On Wed, Jun 18, 2014 at 6:55 AM, Thomas Preud'homme
<thomas.preudho...@arm.com> wrote:
>> From: Richard Biener [mailto:richard.guent...@gmail.com]
>> Sent: Wednesday, June 11, 2014 4:32 PM
>> >
>> >
>> > Is this OK for trunk? Does this bug qualify for a backport patch to
>> > 4.8 and 4.9 branches?
>>
>> This is ok for trunk and also for backporting (after a short while to
>> see if there is any fallout).
>
> Below is the backported patch for 4.8/4.9. Is this ok for both 4.8 and
> 4.9? If yes, how much more should I wait before committing?
>
> Tested on both 4.8 and 4.9 without regression in the testsuite after
> a bootstrap.
This is ok to commit now.
Thanks,
Richard.
> diff --git a/gcc/ChangeLog b/gcc/ChangeLog
> index 1e35bbe..0559b7f 100644
> --- a/gcc/ChangeLog
> +++ b/gcc/ChangeLog
> @@ -1,3 +1,16 @@
> +2014-06-12 Thomas Preud'homme <thomas.preudho...@arm.com>
> +
> + PR tree-optimization/61306
> + * tree-ssa-math-opts.c (struct symbolic_number): Store type of
> + expression instead of its size.
> + (do_shift_rotate): Adapt to change in struct symbolic_number. Return
> + false to prevent optimization when the result is unpredictable due to
> + arithmetic right shift of signed type with highest byte is set.
> + (verify_symbolic_number_p): Adapt to change in struct symbolic_number.
> + (find_bswap_1): Likewise. Return NULL to prevent optimization when the
> + result is unpredictable due to sign extension.
> + (find_bswap): Adapt to change in struct symbolic_number.
> +
> 2014-06-12 Alan Modra <amo...@gmail.com>
>
> PR target/61300
> diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
> index 757cb74..139f23c 100644
> --- a/gcc/testsuite/ChangeLog
> +++ b/gcc/testsuite/ChangeLog
> @@ -1,3 +1,9 @@
> +2014-06-12 Thomas Preud'homme <thomas.preudho...@arm.com>
> +
> + * gcc.c-torture/execute/pr61306-1.c: New test.
> + * gcc.c-torture/execute/pr61306-2.c: Likewise.
> + * gcc.c-torture/execute/pr61306-3.c: Likewise.
> +
> 2014-06-11 Richard Biener <rguent...@suse.de>
>
> PR tree-optimization/61452
> diff --git a/gcc/testsuite/gcc.c-torture/execute/pr61306-1.c
> b/gcc/testsuite/gcc.c-torture/execute/pr61306-1.c
> new file mode 100644
> index 0000000..ebc90a3
> --- /dev/null
> +++ b/gcc/testsuite/gcc.c-torture/execute/pr61306-1.c
> @@ -0,0 +1,39 @@
> +#ifdef __INT32_TYPE__
> +typedef __INT32_TYPE__ int32_t;
> +#else
> +typedef int int32_t;
> +#endif
> +
> +#ifdef __UINT32_TYPE__
> +typedef __UINT32_TYPE__ uint32_t;
> +#else
> +typedef unsigned uint32_t;
> +#endif
> +
> +#define __fake_const_swab32(x) ((uint32_t)( \
> + (((uint32_t)(x) & (uint32_t)0x000000ffUL) << 24) | \
> + (((uint32_t)(x) & (uint32_t)0x0000ff00UL) << 8) | \
> + (((uint32_t)(x) & (uint32_t)0x00ff0000UL) >> 8) | \
> + (( (int32_t)(x) & (int32_t)0xff000000UL) >> 24)))
> +
> +/* Previous version of bswap optimization failed to consider sign extension
> + and as a result would replace an expression *not* doing a bswap by a
> + bswap. */
> +
> +__attribute__ ((noinline, noclone)) uint32_t
> +fake_bswap32 (uint32_t in)
> +{
> + return __fake_const_swab32 (in);
> +}
> +
> +int
> +main(void)
> +{
> + if (sizeof (int32_t) * __CHAR_BIT__ != 32)
> + return 0;
> + if (sizeof (uint32_t) * __CHAR_BIT__ != 32)
> + return 0;
> + if (fake_bswap32 (0x87654321) != 0xffffff87)
> + __builtin_abort ();
> + return 0;
> +}
> diff --git a/gcc/testsuite/gcc.c-torture/execute/pr61306-2.c
> b/gcc/testsuite/gcc.c-torture/execute/pr61306-2.c
> new file mode 100644
> index 0000000..886ecfd
> --- /dev/null
> +++ b/gcc/testsuite/gcc.c-torture/execute/pr61306-2.c
> @@ -0,0 +1,40 @@
> +#ifdef __INT16_TYPE__
> +typedef __INT16_TYPE__ int16_t;
> +#else
> +typedef short int16_t;
> +#endif
> +
> +#ifdef __UINT32_TYPE__
> +typedef __UINT32_TYPE__ uint32_t;
> +#else
> +typedef unsigned uint32_t;
> +#endif
> +
> +#define __fake_const_swab32(x) ((uint32_t)( \
> + (((uint32_t) (x) & (uint32_t)0x000000ffUL) << 24) | \
> + (((uint32_t)(int16_t)(x) & (uint32_t)0x00ffff00UL) << 8) | \
> + (((uint32_t) (x) & (uint32_t)0x00ff0000UL) >> 8) | \
> + (((uint32_t) (x) & (uint32_t)0xff000000UL) >> 24)))
> +
> +
> +/* Previous version of bswap optimization failed to consider sign extension
> + and as a result would replace an expression *not* doing a bswap by a
> + bswap. */
> +
> +__attribute__ ((noinline, noclone)) uint32_t
> +fake_bswap32 (uint32_t in)
> +{
> + return __fake_const_swab32 (in);
> +}
> +
> +int
> +main(void)
> +{
> + if (sizeof (uint32_t) * __CHAR_BIT__ != 32)
> + return 0;
> + if (sizeof (int16_t) * __CHAR_BIT__ != 16)
> + return 0;
> + if (fake_bswap32 (0x81828384) != 0xff838281)
> + __builtin_abort ();
> + return 0;
> +}
> diff --git a/gcc/testsuite/gcc.c-torture/execute/pr61306-3.c
> b/gcc/testsuite/gcc.c-torture/execute/pr61306-3.c
> new file mode 100644
> index 0000000..6086e27
> --- /dev/null
> +++ b/gcc/testsuite/gcc.c-torture/execute/pr61306-3.c
> @@ -0,0 +1,13 @@
> +short a = -1;
> +int b;
> +char c;
> +
> +int
> +main ()
> +{
> + c = a;
> + b = a | c;
> + if (b != -1)
> + __builtin_abort ();
> + return 0;
> +}
> diff --git a/gcc/tree-ssa-math-opts.c b/gcc/tree-ssa-math-opts.c
> index 9ff857c..2b656ae 100644
> --- a/gcc/tree-ssa-math-opts.c
> +++ b/gcc/tree-ssa-math-opts.c
> @@ -1620,7 +1620,7 @@ make_pass_cse_sincos (gcc::context *ctxt)
>
> struct symbolic_number {
> unsigned HOST_WIDEST_INT n;
> - int size;
> + tree type;
> };
>
> /* Perform a SHIFT or ROTATE operation by COUNT bits on symbolic
> @@ -1632,13 +1632,15 @@ do_shift_rotate (enum tree_code code,
> struct symbolic_number *n,
> int count)
> {
> + int bitsize = TYPE_PRECISION (n->type);
> +
> if (count % 8 != 0)
> return false;
>
> /* Zero out the extra bits of N in order to avoid them being shifted
> into the significant bits. */
> - if (n->size < (int)sizeof (HOST_WIDEST_INT))
> - n->n &= ((unsigned HOST_WIDEST_INT)1 << (n->size * BITS_PER_UNIT)) - 1;
> + if (bitsize < 8 * (int)sizeof (HOST_WIDEST_INT))
> + n->n &= ((unsigned HOST_WIDEST_INT)1 << bitsize) - 1;
>
> switch (code)
> {
> @@ -1646,20 +1648,23 @@ do_shift_rotate (enum tree_code code,
> n->n <<= count;
> break;
> case RSHIFT_EXPR:
> + /* Arithmetic shift of signed type: result is dependent on the value.
> */
> + if (!TYPE_UNSIGNED (n->type) && (n->n & (0xff << (bitsize - 8))))
> + return false;
> n->n >>= count;
> break;
> case LROTATE_EXPR:
> - n->n = (n->n << count) | (n->n >> ((n->size * BITS_PER_UNIT) - count));
> + n->n = (n->n << count) | (n->n >> (bitsize - count));
> break;
> case RROTATE_EXPR:
> - n->n = (n->n >> count) | (n->n << ((n->size * BITS_PER_UNIT) - count));
> + n->n = (n->n >> count) | (n->n << (bitsize - count));
> break;
> default:
> return false;
> }
> /* Zero unused bits for size. */
> - if (n->size < (int)sizeof (HOST_WIDEST_INT))
> - n->n &= ((unsigned HOST_WIDEST_INT)1 << (n->size * BITS_PER_UNIT)) - 1;
> + if (bitsize < 8 * (int)sizeof (HOST_WIDEST_INT))
> + n->n &= ((unsigned HOST_WIDEST_INT)1 << bitsize) - 1;
> return true;
> }
>
> @@ -1676,7 +1681,7 @@ verify_symbolic_number_p (struct symbolic_number *n,
> gimple stmt)
> if (TREE_CODE (lhs_type) != INTEGER_TYPE)
> return false;
>
> - if (TYPE_PRECISION (lhs_type) != n->size * BITS_PER_UNIT)
> + if (TYPE_PRECISION (lhs_type) != TYPE_PRECISION (n->type))
> return false;
>
> return true;
> @@ -1733,20 +1738,23 @@ find_bswap_1 (gimple stmt, struct symbolic_number *n,
> int limit)
> to initialize the symbolic number. */
> if (!source_expr1)
> {
> + int size;
> +
> /* Set up the symbolic number N by setting each byte to a
> value between 1 and the byte size of rhs1. The highest
> order byte is set to n->size and the lowest order
> byte to 1. */
> - n->size = TYPE_PRECISION (TREE_TYPE (rhs1));
> - if (n->size % BITS_PER_UNIT != 0)
> + n->type = TREE_TYPE (rhs1);
> + size = TYPE_PRECISION (n->type);
> + if (size % BITS_PER_UNIT != 0)
> return NULL_TREE;
> - n->size /= BITS_PER_UNIT;
> + size /= BITS_PER_UNIT;
> n->n = (sizeof (HOST_WIDEST_INT) < 8 ? 0 :
> (unsigned HOST_WIDEST_INT)0x08070605 << 32 | 0x04030201);
>
> - if (n->size < (int)sizeof (HOST_WIDEST_INT))
> + if (size < (int)sizeof (HOST_WIDEST_INT))
> n->n &= ((unsigned HOST_WIDEST_INT)1 <<
> - (n->size * BITS_PER_UNIT)) - 1;
> + (size * BITS_PER_UNIT)) - 1;
>
> source_expr1 = rhs1;
> }
> @@ -1755,12 +1763,12 @@ find_bswap_1 (gimple stmt, struct symbolic_number *n,
> int limit)
> {
> case BIT_AND_EXPR:
> {
> - int i;
> + int i, size = TYPE_PRECISION (n->type) / BITS_PER_UNIT;
> unsigned HOST_WIDEST_INT val = widest_int_cst_value (rhs2);
> unsigned HOST_WIDEST_INT tmp = val;
>
> /* Only constants masking full bytes are allowed. */
> - for (i = 0; i < n->size; i++, tmp >>= BITS_PER_UNIT)
> + for (i = 0; i < size; i++, tmp >>= BITS_PER_UNIT)
> if ((tmp & 0xff) != 0 && (tmp & 0xff) != 0xff)
> return NULL_TREE;
>
> @@ -1776,19 +1784,28 @@ find_bswap_1 (gimple stmt, struct symbolic_number *n,
> int limit)
> break;
> CASE_CONVERT:
> {
> - int type_size;
> + int type_size, old_type_size;
> + tree type;
>
> - type_size = TYPE_PRECISION (gimple_expr_type (stmt));
> + type = gimple_expr_type (stmt);
> + type_size = TYPE_PRECISION (type);
> if (type_size % BITS_PER_UNIT != 0)
> return NULL_TREE;
>
> + /* Sign extension: result is dependent on the value. */
> + old_type_size = TYPE_PRECISION (n->type);
> + if (!TYPE_UNSIGNED (n->type)
> + && type_size > old_type_size
> + && n->n & (0xff << (old_type_size - 8)))
> + return NULL_TREE;
> +
> if (type_size / BITS_PER_UNIT < (int)(sizeof (HOST_WIDEST_INT)))
> {
> /* If STMT casts to a smaller type mask out the bits not
> belonging to the target type. */
> n->n &= ((unsigned HOST_WIDEST_INT)1 << type_size) - 1;
> }
> - n->size = type_size / BITS_PER_UNIT;
> + n->type = type;
> }
> break;
> default:
> @@ -1801,7 +1818,7 @@ find_bswap_1 (gimple stmt, struct symbolic_number *n,
> int limit)
>
> if (rhs_class == GIMPLE_BINARY_RHS)
> {
> - int i;
> + int i, size;
> struct symbolic_number n1, n2;
> unsigned HOST_WIDEST_INT mask;
> tree source_expr2;
> @@ -1825,11 +1842,12 @@ find_bswap_1 (gimple stmt, struct symbolic_number *n,
> int limit)
> source_expr2 = find_bswap_1 (rhs2_stmt, &n2, limit - 1);
>
> if (source_expr1 != source_expr2
> - || n1.size != n2.size)
> + || TYPE_PRECISION (n1.type) != TYPE_PRECISION (n2.type))
> return NULL_TREE;
>
> - n->size = n1.size;
> - for (i = 0, mask = 0xff; i < n->size; i++, mask <<= BITS_PER_UNIT)
> + n->type = n1.type;
> + size = TYPE_PRECISION (n->type) / BITS_PER_UNIT;
> + for (i = 0, mask = 0xff; i < size; i++, mask <<= BITS_PER_UNIT)
> {
> unsigned HOST_WIDEST_INT masked1, masked2;
>
> @@ -1868,7 +1886,7 @@ find_bswap (gimple stmt)
>
> struct symbolic_number n;
> tree source_expr;
> - int limit;
> + int limit, bitsize;
>
> /* The last parameter determines the depth search limit. It usually
> correlates directly to the number of bytes to be touched. We
> @@ -1883,13 +1901,14 @@ find_bswap (gimple stmt)
> return NULL_TREE;
>
> /* Zero out the extra bits of N and CMP. */
> - if (n.size < (int)sizeof (HOST_WIDEST_INT))
> + bitsize = TYPE_PRECISION (n.type);
> + if (bitsize < 8 * (int)sizeof (HOST_WIDEST_INT))
> {
> unsigned HOST_WIDEST_INT mask =
> - ((unsigned HOST_WIDEST_INT)1 << (n.size * BITS_PER_UNIT)) - 1;
> + ((unsigned HOST_WIDEST_INT)1 << bitsize) - 1;
>
> n.n &= mask;
> - cmp >>= (sizeof (HOST_WIDEST_INT) - n.size) * BITS_PER_UNIT;
> + cmp >>= sizeof (HOST_WIDEST_INT) * BITS_PER_UNIT - bitsize;
> }
>
> /* A complete byte swap should make the symbolic number to start
>
> Best regards,
>
> Thomas
>
>
