR || code == PLUS_EXPR)
+ && integer_zerop (arg1))
+ return arg0;
+ else if (code == MULT_EXPR && integer_onep (arg0))
+ return arg1;
+
+ /* Handle general case of two integer constants. We convert
+ arg0 to ssizetype because int_const_binop uses its type for the
+ return value. */
+ arg0 = convert (ssizetype, arg0);
+ return int_const_binop (code, arg0, arg1, 0, 0);
+ }
+
+ if (arg0 == error_mark_node || arg1 == error_mark_node)
+ return error_mark_node;
+
+ return fold (build (code, ssizetype, arg0, arg1));
+}
\f
/* Given T, a tree representing type conversion of ARG1, a constant,
return a constant tree representing the result of conversion. */
register tree type = TREE_TYPE (t);
int overflow = 0;
- if (TREE_CODE (type) == POINTER_TYPE || INTEGRAL_TYPE_P (type))
+ if (POINTER_TYPE_P (type) || INTEGRAL_TYPE_P (type))
{
if (TREE_CODE (arg1) == INTEGER_CST)
{
/* Indicate an overflow if (1) ARG1 already overflowed,
or (2) force_fit_type indicates an overflow.
Tell force_fit_type that an overflow has already occurred
- if ARG1 is a too-large unsigned value and T is signed. */
+ if ARG1 is a too-large unsigned value and T is signed.
+ But don't indicate an overflow if converting a pointer. */
TREE_OVERFLOW (t)
- = (TREE_OVERFLOW (arg1)
- | force_fit_type (t,
- (TREE_INT_CST_HIGH (arg1) < 0
- & (TREE_UNSIGNED (type)
- < TREE_UNSIGNED (TREE_TYPE (arg1))))));
+ = ((force_fit_type (t,
+ (TREE_INT_CST_HIGH (arg1) < 0
+ && (TREE_UNSIGNED (type)
+ < TREE_UNSIGNED (TREE_TYPE (arg1)))))
+ && ! POINTER_TYPE_P (TREE_TYPE (arg1)))
+ || TREE_OVERFLOW (arg1));
TREE_CONSTANT_OVERFLOW (t)
= TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg1);
}
REAL_VALUE_TYPE x;
REAL_VALUE_TYPE l;
REAL_VALUE_TYPE u;
+ tree type1 = TREE_TYPE (arg1);
+ int no_upper_bound;
x = TREE_REAL_CST (arg1);
- l = real_value_from_int_cst (TYPE_MIN_VALUE (type));
- u = real_value_from_int_cst (TYPE_MAX_VALUE (type));
+ l = real_value_from_int_cst (type1, TYPE_MIN_VALUE (type));
+
+ no_upper_bound = (TYPE_MAX_VALUE (type) == NULL);
+ if (!no_upper_bound)
+ u = real_value_from_int_cst (type1, TYPE_MAX_VALUE (type));
+
/* See if X will be in range after truncation towards 0.
To compensate for truncation, move the bounds away from 0,
but reject if X exactly equals the adjusted bounds. */
#ifdef REAL_ARITHMETIC
REAL_ARITHMETIC (l, MINUS_EXPR, l, dconst1);
- REAL_ARITHMETIC (u, PLUS_EXPR, u, dconst1);
+ if (!no_upper_bound)
+ REAL_ARITHMETIC (u, PLUS_EXPR, u, dconst1);
#else
l--;
- u++;
+ if (!no_upper_bound)
+ u++;
#endif
/* If X is a NaN, use zero instead and show we have an overflow.
Otherwise, range check. */
if (REAL_VALUE_ISNAN (x))
overflow = 1, x = dconst0;
- else if (! (REAL_VALUES_LESS (l, x) && REAL_VALUES_LESS (x, u)))
+ else if (! (REAL_VALUES_LESS (l, x)
+ && !no_upper_bound
+ && REAL_VALUES_LESS (x, u)))
overflow = 1;
#ifndef REAL_ARITHMETIC
if (TREE_CODE (arg1) == REAL_CST)
{
if (REAL_VALUE_ISNAN (TREE_REAL_CST (arg1)))
- return arg1;
+ {
+ t = arg1;
+ TREE_TYPE (arg1) = type;
+ return t;
+ }
else if (setjmp (float_error))
{
overflow = 1;
STRIP_NOPS (arg0);
STRIP_NOPS (arg1);
- /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal.
- We don't care about side effects in that case because the SAVE_EXPR
- takes care of that for us. */
- if (TREE_CODE (arg0) == SAVE_EXPR && arg0 == arg1)
- return ! only_const;
-
- if (TREE_SIDE_EFFECTS (arg0) || TREE_SIDE_EFFECTS (arg1))
+ if (TREE_CODE (arg0) != TREE_CODE (arg1)
+ /* This is needed for conversions and for COMPONENT_REF.
+ Might as well play it safe and always test this. */
+ || TYPE_MODE (TREE_TYPE (arg0)) != TYPE_MODE (TREE_TYPE (arg1)))
return 0;
- if (TREE_CODE (arg0) == TREE_CODE (arg1)
- && TREE_CODE (arg0) == ADDR_EXPR
- && TREE_OPERAND (arg0, 0) == TREE_OPERAND (arg1, 0))
- return 1;
-
- if (TREE_CODE (arg0) == TREE_CODE (arg1)
- && TREE_CODE (arg0) == INTEGER_CST
- && TREE_INT_CST_LOW (arg0) == TREE_INT_CST_LOW (arg1)
- && TREE_INT_CST_HIGH (arg0) == TREE_INT_CST_HIGH (arg1))
+ /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal.
+ We don't care about side effects in that case because the SAVE_EXPR
+ takes care of that for us. In all other cases, two expressions are
+ equal if they have no side effects. If we have two identical
+ expressions with side effects that should be treated the same due
+ to the only side effects being identical SAVE_EXPR's, that will
+ be detected in the recursive calls below. */
+ if (arg0 == arg1 && ! only_const
+ && (TREE_CODE (arg0) == SAVE_EXPR
+ || (! TREE_SIDE_EFFECTS (arg0) && ! TREE_SIDE_EFFECTS (arg1))))
return 1;
- /* Detect when real constants are equal. */
- if (TREE_CODE (arg0) == TREE_CODE (arg1)
- && TREE_CODE (arg0) == REAL_CST)
- return !bcmp ((char *) &TREE_REAL_CST (arg0),
- (char *) &TREE_REAL_CST (arg1),
- sizeof (REAL_VALUE_TYPE));
+ /* Next handle constant cases, those for which we can return 1 even
+ if ONLY_CONST is set. */
+ if (TREE_CONSTANT (arg0) && TREE_CONSTANT (arg1))
+ switch (TREE_CODE (arg0))
+ {
+ case INTEGER_CST:
+ return (! TREE_CONSTANT_OVERFLOW (arg0)
+ && ! TREE_CONSTANT_OVERFLOW (arg1)
+ && TREE_INT_CST_LOW (arg0) == TREE_INT_CST_LOW (arg1)
+ && TREE_INT_CST_HIGH (arg0) == TREE_INT_CST_HIGH (arg1));
+
+ case REAL_CST:
+ return (! TREE_CONSTANT_OVERFLOW (arg0)
+ && ! TREE_CONSTANT_OVERFLOW (arg1)
+ && REAL_VALUES_IDENTICAL (TREE_REAL_CST (arg0),
+ TREE_REAL_CST (arg1)));
+
+ case COMPLEX_CST:
+ return (operand_equal_p (TREE_REALPART (arg0), TREE_REALPART (arg1),
+ only_const)
+ && operand_equal_p (TREE_IMAGPART (arg0), TREE_IMAGPART (arg1),
+ only_const));
+
+ case STRING_CST:
+ return (TREE_STRING_LENGTH (arg0) == TREE_STRING_LENGTH (arg1)
+ && ! strncmp (TREE_STRING_POINTER (arg0),
+ TREE_STRING_POINTER (arg1),
+ TREE_STRING_LENGTH (arg0)));
+
+ case ADDR_EXPR:
+ return operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 0),
+ 0);
+ default:
+ break;
+ }
if (only_const)
return 0;
- if (arg0 == arg1)
- return 1;
-
- if (TREE_CODE (arg0) != TREE_CODE (arg1))
- return 0;
- /* This is needed for conversions and for COMPONENT_REF.
- Might as well play it safe and always test this. */
- if (TYPE_MODE (TREE_TYPE (arg0)) != TYPE_MODE (TREE_TYPE (arg1)))
- return 0;
-
switch (TREE_CODE_CLASS (TREE_CODE (arg0)))
{
case '1':
case '<':
case '2':
- return (operand_equal_p (TREE_OPERAND (arg0, 0),
- TREE_OPERAND (arg1, 0), 0)
+ if (operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 0), 0)
+ && operand_equal_p (TREE_OPERAND (arg0, 1), TREE_OPERAND (arg1, 1),
+ 0))
+ return 1;
+
+ /* For commutative ops, allow the other order. */
+ return ((TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MULT_EXPR
+ || TREE_CODE (arg0) == MIN_EXPR || TREE_CODE (arg0) == MAX_EXPR
+ || TREE_CODE (arg0) == BIT_IOR_EXPR
+ || TREE_CODE (arg0) == BIT_XOR_EXPR
+ || TREE_CODE (arg0) == BIT_AND_EXPR
+ || TREE_CODE (arg0) == NE_EXPR || TREE_CODE (arg0) == EQ_EXPR)
+ && operand_equal_p (TREE_OPERAND (arg0, 0),
+ TREE_OPERAND (arg1, 1), 0)
&& operand_equal_p (TREE_OPERAND (arg0, 1),
- TREE_OPERAND (arg1, 1), 0));
+ TREE_OPERAND (arg1, 0), 0));
case 'r':
switch (TREE_CODE (arg0))
TREE_OPERAND (arg1, 1), 0)
&& operand_equal_p (TREE_OPERAND (arg0, 2),
TREE_OPERAND (arg1, 2), 0));
+ default:
+ return 0;
}
- break;
+
+ default:
+ return 0;
}
-
- return 0;
}
\f
/* Similar to operand_equal_p, but see if ARG0 might have been made by
tree other;
{
int unsignedp1, unsignedpo;
- tree primarg1, primother;
+ tree primarg0, primarg1, primother;
unsigned correct_width;
if (operand_equal_p (arg0, arg1, 0))
|| ! INTEGRAL_TYPE_P (TREE_TYPE (arg1)))
return 0;
+ /* Discard any conversions that don't change the modes of ARG0 and ARG1
+ and see if the inner values are the same. This removes any
+ signedness comparison, which doesn't matter here. */
+ primarg0 = arg0, primarg1 = arg1;
+ STRIP_NOPS (primarg0); STRIP_NOPS (primarg1);
+ if (operand_equal_p (primarg0, primarg1, 0))
+ return 1;
+
/* Duplicate what shorten_compare does to ARG1 and see if that gives the
actual comparison operand, ARG0.
return 0;
return 1;
- }
- return 0;
+ default:
+ return 0;
+ }
}
\f
/* ARG is a tree that is known to contain just arithmetic operations and
old0, new0, old1, new1),
eval_subst (TREE_OPERAND (arg, 2),
old0, new0, old1, new1)));
+ default:
+ break;
}
+ /* fall through (???) */
case '<':
{
return fold (build (code, type, arg0, arg1));
}
- }
- return arg;
+ default:
+ return arg;
+ }
}
\f
/* Return a tree for the case when the result of an expression is RESULT
case SAVE_EXPR:
return build1 (TRUTH_NOT_EXPR, type, arg);
+
+ case CLEANUP_POINT_EXPR:
+ return build1 (CLEANUP_POINT_EXPR, type,
+ invert_truthvalue (TREE_OPERAND (arg, 0)));
+
+ default:
+ break;
}
if (TREE_CODE (TREE_TYPE (arg)) != BOOLEAN_TYPE)
abort ();
int unsignedp;
{
tree result = build (BIT_FIELD_REF, type, inner,
- size_int (bitsize), size_int (bitpos));
+ size_int (bitsize), bitsize_int (bitpos, 0L));
TREE_UNSIGNED (result) = unsignedp;
tree lhs, rhs;
{
int lbitpos, lbitsize, rbitpos, rbitsize;
- int lnbitpos, lnbitsize, rnbitpos, rnbitsize;
+ int lnbitpos, lnbitsize, rnbitpos = 0, rnbitsize = 0;
tree type = TREE_TYPE (lhs);
tree signed_type, unsigned_type;
int const_p = TREE_CODE (rhs) == INTEGER_CST;
- enum machine_mode lmode, rmode, lnmode, rnmode;
+ enum machine_mode lmode, rmode, lnmode, rnmode = VOIDmode;
int lunsignedp, runsignedp;
int lvolatilep = 0, rvolatilep = 0;
- tree linner, rinner;
+ int alignment;
+ tree linner, rinner = NULL_TREE;
tree mask;
tree offset;
if the same as the size of the underlying object, we aren't doing an
extraction at all and so can do nothing. */
linner = get_inner_reference (lhs, &lbitsize, &lbitpos, &offset, &lmode,
- &lunsignedp, &lvolatilep);
+ &lunsignedp, &lvolatilep, &alignment);
if (linner == lhs || lbitsize == GET_MODE_BITSIZE (lmode) || lbitsize < 0
|| offset != 0)
return 0;
{
/* If this is not a constant, we can only do something if bit positions,
sizes, and signedness are the same. */
- rinner = get_inner_reference (rhs, &rbitsize, &rbitpos, &offset,
- &rmode, &runsignedp, &rvolatilep);
+ rinner = get_inner_reference (rhs, &rbitsize, &rbitpos, &offset, &rmode,
+ &runsignedp, &rvolatilep, &alignment);
if (rinner == rhs || lbitpos != rbitpos || lbitsize != rbitsize
|| lunsignedp != runsignedp || offset != 0)
*PMASK is set to the mask used. This is either contained in a
BIT_AND_EXPR or derived from the width of the field.
+ *PAND_MASK is set to the mask found in a BIT_AND_EXPR, if any.
+
Return 0 if this is not a component reference or is one that we can't
do anything with. */
static tree
decode_field_reference (exp, pbitsize, pbitpos, pmode, punsignedp,
- pvolatilep, pmask)
+ pvolatilep, pmask, pand_mask)
tree exp;
int *pbitsize, *pbitpos;
enum machine_mode *pmode;
int *punsignedp, *pvolatilep;
tree *pmask;
+ tree *pand_mask;
{
tree and_mask = 0;
tree mask, inner, offset;
tree unsigned_type;
int precision;
+ int alignment;
/* All the optimizations using this function assume integer fields.
There are problems with FP fields since the type_for_size call
inner = get_inner_reference (exp, pbitsize, pbitpos, &offset, pmode,
- punsignedp, pvolatilep);
+ punsignedp, pvolatilep, &alignment);
if ((inner == exp && and_mask == 0)
|| *pbitsize < 0 || offset != 0)
return 0;
convert (unsigned_type, and_mask), mask));
*pmask = mask;
+ *pand_mask = and_mask;
return inner;
}
size_int (precision - size), 0));
}
-/* Subroutine for fold_truthop: determine if an operand is simple enough
- to be evaluated unconditionally. */
+/* Subroutine for fold_truthop: determine if an operand is simple enough
+ to be evaluated unconditionally. */
+
+static int
+simple_operand_p (exp)
+ tree exp;
+{
+ /* Strip any conversions that don't change the machine mode. */
+ while ((TREE_CODE (exp) == NOP_EXPR
+ || TREE_CODE (exp) == CONVERT_EXPR)
+ && (TYPE_MODE (TREE_TYPE (exp))
+ == TYPE_MODE (TREE_TYPE (TREE_OPERAND (exp, 0)))))
+ exp = TREE_OPERAND (exp, 0);
+
+ return (TREE_CODE_CLASS (TREE_CODE (exp)) == 'c'
+ || (TREE_CODE_CLASS (TREE_CODE (exp)) == 'd'
+ && ! TREE_ADDRESSABLE (exp)
+ && ! TREE_THIS_VOLATILE (exp)
+ && ! DECL_NONLOCAL (exp)
+ /* Don't regard global variables as simple. They may be
+ allocated in ways unknown to the compiler (shared memory,
+ #pragma weak, etc). */
+ && ! TREE_PUBLIC (exp)
+ && ! DECL_EXTERNAL (exp)
+ /* Loading a static variable is unduly expensive, but global
+ registers aren't expensive. */
+ && (! TREE_STATIC (exp) || DECL_REGISTER (exp))));
+}
+\f
+/* The following functions are subroutines to fold_range_test and allow it to
+ try to change a logical combination of comparisons into a range test.
+
+ For example, both
+ X == 2 && X == 3 && X == 4 && X == 5
+ and
+ X >= 2 && X <= 5
+ are converted to
+ (unsigned) (X - 2) <= 3
+
+ We describe each set of comparisons as being either inside or outside
+ a range, using a variable named like IN_P, and then describe the
+ range with a lower and upper bound. If one of the bounds is omitted,
+ it represents either the highest or lowest value of the type.
+
+ In the comments below, we represent a range by two numbers in brackets
+ preceded by a "+" to designate being inside that range, or a "-" to
+ designate being outside that range, so the condition can be inverted by
+ flipping the prefix. An omitted bound is represented by a "-". For
+ example, "- [-, 10]" means being outside the range starting at the lowest
+ possible value and ending at 10, in other words, being greater than 10.
+ The range "+ [-, -]" is always true and hence the range "- [-, -]" is
+ always false.
+
+ We set up things so that the missing bounds are handled in a consistent
+ manner so neither a missing bound nor "true" and "false" need to be
+ handled using a special case. */
+
+/* Return the result of applying CODE to ARG0 and ARG1, but handle the case
+ of ARG0 and/or ARG1 being omitted, meaning an unlimited range. UPPER0_P
+ and UPPER1_P are nonzero if the respective argument is an upper bound
+ and zero for a lower. TYPE, if nonzero, is the type of the result; it
+ must be specified for a comparison. ARG1 will be converted to ARG0's
+ type if both are specified. */
+
+static tree
+range_binop (code, type, arg0, upper0_p, arg1, upper1_p)
+ enum tree_code code;
+ tree type;
+ tree arg0, arg1;
+ int upper0_p, upper1_p;
+{
+ tree tem;
+ int result;
+ int sgn0, sgn1;
+
+ /* If neither arg represents infinity, do the normal operation.
+ Else, if not a comparison, return infinity. Else handle the special
+ comparison rules. Note that most of the cases below won't occur, but
+ are handled for consistency. */
+
+ if (arg0 != 0 && arg1 != 0)
+ {
+ tem = fold (build (code, type != 0 ? type : TREE_TYPE (arg0),
+ arg0, convert (TREE_TYPE (arg0), arg1)));
+ STRIP_NOPS (tem);
+ return TREE_CODE (tem) == INTEGER_CST ? tem : 0;
+ }
+
+ if (TREE_CODE_CLASS (code) != '<')
+ return 0;
+
+ /* Set SGN[01] to -1 if ARG[01] is a lower bound, 1 for upper, and 0
+ for neither. Then compute our result treating them as never equal
+ and comparing bounds to non-bounds as above. */
+ sgn0 = arg0 != 0 ? 0 : (upper0_p ? 1 : -1);
+ sgn1 = arg1 != 0 ? 0 : (upper1_p ? 1 : -1);
+ switch (code)
+ {
+ case EQ_EXPR: case NE_EXPR:
+ result = (code == NE_EXPR);
+ break;
+ case LT_EXPR: case LE_EXPR:
+ result = sgn0 < sgn1;
+ break;
+ case GT_EXPR: case GE_EXPR:
+ result = sgn0 > sgn1;
+ break;
+ default:
+ abort ();
+ }
+
+ return convert (type, result ? integer_one_node : integer_zero_node);
+}
+\f
+/* Given EXP, a logical expression, set the range it is testing into
+ variables denoted by PIN_P, PLOW, and PHIGH. Return the expression
+ actually being tested. *PLOW and *PHIGH will have be made the same type
+ as the returned expression. If EXP is not a comparison, we will most
+ likely not be returning a useful value and range. */
+
+static tree
+make_range (exp, pin_p, plow, phigh)
+ tree exp;
+ int *pin_p;
+ tree *plow, *phigh;
+{
+ enum tree_code code;
+ tree arg0, arg1, type = NULL_TREE;
+ int in_p, n_in_p;
+ tree low, high, n_low, n_high;
+
+ /* Start with simply saying "EXP != 0" and then look at the code of EXP
+ and see if we can refine the range. Some of the cases below may not
+ happen, but it doesn't seem worth worrying about this. We "continue"
+ the outer loop when we've changed something; otherwise we "break"
+ the switch, which will "break" the while. */
+
+ in_p = 0, low = high = convert (TREE_TYPE (exp), integer_zero_node);
+
+ while (1)
+ {
+ code = TREE_CODE (exp);
+ arg0 = TREE_OPERAND (exp, 0), arg1 = TREE_OPERAND (exp, 1);
+ if (TREE_CODE_CLASS (code) == '<' || TREE_CODE_CLASS (code) == '1'
+ || TREE_CODE_CLASS (code) == '2')
+ type = TREE_TYPE (arg0);
+
+ switch (code)
+ {
+ case TRUTH_NOT_EXPR:
+ in_p = ! in_p, exp = arg0;
+ continue;
+
+ case EQ_EXPR: case NE_EXPR:
+ case LT_EXPR: case LE_EXPR: case GE_EXPR: case GT_EXPR:
+ /* We can only do something if the range is testing for zero
+ and if the second operand is an integer constant. Note that
+ saying something is "in" the range we make is done by
+ complementing IN_P since it will set in the initial case of
+ being not equal to zero; "out" is leaving it alone. */
+ if (low == 0 || high == 0
+ || ! integer_zerop (low) || ! integer_zerop (high)
+ || TREE_CODE (arg1) != INTEGER_CST)
+ break;
+
+ switch (code)
+ {
+ case NE_EXPR: /* - [c, c] */
+ low = high = arg1;
+ break;
+ case EQ_EXPR: /* + [c, c] */
+ in_p = ! in_p, low = high = arg1;
+ break;
+ case GT_EXPR: /* - [-, c] */
+ low = 0, high = arg1;
+ break;
+ case GE_EXPR: /* + [c, -] */
+ in_p = ! in_p, low = arg1, high = 0;
+ break;
+ case LT_EXPR: /* - [c, -] */
+ low = arg1, high = 0;
+ break;
+ case LE_EXPR: /* + [-, c] */
+ in_p = ! in_p, low = 0, high = arg1;
+ break;
+ default:
+ abort ();
+ }
+
+ exp = arg0;
+
+ /* If this is an unsigned comparison, we also know that EXP is
+ greater than or equal to zero. We base the range tests we make
+ on that fact, so we record it here so we can parse existing
+ range tests. */
+ if (TREE_UNSIGNED (type) && (low == 0 || high == 0))
+ {
+ if (! merge_ranges (&n_in_p, &n_low, &n_high, in_p, low, high,
+ 1, convert (type, integer_zero_node),
+ NULL_TREE))
+ break;
+
+ in_p = n_in_p, low = n_low, high = n_high;
+
+ /* If the high bound is missing, reverse the range so it
+ goes from zero to the low bound minus 1. */
+ if (high == 0)
+ {
+ in_p = ! in_p;
+ high = range_binop (MINUS_EXPR, NULL_TREE, low, 0,
+ integer_one_node, 0);
+ low = convert (type, integer_zero_node);
+ }
+ }
+ continue;
+
+ case NEGATE_EXPR:
+ /* (-x) IN [a,b] -> x in [-b, -a] */
+ n_low = range_binop (MINUS_EXPR, type,
+ convert (type, integer_zero_node), 0, high, 1);
+ n_high = range_binop (MINUS_EXPR, type,
+ convert (type, integer_zero_node), 0, low, 0);
+ low = n_low, high = n_high;
+ exp = arg0;
+ continue;
+
+ case BIT_NOT_EXPR:
+ /* ~ X -> -X - 1 */
+ exp = build (MINUS_EXPR, type, build1 (NEGATE_EXPR, type, arg0),
+ convert (type, integer_one_node));
+ continue;
+
+ case PLUS_EXPR: case MINUS_EXPR:
+ if (TREE_CODE (arg1) != INTEGER_CST)
+ break;
+
+ /* If EXP is signed, any overflow in the computation is undefined,
+ so we don't worry about it so long as our computations on
+ the bounds don't overflow. For unsigned, overflow is defined
+ and this is exactly the right thing. */
+ n_low = range_binop (code == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR,
+ type, low, 0, arg1, 0);
+ n_high = range_binop (code == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR,
+ type, high, 1, arg1, 0);
+ if ((n_low != 0 && TREE_OVERFLOW (n_low))
+ || (n_high != 0 && TREE_OVERFLOW (n_high)))
+ break;
+
+ /* Check for an unsigned range which has wrapped around the maximum
+ value thus making n_high < n_low, and normalize it. */
+ if (n_low && n_high && tree_int_cst_lt (n_high, n_low))
+ {
+ low = range_binop (PLUS_EXPR, type, n_high, 0,
+ integer_one_node, 0);
+ high = range_binop (MINUS_EXPR, type, n_low, 0,
+ integer_one_node, 0);
+ in_p = ! in_p;
+ }
+ else
+ low = n_low, high = n_high;
+
+ exp = arg0;
+ continue;
+
+ case NOP_EXPR: case NON_LVALUE_EXPR: case CONVERT_EXPR:
+ if (! INTEGRAL_TYPE_P (type)
+ || (low != 0 && ! int_fits_type_p (low, type))
+ || (high != 0 && ! int_fits_type_p (high, type)))
+ break;
+
+ n_low = low, n_high = high;
+
+ if (n_low != 0)
+ n_low = convert (type, n_low);
+
+ if (n_high != 0)
+ n_high = convert (type, n_high);
+
+ /* If we're converting from an unsigned to a signed type,
+ we will be doing the comparison as unsigned. The tests above
+ have already verified that LOW and HIGH are both positive.
+
+ So we have to make sure that the original unsigned value will
+ be interpreted as positive. */
+ if (TREE_UNSIGNED (type) && ! TREE_UNSIGNED (TREE_TYPE (exp)))
+ {
+ tree equiv_type = type_for_mode (TYPE_MODE (type), 1);
+ tree high_positive;
+
+ /* A range without an upper bound is, naturally, unbounded.
+ Since convert would have cropped a very large value, use
+ the max value for the destination type. */
+
+ high_positive = TYPE_MAX_VALUE (equiv_type);
+ if (!high_positive)
+ {
+ high_positive = TYPE_MAX_VALUE (type);
+ if (!high_positive)
+ abort();
+ }
+ high_positive = fold (build (RSHIFT_EXPR, type,
+ convert (type, high_positive),
+ convert (type, integer_one_node)));
+
+ /* If the low bound is specified, "and" the range with the
+ range for which the original unsigned value will be
+ positive. */
+ if (low != 0)
+ {
+ if (! merge_ranges (&n_in_p, &n_low, &n_high,
+ 1, n_low, n_high,
+ 1, convert (type, integer_zero_node),
+ high_positive))
+ break;
+
+ in_p = (n_in_p == in_p);
+ }
+ else
+ {
+ /* Otherwise, "or" the range with the range of the input
+ that will be interpreted as negative. */
+ if (! merge_ranges (&n_in_p, &n_low, &n_high,
+ 0, n_low, n_high,
+ 1, convert (type, integer_zero_node),
+ high_positive))
+ break;
+
+ in_p = (in_p != n_in_p);
+ }
+ }
+
+ exp = arg0;
+ low = n_low, high = n_high;
+ continue;
+
+ default:
+ break;
+ }
+
+ break;
+ }
-static int
-simple_operand_p (exp)
- tree exp;
-{
- /* Strip any conversions that don't change the machine mode. */
- while ((TREE_CODE (exp) == NOP_EXPR
- || TREE_CODE (exp) == CONVERT_EXPR)
- && (TYPE_MODE (TREE_TYPE (exp))
- == TYPE_MODE (TREE_TYPE (TREE_OPERAND (exp, 0)))))
- exp = TREE_OPERAND (exp, 0);
+ /* If EXP is a constant, we can evaluate whether this is true or false. */
+ if (TREE_CODE (exp) == INTEGER_CST)
+ {
+ in_p = in_p == (integer_onep (range_binop (GE_EXPR, integer_type_node,
+ exp, 0, low, 0))
+ && integer_onep (range_binop (LE_EXPR, integer_type_node,
+ exp, 1, high, 1)));
+ low = high = 0;
+ exp = 0;
+ }
- return (TREE_CODE_CLASS (TREE_CODE (exp)) == 'c'
- || (TREE_CODE_CLASS (TREE_CODE (exp)) == 'd'
- && ! TREE_ADDRESSABLE (exp)
- && ! TREE_THIS_VOLATILE (exp)
- && ! DECL_NONLOCAL (exp)
- /* Don't regard global variables as simple. They may be
- allocated in ways unknown to the compiler (shared memory,
- #pragma weak, etc). */
- && ! TREE_PUBLIC (exp)
- && ! DECL_EXTERNAL (exp)
- /* Loading a static variable is unduly expensive, but global
- registers aren't expensive. */
- && (! TREE_STATIC (exp) || DECL_REGISTER (exp))));
+ *pin_p = in_p, *plow = low, *phigh = high;
+ return exp;
}
\f
-/* Subroutine for fold_truthop: try to optimize a range test.
+/* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result
+ type, TYPE, return an expression to test if EXP is in (or out of, depending
+ on IN_P) the range. */
- For example, "i >= 2 && i =< 9" can be done as "(unsigned) (i - 2) <= 7".
+static tree
+build_range_check (type, exp, in_p, low, high)
+ tree type;
+ tree exp;
+ int in_p;
+ tree low, high;
+{
+ tree etype = TREE_TYPE (exp);
+ tree utype, value;
- JCODE is the logical combination of the two terms. It is TRUTH_AND_EXPR
- (representing TRUTH_ANDIF_EXPR and TRUTH_AND_EXPR) or TRUTH_OR_EXPR
- (representing TRUTH_ORIF_EXPR and TRUTH_OR_EXPR). TYPE is the type of
- the result.
+ if (! in_p
+ && (0 != (value = build_range_check (type, exp, 1, low, high))))
+ return invert_truthvalue (value);
- VAR is the value being tested. LO_CODE and HI_CODE are the comparison
- operators comparing VAR to LO_CST and HI_CST. LO_CST is known to be no
- larger than HI_CST (they may be equal).
+ else if (low == 0 && high == 0)
+ return convert (type, integer_one_node);
- We return the simplified tree or 0 if no optimization is possible. */
+ else if (low == 0)
+ return fold (build (LE_EXPR, type, exp, high));
-static tree
-range_test (jcode, type, lo_code, hi_code, var, lo_cst, hi_cst)
- enum tree_code jcode, lo_code, hi_code;
- tree type, var, lo_cst, hi_cst;
-{
- tree utype;
- enum tree_code rcode;
+ else if (high == 0)
+ return fold (build (GE_EXPR, type, exp, low));
+
+ else if (operand_equal_p (low, high, 0))
+ return fold (build (EQ_EXPR, type, exp, low));
- /* See if this is a range test and normalize the constant terms. */
+ else if (TREE_UNSIGNED (etype) && integer_zerop (low))
+ return build_range_check (type, exp, 1, 0, high);
- if (jcode == TRUTH_AND_EXPR)
+ else if (integer_zerop (low))
{
- switch (lo_code)
- {
- case NE_EXPR:
- /* See if we have VAR != CST && VAR != CST+1. */
- if (! (hi_code == NE_EXPR
- && TREE_INT_CST_LOW (hi_cst) - TREE_INT_CST_LOW (lo_cst) == 1
- && tree_int_cst_equal (integer_one_node,
- const_binop (MINUS_EXPR,
- hi_cst, lo_cst, 0))))
- return 0;
+ utype = unsigned_type (etype);
+ return build_range_check (type, convert (utype, exp), 1, 0,
+ convert (utype, high));
+ }
- rcode = GT_EXPR;
- break;
+ else if (0 != (value = const_binop (MINUS_EXPR, high, low, 0))
+ && ! TREE_OVERFLOW (value))
+ return build_range_check (type,
+ fold (build (MINUS_EXPR, etype, exp, low)),
+ 1, convert (etype, integer_zero_node), value);
+ else
+ return 0;
+}
+\f
+/* Given two ranges, see if we can merge them into one. Return 1 if we
+ can, 0 if we can't. Set the output range into the specified parameters. */
- case GT_EXPR:
- case GE_EXPR:
- if (hi_code == LT_EXPR)
- hi_cst = const_binop (MINUS_EXPR, hi_cst, integer_one_node, 0);
- else if (hi_code != LE_EXPR)
- return 0;
+static int
+merge_ranges (pin_p, plow, phigh, in0_p, low0, high0, in1_p, low1, high1)
+ int *pin_p;
+ tree *plow, *phigh;
+ int in0_p, in1_p;
+ tree low0, high0, low1, high1;
+{
+ int no_overlap;
+ int subset;
+ int temp;
+ tree tem;
+ int in_p;
+ tree low, high;
+ int lowequal = ((low0 == 0 && low1 == 0)
+ || integer_onep (range_binop (EQ_EXPR, integer_type_node,
+ low0, 0, low1, 0)));
+ int highequal = ((high0 == 0 && high1 == 0)
+ || integer_onep (range_binop (EQ_EXPR, integer_type_node,
+ high0, 1, high1, 1)));
+
+ /* Make range 0 be the range that starts first, or ends last if they
+ start at the same value. Swap them if it isn't. */
+ if (integer_onep (range_binop (GT_EXPR, integer_type_node,
+ low0, 0, low1, 0))
+ || (lowequal
+ && integer_onep (range_binop (GT_EXPR, integer_type_node,
+ high1, 1, high0, 1))))
+ {
+ temp = in0_p, in0_p = in1_p, in1_p = temp;
+ tem = low0, low0 = low1, low1 = tem;
+ tem = high0, high0 = high1, high1 = tem;
+ }
- if (lo_code == GT_EXPR)
- lo_cst = const_binop (PLUS_EXPR, lo_cst, integer_one_node, 0);
+ /* Now flag two cases, whether the ranges are disjoint or whether the
+ second range is totally subsumed in the first. Note that the tests
+ below are simplified by the ones above. */
+ no_overlap = integer_onep (range_binop (LT_EXPR, integer_type_node,
+ high0, 1, low1, 0));
+ subset = integer_onep (range_binop (LE_EXPR, integer_type_node,
+ high1, 1, high0, 1));
+
+ /* We now have four cases, depending on whether we are including or
+ excluding the two ranges. */
+ if (in0_p && in1_p)
+ {
+ /* If they don't overlap, the result is false. If the second range
+ is a subset it is the result. Otherwise, the range is from the start
+ of the second to the end of the first. */
+ if (no_overlap)
+ in_p = 0, low = high = 0;
+ else if (subset)
+ in_p = 1, low = low1, high = high1;
+ else
+ in_p = 1, low = low1, high = high0;
+ }
- /* We now have VAR >= LO_CST && VAR <= HI_CST. */
- rcode = LE_EXPR;
- break;
+ else if (in0_p && ! in1_p)
+ {
+ /* If they don't overlap, the result is the first range. If they are
+ equal, the result is false. If the second range is a subset of the
+ first, and the ranges begin at the same place, we go from just after
+ the end of the first range to the end of the second. If the second
+ range is not a subset of the first, or if it is a subset and both
+ ranges end at the same place, the range starts at the start of the
+ first range and ends just before the second range.
+ Otherwise, we can't describe this as a single range. */
+ if (no_overlap)
+ in_p = 1, low = low0, high = high0;
+ else if (lowequal && highequal)
+ in_p = 0, low = high = 0;
+ else if (subset && lowequal)
+ {
+ in_p = 1, high = high0;
+ low = range_binop (PLUS_EXPR, NULL_TREE, high1, 0,
+ integer_one_node, 0);
+ }
+ else if (! subset || highequal)
+ {
+ in_p = 1, low = low0;
+ high = range_binop (MINUS_EXPR, NULL_TREE, low1, 0,
+ integer_one_node, 0);
+ }
+ else
+ return 0;
+ }
- default:
- return 0;
+ else if (! in0_p && in1_p)
+ {
+ /* If they don't overlap, the result is the second range. If the second
+ is a subset of the first, the result is false. Otherwise,
+ the range starts just after the first range and ends at the
+ end of the second. */
+ if (no_overlap)
+ in_p = 1, low = low1, high = high1;
+ else if (subset)
+ in_p = 0, low = high = 0;
+ else
+ {
+ in_p = 1, high = high1;
+ low = range_binop (PLUS_EXPR, NULL_TREE, high0, 1,
+ integer_one_node, 0);
}
}
+
else
{
- switch (lo_code)
+ /* The case where we are excluding both ranges. Here the complex case
+ is if they don't overlap. In that case, the only time we have a
+ range is if they are adjacent. If the second is a subset of the
+ first, the result is the first. Otherwise, the range to exclude
+ starts at the beginning of the first range and ends at the end of the
+ second. */
+ if (no_overlap)
{
- case EQ_EXPR:
- /* See if we have VAR == CST || VAR == CST+1. */
- if (! (hi_code == EQ_EXPR
- && TREE_INT_CST_LOW (hi_cst) - TREE_INT_CST_LOW (lo_cst) == 1
- && tree_int_cst_equal (integer_one_node,
- const_binop (MINUS_EXPR,
- hi_cst, lo_cst, 0))))
- return 0;
-
- rcode = LE_EXPR;
- break;
-
- case LE_EXPR:
- case LT_EXPR:
- if (hi_code == GE_EXPR)
- hi_cst = const_binop (MINUS_EXPR, hi_cst, integer_one_node, 0);
- else if (hi_code != GT_EXPR)
+ if (integer_onep (range_binop (EQ_EXPR, integer_type_node,
+ range_binop (PLUS_EXPR, NULL_TREE,
+ high0, 1,
+ integer_one_node, 1),
+ 1, low1, 0)))
+ in_p = 0, low = low0, high = high1;
+ else
return 0;
-
- if (lo_code == LE_EXPR)
- lo_cst = const_binop (PLUS_EXPR, lo_cst, integer_one_node, 0);
-
- /* We now have VAR < LO_CST || VAR > HI_CST. */
- rcode = GT_EXPR;
- break;
-
- default:
- return 0;
}
+ else if (subset)
+ in_p = 0, low = low0, high = high0;
+ else
+ in_p = 0, low = low0, high = high1;
}
- /* When normalizing, it is possible to both increment the smaller constant
- and decrement the larger constant. See if they are still ordered. */
- if (tree_int_cst_lt (hi_cst, lo_cst))
- return 0;
-
- /* Fail if VAR isn't an integer. */
- utype = TREE_TYPE (var);
- if (! INTEGRAL_TYPE_P (utype))
- return 0;
+ *pin_p = in_p, *plow = low, *phigh = high;
+ return 1;
+}
+\f
+/* EXP is some logical combination of boolean tests. See if we can
+ merge it into some range test. Return the new tree if so. */
- /* The range test is invalid if subtracting the two constants results
- in overflow. This can happen in traditional mode. */
- if (! int_fits_type_p (hi_cst, TREE_TYPE (var))
- || ! int_fits_type_p (lo_cst, TREE_TYPE (var)))
- return 0;
+static tree
+fold_range_test (exp)
+ tree exp;
+{
+ int or_op = (TREE_CODE (exp) == TRUTH_ORIF_EXPR
+ || TREE_CODE (exp) == TRUTH_OR_EXPR);
+ int in0_p, in1_p, in_p;
+ tree low0, low1, low, high0, high1, high;
+ tree lhs = make_range (TREE_OPERAND (exp, 0), &in0_p, &low0, &high0);
+ tree rhs = make_range (TREE_OPERAND (exp, 1), &in1_p, &low1, &high1);
+ tree tem;
- if (! TREE_UNSIGNED (utype))
+ /* If this is an OR operation, invert both sides; we will invert
+ again at the end. */
+ if (or_op)
+ in0_p = ! in0_p, in1_p = ! in1_p;
+
+ /* If both expressions are the same, if we can merge the ranges, and we
+ can build the range test, return it or it inverted. If one of the
+ ranges is always true or always false, consider it to be the same
+ expression as the other. */
+ if ((lhs == 0 || rhs == 0 || operand_equal_p (lhs, rhs, 0))
+ && merge_ranges (&in_p, &low, &high, in0_p, low0, high0,
+ in1_p, low1, high1)
+ && 0 != (tem = (build_range_check (TREE_TYPE (exp),
+ lhs != 0 ? lhs
+ : rhs != 0 ? rhs : integer_zero_node,
+ in_p, low, high))))
+ return or_op ? invert_truthvalue (tem) : tem;
+
+ /* On machines where the branch cost is expensive, if this is a
+ short-circuited branch and the underlying object on both sides
+ is the same, make a non-short-circuit operation. */
+ else if (BRANCH_COST >= 2
+ && (TREE_CODE (exp) == TRUTH_ANDIF_EXPR
+ || TREE_CODE (exp) == TRUTH_ORIF_EXPR)
+ && operand_equal_p (lhs, rhs, 0))
{
- utype = unsigned_type (utype);
- var = convert (utype, var);
- lo_cst = convert (utype, lo_cst);
- hi_cst = convert (utype, hi_cst);
+ /* If simple enough, just rewrite. Otherwise, make a SAVE_EXPR
+ unless we are at top level, in which case we can't do this. */
+ if (simple_operand_p (lhs))
+ return build (TREE_CODE (exp) == TRUTH_ANDIF_EXPR
+ ? TRUTH_AND_EXPR : TRUTH_OR_EXPR,
+ TREE_TYPE (exp), TREE_OPERAND (exp, 0),
+ TREE_OPERAND (exp, 1));
+
+ else if (current_function_decl != 0)
+ {
+ tree common = save_expr (lhs);
+
+ if (0 != (lhs = build_range_check (TREE_TYPE (exp), common,
+ or_op ? ! in0_p : in0_p,
+ low0, high0))
+ && (0 != (rhs = build_range_check (TREE_TYPE (exp), common,
+ or_op ? ! in1_p : in1_p,
+ low1, high1))))
+ return build (TREE_CODE (exp) == TRUTH_ANDIF_EXPR
+ ? TRUTH_AND_EXPR : TRUTH_OR_EXPR,
+ TREE_TYPE (exp), lhs, rhs);
+ }
}
- return fold (convert (type,
- build (rcode, utype,
- build (MINUS_EXPR, utype, var, lo_cst),
- const_binop (MINUS_EXPR, hi_cst, lo_cst, 0))));
+
+ return 0;
}
\f
/* Subroutine for fold_truthop: C is an INTEGER_CST interpreted as a P
- bit value. Arrange things so the extra bits will be set to zero if and]
- only if C is signed-extended to its full width. */
+ bit value. Arrange things so the extra bits will be set to zero if and
+ only if C is signed-extended to its full width. If MASK is nonzero,
+ it is an INTEGER_CST that should be AND'ed with the extra bits. */
static tree
-unextend (c, p, unsignedp)
+unextend (c, p, unsignedp, mask)
tree c;
int p;
int unsignedp;
+ tree mask;
{
tree type = TREE_TYPE (c);
int modesize = GET_MODE_BITSIZE (TYPE_MODE (type));
if (p == modesize || unsignedp)
return c;
- if (TREE_UNSIGNED (type))
- c = convert (signed_type (type), c);
-
/* We work by getting just the sign bit into the low-order bit, then
- into the high-order bit, then sign-extened. We then XOR that value
+ into the high-order bit, then sign-extend. We then XOR that value
with C. */
temp = const_binop (RSHIFT_EXPR, c, size_int (p - 1), 0);
temp = const_binop (BIT_AND_EXPR, temp, size_int (1), 0);
+
+ /* We must use a signed type in order to get an arithmetic right shift.
+ However, we must also avoid introducing accidental overflows, so that
+ a subsequent call to integer_zerop will work. Hence we must
+ do the type conversion here. At this point, the constant is either
+ zero or one, and the conversion to a signed type can never overflow.
+ We could get an overflow if this conversion is done anywhere else. */
+ if (TREE_UNSIGNED (type))
+ temp = convert (signed_type (type), temp);
+
temp = const_binop (LSHIFT_EXPR, temp, size_int (modesize - 1), 0);
temp = const_binop (RSHIFT_EXPR, temp, size_int (modesize - p - 1), 0);
+ if (mask != 0)
+ temp = const_binop (BIT_AND_EXPR, temp, convert (TREE_TYPE (c), mask), 0);
+ /* If necessary, convert the type back to match the type of C. */
+ if (TREE_UNSIGNED (type))
+ temp = convert (type, temp);
+
return convert (type, const_binop (BIT_XOR_EXPR, c, temp, 0));
}
\f
enum machine_mode ll_mode, lr_mode, rl_mode, rr_mode;
enum machine_mode lnmode, rnmode;
tree ll_mask, lr_mask, rl_mask, rr_mask;
+ tree ll_and_mask, lr_and_mask, rl_and_mask, rr_and_mask;
tree l_const, r_const;
tree type, result;
int first_bit, end_bit;
int volatilep;
- /* Start by getting the comparison codes and seeing if this looks like
- a range test. Fail if anything is volatile. If one operand is a
- BIT_AND_EXPR with the constant one, treat it as if it were surrounded
- with a NE_EXPR. */
+ /* Start by getting the comparison codes. Fail if anything is volatile.
+ If one operand is a BIT_AND_EXPR with the constant one, treat it as if
+ it were surrounded with a NE_EXPR. */
- if (TREE_SIDE_EFFECTS (lhs)
- || TREE_SIDE_EFFECTS (rhs))
+ if (TREE_SIDE_EFFECTS (lhs) || TREE_SIDE_EFFECTS (rhs))
return 0;
lcode = TREE_CODE (lhs);
if (rcode == BIT_AND_EXPR && integer_onep (TREE_OPERAND (rhs, 1)))
rcode = NE_EXPR, rhs = build (NE_EXPR, truth_type, rhs, integer_zero_node);
- if (TREE_CODE_CLASS (lcode) != '<'
- || TREE_CODE_CLASS (rcode) != '<')
+ if (TREE_CODE_CLASS (lcode) != '<' || TREE_CODE_CLASS (rcode) != '<')
return 0;
code = ((code == TRUTH_AND_EXPR || code == TRUTH_ANDIF_EXPR)
rl_arg = TREE_OPERAND (rhs, 0);
rr_arg = TREE_OPERAND (rhs, 1);
- if (TREE_CODE (lr_arg) == INTEGER_CST
- && TREE_CODE (rr_arg) == INTEGER_CST
- && operand_equal_p (ll_arg, rl_arg, 0))
- {
- if (tree_int_cst_lt (lr_arg, rr_arg))
- result = range_test (code, truth_type, lcode, rcode,
- ll_arg, lr_arg, rr_arg);
- else
- result = range_test (code, truth_type, rcode, lcode,
- ll_arg, rr_arg, lr_arg);
-
- /* If this isn't a range test, it also isn't a comparison that
- can be merged. However, it wins to evaluate the RHS unconditionally
- on machines with expensive branches. */
-
- if (result == 0 && BRANCH_COST >= 2)
- {
- if (TREE_CODE (ll_arg) != VAR_DECL
- && TREE_CODE (ll_arg) != PARM_DECL)
- {
- /* Avoid evaluating the variable part twice. */
- ll_arg = save_expr (ll_arg);
- lhs = build (lcode, TREE_TYPE (lhs), ll_arg, lr_arg);
- rhs = build (rcode, TREE_TYPE (rhs), ll_arg, rr_arg);
- }
- return build (code, truth_type, lhs, rhs);
- }
- return result;
- }
-
/* If the RHS can be evaluated unconditionally and its operands are
simple, it wins to evaluate the RHS unconditionally on machines
with expensive branches. In this case, this isn't a comparison
volatilep = 0;
ll_inner = decode_field_reference (ll_arg,
&ll_bitsize, &ll_bitpos, &ll_mode,
- &ll_unsignedp, &volatilep, &ll_mask);
+ &ll_unsignedp, &volatilep, &ll_mask,
+ &ll_and_mask);
lr_inner = decode_field_reference (lr_arg,
&lr_bitsize, &lr_bitpos, &lr_mode,
- &lr_unsignedp, &volatilep, &lr_mask);
+ &lr_unsignedp, &volatilep, &lr_mask,
+ &lr_and_mask);
rl_inner = decode_field_reference (rl_arg,
&rl_bitsize, &rl_bitpos, &rl_mode,
- &rl_unsignedp, &volatilep, &rl_mask);
+ &rl_unsignedp, &volatilep, &rl_mask,
+ &rl_and_mask);
rr_inner = decode_field_reference (rr_arg,
&rr_bitsize, &rr_bitpos, &rr_mode,
- &rr_unsignedp, &volatilep, &rr_mask);
+ &rr_unsignedp, &volatilep, &rr_mask,
+ &rr_and_mask);
/* It must be true that the inner operation on the lhs of each
comparison must be the same if we are to be able to do anything.
if (lcode != wanted_code)
{
if (l_const && integer_zerop (l_const) && integer_pow2p (ll_mask))
- l_const = ll_mask;
+ {
+ if (ll_unsignedp || tree_log2 (ll_mask) + 1 < ll_bitsize)
+ l_const = ll_mask;
+ else
+ /* Since ll_arg is a single bit bit mask, we can sign extend
+ it appropriately with a NEGATE_EXPR.
+ l_const is made a signed value here, but since for l_const != NULL
+ lr_unsignedp is not used, we don't need to clear the latter. */
+ l_const = fold (build1 (NEGATE_EXPR, TREE_TYPE (ll_arg),
+ convert (TREE_TYPE (ll_arg), ll_mask)));
+ }
else
return 0;
}
if (rcode != wanted_code)
{
if (r_const && integer_zerop (r_const) && integer_pow2p (rl_mask))
- r_const = rl_mask;
+ {
+ if (rl_unsignedp || tree_log2 (rl_mask) + 1 < rl_bitsize)
+ r_const = rl_mask;
+ else
+ /* This is analogous to the code for l_const above. */
+ r_const = fold (build1 (NEGATE_EXPR, TREE_TYPE (rl_arg),
+ convert (TREE_TYPE (rl_arg), rl_mask)));
+ }
else
return 0;
}
if (l_const)
{
- l_const = convert (type, unextend (l_const, ll_bitsize, ll_unsignedp));
+ l_const = convert (type, l_const);
+ l_const = unextend (l_const, ll_bitsize, ll_unsignedp, ll_and_mask);
l_const = const_binop (LSHIFT_EXPR, l_const, size_int (xll_bitpos), 0);
if (! integer_zerop (const_binop (BIT_AND_EXPR, l_const,
fold (build1 (BIT_NOT_EXPR,
}
if (r_const)
{
- r_const = convert (type, unextend (r_const, rl_bitsize, rl_unsignedp));
+ r_const = convert (type, r_const);
+ r_const = unextend (r_const, rl_bitsize, rl_unsignedp, rl_and_mask);
r_const = const_binop (LSHIFT_EXPR, r_const, size_int (xrl_bitpos), 0);
if (! integer_zerop (const_binop (BIT_AND_EXPR, r_const,
fold (build1 (BIT_NOT_EXPR,
tree t;
tree s;
{
- tree type = TREE_TYPE (t);
enum tree_code code = TREE_CODE (t);
/* See if this is the COMPOUND_EXPR we want to eliminate. */
return t;
}
\f
+/* Return a node which has the indicated constant VALUE (either 0 or
+ 1), and is of the indicated TYPE. */
+
+static tree
+constant_boolean_node (value, type)
+ int value;
+ tree type;
+{
+ if (type == integer_type_node)
+ return value ? integer_one_node : integer_zero_node;
+ else if (TREE_CODE (type) == BOOLEAN_TYPE)
+ return truthvalue_conversion (value ? integer_one_node :
+ integer_zero_node);
+ else
+ {
+ tree t = build_int_2 (value, 0);
+ TREE_TYPE (t) = type;
+ return t;
+ }
+}
+
/* Perform constant folding and related simplification of EXPR.
The related simplifications include x*1 => x, x*0 => 0, etc.,
and application of the associative law.
tree t1 = NULL_TREE;
tree tem;
tree type = TREE_TYPE (expr);
- register tree arg0, arg1;
+ register tree arg0 = NULL_TREE, arg1 = NULL_TREE;
register enum tree_code code = TREE_CODE (t);
register int kind;
int invert;
int wins = 1;
- /* Don't try to process an RTL_EXPR since its operands aren't trees. */
- if (code == RTL_EXPR)
+ /* Don't try to process an RTL_EXPR since its operands aren't trees.
+ Likewise for a SAVE_EXPR that's already been evaluated. */
+ if (code == RTL_EXPR || (code == SAVE_EXPR && SAVE_EXPR_RTL (t)) != 0)
return t;
/* Return right away if already constant. */
return build (COMPOUND_EXPR, type, TREE_OPERAND (arg1, 0),
fold (build (code, type,
arg0, TREE_OPERAND (arg1, 1))));
- else if (TREE_CODE (arg1) == COND_EXPR
- || TREE_CODE_CLASS (TREE_CODE (arg1)) == '<')
+ else if ((TREE_CODE (arg1) == COND_EXPR
+ || (TREE_CODE_CLASS (TREE_CODE (arg1)) == '<'
+ && TREE_CODE_CLASS (code) != '<'))
+ && (! TREE_SIDE_EFFECTS (arg0) || current_function_decl != 0))
{
tree test, true_value, false_value;
+ tree lhs = 0, rhs = 0;
if (TREE_CODE (arg1) == COND_EXPR)
{
}
else
{
+ tree testtype = TREE_TYPE (arg1);
test = arg1;
- true_value = integer_one_node;
- false_value = integer_zero_node;
+ true_value = convert (testtype, integer_one_node);
+ false_value = convert (testtype, integer_zero_node);
}
/* If ARG0 is complex we want to make sure we only evaluate
succeed in folding one part to a constant, we do not need
to make this SAVE_EXPR. Since we do this optimization
primarily to see if we do end up with constant and this
- SAVE_EXPR interfers with later optimizations, suppressing
- it when we can is important. */
+ SAVE_EXPR interferes with later optimizations, suppressing
+ it when we can is important.
+
+ If we are not in a function, we can't make a SAVE_EXPR, so don't
+ try to do so. Don't try to see if the result is a constant
+ if an arm is a COND_EXPR since we get exponential behavior
+ in that case. */
- if (TREE_CODE (arg0) != SAVE_EXPR
+ if (TREE_CODE (arg0) != SAVE_EXPR && ! TREE_CONSTANT (arg0)
+ && current_function_decl != 0
&& ((TREE_CODE (arg0) != VAR_DECL
&& TREE_CODE (arg0) != PARM_DECL)
|| TREE_SIDE_EFFECTS (arg0)))
{
- tree lhs = fold (build (code, type, arg0, true_value));
- tree rhs = fold (build (code, type, arg0, false_value));
+ if (TREE_CODE (true_value) != COND_EXPR)
+ lhs = fold (build (code, type, arg0, true_value));
- if (TREE_CONSTANT (lhs) || TREE_CONSTANT (rhs))
- return fold (build (COND_EXPR, type, test, lhs, rhs));
+ if (TREE_CODE (false_value) != COND_EXPR)
+ rhs = fold (build (code, type, arg0, false_value));
- arg0 = save_expr (arg0);
+ if ((lhs == 0 || ! TREE_CONSTANT (lhs))
+ && (rhs == 0 || !TREE_CONSTANT (rhs)))
+ arg0 = save_expr (arg0), lhs = rhs = 0;
}
- test = fold (build (COND_EXPR, type, test,
- fold (build (code, type, arg0, true_value)),
- fold (build (code, type, arg0, false_value))));
+ if (lhs == 0)
+ lhs = fold (build (code, type, arg0, true_value));
+ if (rhs == 0)
+ rhs = fold (build (code, type, arg0, false_value));
+
+ test = fold (build (COND_EXPR, type, test, lhs, rhs));
+
if (TREE_CODE (arg0) == SAVE_EXPR)
return build (COMPOUND_EXPR, type,
convert (void_type_node, arg0),
else if (TREE_CODE (arg0) == COMPOUND_EXPR)
return build (COMPOUND_EXPR, type, TREE_OPERAND (arg0, 0),
fold (build (code, type, TREE_OPERAND (arg0, 1), arg1)));
- else if (TREE_CODE (arg0) == COND_EXPR
- || TREE_CODE_CLASS (TREE_CODE (arg0)) == '<')
+ else if ((TREE_CODE (arg0) == COND_EXPR
+ || (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<'
+ && TREE_CODE_CLASS (code) != '<'))
+ && (! TREE_SIDE_EFFECTS (arg1) || current_function_decl != 0))
{
tree test, true_value, false_value;
+ tree lhs = 0, rhs = 0;
if (TREE_CODE (arg0) == COND_EXPR)
{
}
else
{
+ tree testtype = TREE_TYPE (arg0);
test = arg0;
- true_value = integer_one_node;
- false_value = integer_zero_node;
+ true_value = convert (testtype, integer_one_node);
+ false_value = convert (testtype, integer_zero_node);
}
- if (TREE_CODE (arg1) != SAVE_EXPR
+ if (TREE_CODE (arg1) != SAVE_EXPR && ! TREE_CONSTANT (arg0)
+ && current_function_decl != 0
&& ((TREE_CODE (arg1) != VAR_DECL
&& TREE_CODE (arg1) != PARM_DECL)
|| TREE_SIDE_EFFECTS (arg1)))
{
- tree lhs = fold (build (code, type, true_value, arg1));
- tree rhs = fold (build (code, type, false_value, arg1));
+ if (TREE_CODE (true_value) != COND_EXPR)
+ lhs = fold (build (code, type, true_value, arg1));
- if (TREE_CONSTANT (lhs) || TREE_CONSTANT (rhs)
- || TREE_CONSTANT (arg1))
- return fold (build (COND_EXPR, type, test, lhs, rhs));
+ if (TREE_CODE (false_value) != COND_EXPR)
+ rhs = fold (build (code, type, false_value, arg1));
- arg1 = save_expr (arg1);
+ if ((lhs == 0 || ! TREE_CONSTANT (lhs))
+ && (rhs == 0 || !TREE_CONSTANT (rhs)))
+ arg1 = save_expr (arg1), lhs = rhs = 0;
}
- test = fold (build (COND_EXPR, type, test,
- fold (build (code, type, true_value, arg1)),
- fold (build (code, type, false_value, arg1))));
+ if (lhs == 0)
+ lhs = fold (build (code, type, true_value, arg1));
+
+ if (rhs == 0)
+ rhs = fold (build (code, type, false_value, arg1));
+
+ test = fold (build (COND_EXPR, type, test, lhs, rhs));
if (TREE_CODE (arg1) == SAVE_EXPR)
return build (COMPOUND_EXPR, type,
convert (void_type_node, arg1),
float or both integer, we don't need the middle conversion if
it is wider than the final type and doesn't change the signedness
(for integers). Avoid this if the final type is a pointer
- since then we sometimes need the inner conversion. */
+ since then we sometimes need the inner conversion. Likewise if
+ the outer has a precision not equal to the size of its mode. */
if ((((inter_int || inter_ptr) && (inside_int || inside_ptr))
|| (inter_float && inside_float))
&& inter_prec >= inside_prec
&& (inter_float || inter_unsignedp == inside_unsignedp)
+ && ! (final_prec != GET_MODE_BITSIZE (TYPE_MODE (final_type))
+ && TYPE_MODE (final_type) == TYPE_MODE (inter_type))
&& ! final_ptr)
return convert (final_type, TREE_OPERAND (TREE_OPERAND (t, 0), 0));
+ /* If we have a sign-extension of a zero-extended value, we can
+ replace that by a single zero-extension. */
+ if (inside_int && inter_int && final_int
+ && inside_prec < inter_prec && inter_prec < final_prec
+ && inside_unsignedp && !inter_unsignedp)
+ return convert (final_type, TREE_OPERAND (TREE_OPERAND (t, 0), 0));
+
/* Two conversions in a row are not needed unless:
- some conversion is floating-point (overstrict for now), or
- the intermediate type is narrower than both initial and
&& ((inter_unsignedp && inter_prec > inside_prec)
== (final_unsignedp && final_prec > inter_prec))
&& ! (inside_ptr && inter_prec != final_prec)
- && ! (final_ptr && inside_prec != inter_prec))
+ && ! (final_ptr && inside_prec != inter_prec)
+ && ! (final_prec != GET_MODE_BITSIZE (TYPE_MODE (final_type))
+ && TYPE_MODE (final_type) == TYPE_MODE (inter_type))
+ && ! final_ptr)
return convert (final_type, TREE_OPERAND (TREE_OPERAND (t, 0), 0));
}
TREE_TYPE (t) = type;
TREE_OVERFLOW (t)
= (TREE_OVERFLOW (arg0)
- | force_fit_type (t, overflow));
+ | force_fit_type (t, overflow && !TREE_UNSIGNED (type)));
TREE_CONSTANT_OVERFLOW (t)
= TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg0);
}
else if (TREE_CODE (arg0) == REAL_CST)
t = build_real (type, REAL_VALUE_NEGATE (TREE_REAL_CST (arg0)));
- TREE_TYPE (t) = type;
}
else if (TREE_CODE (arg0) == NEGATE_EXPR)
return TREE_OPERAND (arg0, 0);
t = build_real (type,
REAL_VALUE_NEGATE (TREE_REAL_CST (arg0)));
}
- TREE_TYPE (t) = type;
}
else if (TREE_CODE (arg0) == ABS_EXPR || TREE_CODE (arg0) == NEGATE_EXPR)
return build1 (ABS_EXPR, type, TREE_OPERAND (arg0, 0));
TREE_TYPE (TREE_TYPE (arg0)),
TREE_OPERAND (arg0, 1))));
else if (TREE_CODE (arg0) == COMPLEX_CST)
- return build_complex (TREE_OPERAND (arg0, 0),
+ return build_complex (type, TREE_OPERAND (arg0, 0),
fold (build1 (NEGATE_EXPR,
TREE_TYPE (TREE_TYPE (arg0)),
TREE_OPERAND (arg0, 1))));
case BIT_NOT_EXPR:
if (wins)
{
- if (TREE_CODE (arg0) == INTEGER_CST)
- t = build_int_2 (~ TREE_INT_CST_LOW (arg0),
- ~ TREE_INT_CST_HIGH (arg0));
+ t = build_int_2 (~ TREE_INT_CST_LOW (arg0),
+ ~ TREE_INT_CST_HIGH (arg0));
TREE_TYPE (t) = type;
force_fit_type (t, 0);
TREE_OVERFLOW (t) = TREE_OVERFLOW (arg0);
{
/* The return value should always have
the same type as the original expression. */
- TREE_TYPE (t1) = TREE_TYPE (t);
+ if (TREE_TYPE (t1) != TREE_TYPE (t))
+ t1 = convert (TREE_TYPE (t), t1);
+
return t1;
}
return t;
if (real_onep (arg1))
return non_lvalue (convert (type, arg0));
/* x*2 is x+x */
- if (! wins && real_twop (arg1))
+ if (! wins && real_twop (arg1) && current_function_decl != 0)
{
tree arg = save_expr (arg0);
return build (PLUS_EXPR, type, arg, arg);
case BIT_IOR_EXPR:
bit_ior:
+ {
+ register enum tree_code code0, code1;
+
if (integer_all_onesp (arg1))
return omit_one_operand (type, arg1, arg0);
if (integer_zerop (arg1))
if (t1 != NULL_TREE)
return t1;
- /* (a << C1) | (a >> C2) if A is unsigned and C1+C2 is the size of A
+ /* (A << C1) | (A >> C2) if A is unsigned and C1+C2 is the size of A
is a rotate of A by C1 bits. */
+ /* (A << B) | (A >> (Z - B)) if A is unsigned and Z is the size of A
+ is a rotate of A by B bits. */
- if ((TREE_CODE (arg0) == RSHIFT_EXPR
- || TREE_CODE (arg0) == LSHIFT_EXPR)
- && (TREE_CODE (arg1) == RSHIFT_EXPR
- || TREE_CODE (arg1) == LSHIFT_EXPR)
- && TREE_CODE (arg0) != TREE_CODE (arg1)
+ code0 = TREE_CODE (arg0);
+ code1 = TREE_CODE (arg1);
+ if (((code0 == RSHIFT_EXPR && code1 == LSHIFT_EXPR)
+ || (code1 == RSHIFT_EXPR && code0 == LSHIFT_EXPR))
&& operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1,0), 0)
- && TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (arg0, 0)))
- && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
- && TREE_CODE (TREE_OPERAND (arg1, 1)) == INTEGER_CST
- && TREE_INT_CST_HIGH (TREE_OPERAND (arg0, 1)) == 0
- && TREE_INT_CST_HIGH (TREE_OPERAND (arg1, 1)) == 0
- && ((TREE_INT_CST_LOW (TREE_OPERAND (arg0, 1))
- + TREE_INT_CST_LOW (TREE_OPERAND (arg1, 1)))
+ && TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (arg0, 0))))
+ {
+ register tree tree01, tree11;
+ register enum tree_code code01, code11;
+
+ tree01 = TREE_OPERAND (arg0, 1);
+ tree11 = TREE_OPERAND (arg1, 1);
+ code01 = TREE_CODE (tree01);
+ code11 = TREE_CODE (tree11);
+ if (code01 == INTEGER_CST
+ && code11 == INTEGER_CST
+ && TREE_INT_CST_HIGH (tree01) == 0
+ && TREE_INT_CST_HIGH (tree11) == 0
+ && ((TREE_INT_CST_LOW (tree01) + TREE_INT_CST_LOW (tree11))
== TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0)))))
- return build (LROTATE_EXPR, type, TREE_OPERAND (arg0, 0),
- TREE_CODE (arg0) == LSHIFT_EXPR
- ? TREE_OPERAND (arg0, 1) : TREE_OPERAND (arg1, 1));
+ return build (LROTATE_EXPR, type, TREE_OPERAND (arg0, 0),
+ code0 == LSHIFT_EXPR ? tree01 : tree11);
+ else if (code11 == MINUS_EXPR
+ && TREE_CODE (TREE_OPERAND (tree11, 0)) == INTEGER_CST
+ && TREE_INT_CST_HIGH (TREE_OPERAND (tree11, 0)) == 0
+ && TREE_INT_CST_LOW (TREE_OPERAND (tree11, 0))
+ == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0)))
+ && operand_equal_p (tree01, TREE_OPERAND (tree11, 1), 0))
+ return build (code0 == LSHIFT_EXPR ? LROTATE_EXPR : RROTATE_EXPR,
+ type, TREE_OPERAND (arg0, 0), tree01);
+ else if (code01 == MINUS_EXPR
+ && TREE_CODE (TREE_OPERAND (tree01, 0)) == INTEGER_CST
+ && TREE_INT_CST_HIGH (TREE_OPERAND (tree01, 0)) == 0
+ && TREE_INT_CST_LOW (TREE_OPERAND (tree01, 0))
+ == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0)))
+ && operand_equal_p (tree11, TREE_OPERAND (tree01, 1), 0))
+ return build (code0 != LSHIFT_EXPR ? LROTATE_EXPR : RROTATE_EXPR,
+ type, TREE_OPERAND (arg0, 0), tree11);
+ }
goto associate;
+ }
case BIT_XOR_EXPR:
if (integer_zerop (arg1))
so only do this if -ffast-math. We can actually always safely
do it if ARG1 is a power of two, but it's hard to tell if it is
or not in a portable manner. */
- if (TREE_CODE (arg1) == REAL_CST && flag_fast_math
- && 0 != (tem = const_binop (code, build_real (type, dconst1),
- arg1, 0)))
- return fold (build (MULT_EXPR, type, arg0, tem));
-
+ if (TREE_CODE (arg1) == REAL_CST)
+ {
+ if (flag_fast_math
+ && 0 != (tem = const_binop (code, build_real (type, dconst1),
+ arg1, 0)))
+ return fold (build (MULT_EXPR, type, arg0, tem));
+ /* Find the reciprocal if optimizing and the result is exact. */
+ else if (optimize)
+ {
+ REAL_VALUE_TYPE r;
+ r = TREE_REAL_CST (arg1);
+ if (exact_real_inverse (TYPE_MODE(TREE_TYPE(arg0)), &r))
+ {
+ tem = build_real (type, r);
+ return fold (build (MULT_EXPR, type, arg0, tem));
+ }
+ }
+ }
goto binary;
case TRUNC_DIV_EXPR:
if (integer_zerop (arg1))
return t;
+ /* If arg0 is a multiple of arg1, then rewrite to the fastest div
+ operation, EXACT_DIV_EXPR.
+
+ Note that only CEIL_DIV_EXPR and FLOOR_DIV_EXPR are rewritten now.
+ At one time others generated faster code, it's not clear if they do
+ after the last round to changes to the DIV code in expmed.c. */
+ if ((code == CEIL_DIV_EXPR || code == FLOOR_DIV_EXPR)
+ && multiple_of_p (type, arg0, arg1))
+ return fold (build (EXACT_DIV_EXPR, type, arg0, arg1));
+
/* If we have ((a / C1) / C2) where both division are the same type, try
to simplify. First see if C1 * C2 overflows or not. */
if (TREE_CODE (arg0) == code && TREE_CODE (arg1) == INTEGER_CST
tree c2 = integer_zero_node;
tree xarg0 = arg0;
- if (TREE_CODE (xarg0) == SAVE_EXPR)
+ if (TREE_CODE (xarg0) == SAVE_EXPR && SAVE_EXPR_RTL (xarg0) == 0)
have_save_expr = 1, xarg0 = TREE_OPERAND (xarg0, 0);
STRIP_NOPS (xarg0);
+ /* Look inside the dividend and simplify using EXACT_DIV_EXPR
+ if possible. */
+ if (TREE_CODE (xarg0) == MULT_EXPR
+ && multiple_of_p (type, TREE_OPERAND (xarg0, 0), arg1))
+ {
+ tree t;
+
+ t = fold (build (MULT_EXPR, type,
+ fold (build (EXACT_DIV_EXPR, type,
+ TREE_OPERAND (xarg0, 0), arg1)),
+ TREE_OPERAND (xarg0, 1)));
+ if (have_save_expr)
+ t = save_expr (t);
+ return t;
+
+ }
+
+ if (TREE_CODE (xarg0) == MULT_EXPR
+ && multiple_of_p (type, TREE_OPERAND (xarg0, 1), arg1))
+ {
+ tree t;
+
+ t = fold (build (MULT_EXPR, type,
+ fold (build (EXACT_DIV_EXPR, type,
+ TREE_OPERAND (xarg0, 1), arg1)),
+ TREE_OPERAND (xarg0, 0)));
+ if (have_save_expr)
+ t = save_expr (t);
+ return t;
+ }
+
if (TREE_CODE (xarg0) == PLUS_EXPR
&& TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST)
c2 = TREE_OPERAND (xarg0, 1), xarg0 = TREE_OPERAND (xarg0, 0);
xarg0 = TREE_OPERAND (xarg0, 0);
}
- if (TREE_CODE (xarg0) == SAVE_EXPR)
+ if (TREE_CODE (xarg0) == SAVE_EXPR && SAVE_EXPR_RTL (xarg0) == 0)
have_save_expr = 1, xarg0 = TREE_OPERAND (xarg0, 0);
STRIP_NOPS (xarg0);
if (operand_equal_p (arg0, arg1, 0))
return arg0;
if (INTEGRAL_TYPE_P (type)
+ && TYPE_MAX_VALUE (type)
&& operand_equal_p (arg1, TYPE_MAX_VALUE (type), 1))
return omit_one_operand (type, arg1, arg0);
goto associate;
and its values must be 0 or 1.
("true" is a fixed value perhaps depending on the language,
but we don't handle values other than 1 correctly yet.) */
- return invert_truthvalue (arg0);
+ tem = invert_truthvalue (arg0);
+ /* Avoid infinite recursion. */
+ if (TREE_CODE (tem) == TRUTH_NOT_EXPR)
+ return t;
+ return convert (type, tem);
case TRUTH_ANDIF_EXPR:
/* Note that the operands of this must be ints
must be evaluated. */
if (integer_zerop (arg1))
return omit_one_operand (type, arg1, arg0);
+ /* Likewise for first arg, but note that only the TRUTH_AND_EXPR
+ case will be handled here. */
+ if (integer_zerop (arg0))
+ return omit_one_operand (type, arg0, arg1);
truth_andor:
/* We only do these simplifications if we are optimizing. */
to A || (B && C). Note that either operator can be any of the four
truth and/or operations and the transformation will still be
valid. Also note that we only care about order for the
- ANDIF and ORIF operators. */
+ ANDIF and ORIF operators. If B contains side effects, this
+ might change the truth-value of A. */
if (TREE_CODE (arg0) == TREE_CODE (arg1)
&& (TREE_CODE (arg0) == TRUTH_ANDIF_EXPR
|| TREE_CODE (arg0) == TRUTH_ORIF_EXPR
|| TREE_CODE (arg0) == TRUTH_AND_EXPR
- || TREE_CODE (arg0) == TRUTH_OR_EXPR))
+ || TREE_CODE (arg0) == TRUTH_OR_EXPR)
+ && ! TREE_SIDE_EFFECTS (TREE_OPERAND (arg0, 1)))
{
tree a00 = TREE_OPERAND (arg0, 0);
tree a01 = TREE_OPERAND (arg0, 1);
a01));
}
+ /* See if we can build a range comparison. */
+ if (0 != (tem = fold_range_test (t)))
+ return tem;
+
/* Check for the possibility of merging component references. If our
lhs is another similar operation, try to merge its rhs with our
rhs. Then try to merge our lhs and rhs. */
evaluate first arg. */
if (TREE_CODE (arg1) == INTEGER_CST && ! integer_zerop (arg1))
return omit_one_operand (type, arg1, arg0);
+ /* Likewise for first arg, but note this only occurs here for
+ TRUTH_OR_EXPR. */
+ if (TREE_CODE (arg0) == INTEGER_CST && ! integer_zerop (arg0))
+ return omit_one_operand (type, arg0, arg1);
goto truth_andor;
case TRUTH_XOR_EXPR:
First, see if one arg is constant; find the constant arg
and the other one. */
{
- tree constop = 0, varop;
+ tree constop = 0, varop = NULL_TREE;
int constopnum = -1;
if (TREE_CONSTANT (arg1))
if CONST+INCR overflows or if foo+incr might overflow.
This optimization is invalid for floating point due to rounding.
For pointer types we assume overflow doesn't happen. */
- if (TREE_CODE (TREE_TYPE (varop)) == POINTER_TYPE
+ if (POINTER_TYPE_P (TREE_TYPE (varop))
|| (! FLOAT_TYPE_P (TREE_TYPE (varop))
&& (code == EQ_EXPR || code == NE_EXPR)))
{
constop, TREE_OPERAND (varop, 1)));
TREE_SET_CODE (varop, PREINCREMENT_EXPR);
+ /* If VAROP is a reference to a bitfield, we must mask
+ the constant by the width of the field. */
+ if (TREE_CODE (TREE_OPERAND (varop, 0)) == COMPONENT_REF
+ && DECL_BIT_FIELD(TREE_OPERAND
+ (TREE_OPERAND (varop, 0), 1)))
+ {
+ int size
+ = TREE_INT_CST_LOW (DECL_SIZE
+ (TREE_OPERAND
+ (TREE_OPERAND (varop, 0), 1)));
+ tree mask, unsigned_type;
+ int precision;
+ tree folded_compare;
+
+ /* First check whether the comparison would come out
+ always the same. If we don't do that we would
+ change the meaning with the masking. */
+ if (constopnum == 0)
+ folded_compare = fold (build (code, type, constop,
+ TREE_OPERAND (varop, 0)));
+ else
+ folded_compare = fold (build (code, type,
+ TREE_OPERAND (varop, 0),
+ constop));
+ if (integer_zerop (folded_compare)
+ || integer_onep (folded_compare))
+ return omit_one_operand (type, folded_compare, varop);
+
+ unsigned_type = type_for_size (size, 1);
+ precision = TYPE_PRECISION (unsigned_type);
+ mask = build_int_2 (~0, ~0);
+ TREE_TYPE (mask) = unsigned_type;
+ force_fit_type (mask, 0);
+ mask = const_binop (RSHIFT_EXPR, mask,
+ size_int (precision - size), 0);
+ newconst = fold (build (BIT_AND_EXPR,
+ TREE_TYPE (varop), newconst,
+ convert (TREE_TYPE (varop),
+ mask)));
+ }
+
+
t = build (code, type, TREE_OPERAND (t, 0),
TREE_OPERAND (t, 1));
TREE_OPERAND (t, constopnum) = newconst;
}
else if (constop && TREE_CODE (varop) == POSTDECREMENT_EXPR)
{
- if (TREE_CODE (TREE_TYPE (varop)) == POINTER_TYPE
+ if (POINTER_TYPE_P (TREE_TYPE (varop))
|| (! FLOAT_TYPE_P (TREE_TYPE (varop))
&& (code == EQ_EXPR || code == NE_EXPR)))
{
= fold (build (MINUS_EXPR, TREE_TYPE (varop),
constop, TREE_OPERAND (varop, 1)));
TREE_SET_CODE (varop, PREDECREMENT_EXPR);
+
+ if (TREE_CODE (TREE_OPERAND (varop, 0)) == COMPONENT_REF
+ && DECL_BIT_FIELD(TREE_OPERAND
+ (TREE_OPERAND (varop, 0), 1)))
+ {
+ int size
+ = TREE_INT_CST_LOW (DECL_SIZE
+ (TREE_OPERAND
+ (TREE_OPERAND (varop, 0), 1)));
+ tree mask, unsigned_type;
+ int precision;
+ tree folded_compare;
+
+ if (constopnum == 0)
+ folded_compare = fold (build (code, type, constop,
+ TREE_OPERAND (varop, 0)));
+ else
+ folded_compare = fold (build (code, type,
+ TREE_OPERAND (varop, 0),
+ constop));
+ if (integer_zerop (folded_compare)
+ || integer_onep (folded_compare))
+ return omit_one_operand (type, folded_compare, varop);
+
+ unsigned_type = type_for_size (size, 1);
+ precision = TYPE_PRECISION (unsigned_type);
+ mask = build_int_2 (~0, ~0);
+ TREE_TYPE (mask) = TREE_TYPE (varop);
+ force_fit_type (mask, 0);
+ mask = const_binop (RSHIFT_EXPR, mask,
+ size_int (precision - size), 0);
+ newconst = fold (build (BIT_AND_EXPR,
+ TREE_TYPE (varop), newconst,
+ convert (TREE_TYPE (varop),
+ mask)));
+ }
+
+
t = build (code, type, TREE_OPERAND (t, 0),
TREE_OPERAND (t, 1));
TREE_OPERAND (t, constopnum) = newconst;
arg1 = const_binop (MINUS_EXPR, arg1, integer_one_node, 0);
t = build (code, type, TREE_OPERAND (t, 0), arg1);
break;
+
+ default:
+ break;
}
}
/* If this is an EQ or NE comparison with zero and ARG0 is
(1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
two operations, but the latter can be done in one less insn
- one machine that have only two-operand insns or on which a
+ on machines that have only two-operand insns or on which a
constant cannot be the first operand. */
if (integer_zerop (arg1) && (code == EQ_EXPR || code == NE_EXPR)
&& TREE_CODE (arg0) == BIT_AND_EXPR)
case GE_EXPR:
case LE_EXPR:
if (INTEGRAL_TYPE_P (TREE_TYPE (arg0)))
- {
- t = build_int_2 (1, 0);
- TREE_TYPE (t) = type;
- return t;
- }
+ return constant_boolean_node (1, type);
code = EQ_EXPR;
TREE_SET_CODE (t, code);
break;
/* For NE, we can only do this simplification if integer. */
if (! INTEGRAL_TYPE_P (TREE_TYPE (arg0)))
break;
- /* ... fall through ... */
+ /* ... fall through ... */
case GT_EXPR:
case LT_EXPR:
- t = build_int_2 (0, 0);
- TREE_TYPE (t) = type;
- return t;
+ return constant_boolean_node (0, type);
+ default:
+ abort ();
}
}
/* An unsigned comparison against 0 can be simplified. */
if (integer_zerop (arg1)
&& (INTEGRAL_TYPE_P (TREE_TYPE (arg1))
- || TREE_CODE (TREE_TYPE (arg1)) == POINTER_TYPE)
+ || POINTER_TYPE_P (TREE_TYPE (arg1)))
&& TREE_UNSIGNED (TREE_TYPE (arg1)))
{
switch (TREE_CODE (t))
return omit_one_operand (type,
convert (type, integer_zero_node),
arg0);
+ default:
+ break;
}
}
+ /* An unsigned <= 0x7fffffff can be simplified. */
+ {
+ int width = TYPE_PRECISION (TREE_TYPE (arg1));
+ if (TREE_CODE (arg1) == INTEGER_CST
+ && ! TREE_CONSTANT_OVERFLOW (arg1)
+ && width <= HOST_BITS_PER_WIDE_INT
+ && TREE_INT_CST_LOW (arg1) == ((HOST_WIDE_INT) 1 << (width - 1)) - 1
+ && TREE_INT_CST_HIGH (arg1) == 0
+ && (INTEGRAL_TYPE_P (TREE_TYPE (arg1))
+ || POINTER_TYPE_P (TREE_TYPE (arg1)))
+ && TREE_UNSIGNED (TREE_TYPE (arg1)))
+ {
+ switch (TREE_CODE (t))
+ {
+ case LE_EXPR:
+ return fold (build (GE_EXPR, type,
+ convert (signed_type (TREE_TYPE (arg0)),
+ arg0),
+ convert (signed_type (TREE_TYPE (arg1)),
+ integer_zero_node)));
+ case GT_EXPR:
+ return fold (build (LT_EXPR, type,
+ convert (signed_type (TREE_TYPE (arg0)),
+ arg0),
+ convert (signed_type (TREE_TYPE (arg1)),
+ integer_zero_node)));
+ default:
+ break;
+ }
+ }
+ }
+
/* If we are comparing an expression that just has comparisons
of two integer values, arithmetic expressions of those comparisons,
and constants, we can simplify it. There are only three cases
&& ! (TREE_CONSTANT (cval1) && TREE_CONSTANT (cval2))
&& TREE_TYPE (cval1) == TREE_TYPE (cval2)
&& INTEGRAL_TYPE_P (TREE_TYPE (cval1))
+ && TYPE_MAX_VALUE (TREE_TYPE (cval1))
+ && TYPE_MAX_VALUE (TREE_TYPE (cval2))
&& ! operand_equal_p (TYPE_MIN_VALUE (TREE_TYPE (cval1)),
TYPE_MAX_VALUE (TREE_TYPE (cval2)), 0))
{
/* If this is a comparison of a field, we may be able to simplify it. */
if ((TREE_CODE (arg0) == COMPONENT_REF
- || TREE_CODE (arg0) == BIT_FIELD_REF)
- && (code == EQ_EXPR || code == NE_EXPR)
- /* Handle the constant case even without -O
- to make sure the warnings are given. */
- && (optimize || TREE_CODE (arg1) == INTEGER_CST))
+ || TREE_CODE (arg0) == BIT_FIELD_REF)
+ && (code == EQ_EXPR || code == NE_EXPR)
+ /* Handle the constant case even without -O
+ to make sure the warnings are given. */
+ && (optimize || TREE_CODE (arg1) == INTEGER_CST))
{
t1 = optimize_bit_field_compare (code, type, arg0, arg1);
return t1 ? t1 : t;
0);
}
+#if 0 /* This is no longer useful, but breaks some real code. */
/* Assume a nonexplicit constant cannot equal an explicit one,
since such code would be undefined anyway.
Exception: on sysvr4, using #pragma weak,
&& TREE_CODE (arg0) == ADDR_EXPR
&& code == EQ_EXPR)
t1 = build_int_2 (0, 0);
-
+#endif
/* Two real constants can be compared explicitly. */
else if (TREE_CODE (arg0) == REAL_CST && TREE_CODE (arg1) == REAL_CST)
{
TREE_INT_CST_LOW (t1) ^= 1;
TREE_TYPE (t1) = type;
+ if (TREE_CODE (type) == BOOLEAN_TYPE)
+ return truthvalue_conversion (t1);
return t1;
case COND_EXPR:
case GE_EXPR:
case GT_EXPR:
return pedantic_non_lvalue
- (fold (build1 (ABS_EXPR, type, arg1)));
+ (convert (type, fold (build1 (ABS_EXPR,
+ TREE_TYPE (arg1), arg1))));
case LE_EXPR:
case LT_EXPR:
return pedantic_non_lvalue
(fold (build1 (NEGATE_EXPR, type,
- fold (build1 (ABS_EXPR, type, arg1)))));
+ convert (type,
+ fold (build1 (ABS_EXPR,
+ TREE_TYPE (arg1),
+ arg1))))));
+ default:
+ abort ();
}
/* If this is A != 0 ? A : 0, this is simply A. For ==, it is
return pedantic_non_lvalue (convert (type, arg1));
case LE_EXPR:
case LT_EXPR:
+ /* In C++ a ?: expression can be an lvalue, so put the
+ operand which will be used if they are equal first
+ so that we can convert this back to the
+ corresponding COND_EXPR. */
return pedantic_non_lvalue
(convert (type, (fold (build (MIN_EXPR, comp_type,
- comp_op0, comp_op1)))));
+ (comp_code == LE_EXPR
+ ? comp_op0 : comp_op1),
+ (comp_code == LE_EXPR
+ ? comp_op1 : comp_op0))))));
+ break;
case GE_EXPR:
case GT_EXPR:
return pedantic_non_lvalue
(convert (type, fold (build (MAX_EXPR, comp_type,
- comp_op0, comp_op1))));
+ (comp_code == GE_EXPR
+ ? comp_op0 : comp_op1),
+ (comp_code == GE_EXPR
+ ? comp_op1 : comp_op0)))));
+ break;
+ default:
+ abort ();
}
}
return pedantic_non_lvalue
(fold (build (MAX_EXPR, type, arg1, arg2)));
break;
+ case NE_EXPR:
+ break;
+ default:
+ abort ();
}
}
case COMPLEX_EXPR:
if (wins)
- return build_complex (arg0, arg1);
+ return build_complex (type, arg0, arg1);
return t;
case REALPART_EXPR:
/* Pull arithmetic ops out of the CLEANUP_POINT_EXPR where
appropriate. */
case CLEANUP_POINT_EXPR:
- if (! TREE_SIDE_EFFECTS (arg0))
- return convert (type, arg0);
+ if (! has_cleanups (arg0))
+ return TREE_OPERAND (t, 0);
{
enum tree_code code0 = TREE_CODE (arg0);
{
arg01 = TREE_OPERAND (arg0, 1);
- if (! TREE_SIDE_EFFECTS (arg00))
+ if (TREE_CONSTANT (arg00)
+ || ((code0 == TRUTH_ANDIF_EXPR || code0 == TRUTH_ORIF_EXPR)
+ && ! has_cleanups (arg00)))
return fold (build (code0, type, arg00,
fold (build1 (CLEANUP_POINT_EXPR,
TREE_TYPE (arg01), arg01))));
- if (! TREE_SIDE_EFFECTS (arg01))
+ if (TREE_CONSTANT (arg01))
return fold (build (code0, type,
fold (build1 (CLEANUP_POINT_EXPR,
TREE_TYPE (arg00), arg00)),
return t;
} /* switch (code) */
}
+
+/* Determine if first argument is a multiple of second argument.
+ Return 0 if it is not, or is not easily determined to so be.
+
+ An example of the sort of thing we care about (at this point --
+ this routine could surely be made more general, and expanded
+ to do what the *_DIV_EXPR's fold() cases do now) is discovering
+ that
+
+ SAVE_EXPR (I) * SAVE_EXPR (J * 8)
+
+ is a multiple of
+
+ SAVE_EXPR (J * 8)
+
+ when we know that the two `SAVE_EXPR (J * 8)' nodes are the
+ same node (which means they will have the same value at run
+ time, even though we don't know when they'll be assigned).
+
+ This code also handles discovering that
+
+ SAVE_EXPR (I) * SAVE_EXPR (J * 8)
+
+ is a multiple of
+
+ 8
+
+ (of course) so we don't have to worry about dealing with a
+ possible remainder.
+
+ Note that we _look_ inside a SAVE_EXPR only to determine
+ how it was calculated; it is not safe for fold() to do much
+ of anything else with the internals of a SAVE_EXPR, since
+ fold() cannot know when it will be evaluated at run time.
+ For example, the latter example above _cannot_ be implemented
+ as
+
+ SAVE_EXPR (I) * J
+
+ or any variant thereof, since the value of J at evaluation time
+ of the original SAVE_EXPR is not necessarily the same at the time
+ the new expression is evaluated. The only optimization of this
+ sort that would be valid is changing
+
+ SAVE_EXPR (I) * SAVE_EXPR (SAVE_EXPR (J) * 8)
+ divided by
+ 8
+
+ to
+
+ SAVE_EXPR (I) * SAVE_EXPR (J)
+
+ (where the same SAVE_EXPR (J) is used in the original and the
+ transformed version). */
+
+static int
+multiple_of_p (type, top, bottom)
+ tree type;
+ tree top;
+ tree bottom;
+{
+ if (operand_equal_p (top, bottom, 0))
+ return 1;
+
+ if (TREE_CODE (type) != INTEGER_TYPE)
+ return 0;
+
+ switch (TREE_CODE (top))
+ {
+ case MULT_EXPR:
+ return (multiple_of_p (type, TREE_OPERAND (top, 0), bottom)
+ || multiple_of_p (type, TREE_OPERAND (top, 1), bottom));
+
+ case PLUS_EXPR:
+ case MINUS_EXPR:
+ return (multiple_of_p (type, TREE_OPERAND (top, 0), bottom)
+ && multiple_of_p (type, TREE_OPERAND (top, 1), bottom));
+
+ case NOP_EXPR:
+ /* Punt if conversion from non-integral or wider integral type. */
+ if ((TREE_CODE (TREE_TYPE (TREE_OPERAND (top, 0))) != INTEGER_TYPE)
+ || (TYPE_PRECISION (type)
+ < TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (top, 0)))))
+ return 0;
+ /* Fall through. */
+ case SAVE_EXPR:
+ return multiple_of_p (type, TREE_OPERAND (top, 0), bottom);
+
+ case INTEGER_CST:
+ if ((TREE_CODE (bottom) != INTEGER_CST)
+ || (tree_int_cst_sgn (top) < 0)
+ || (tree_int_cst_sgn (bottom) < 0))
+ return 0;
+ return integer_zerop (const_binop (TRUNC_MOD_EXPR,
+ top, bottom, 0));
+
+ default:
+ return 0;
+ }
+}
+\f
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