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tree-ssa-math-opts.c (find_bswap_or_nop): Zero out bytes in cmpxchg and cmpnop in two steps...

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2016-11-14  Thomas Preud'homme  <thomas.preudhomme@arm.com>

    gcc/
    * tree-ssa-math-opts.c (find_bswap_or_nop): Zero out bytes in cmpxchg
    and cmpnop in two steps: first the ones not accessed in original gimple
    expression in a endian independent way and then the ones not accessed
    in the final result in an endian-specific way.
    (bswap_replace): Stop doing big endian adjustment.

From-SVN: r242394
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Thomas Preud'homme 2016-11-14 18:55:05 +00:00 committed by Thomas Preud'homme
parent d32e1fd8b9
commit bf166718a9
2 changed files with 37 additions and 37 deletions
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8
gcc/ChangeLog
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@ -1,3 +1,11 @@
2016-11-14 Thomas Preud'homme <thomas.preudhomme@arm.com>
* tree-ssa-math-opts.c (find_bswap_or_nop): Zero out bytes in cmpxchg
and cmpnop in two steps: first the ones not accessed in original gimple
expression in a endian independent way and then the ones not accessed
in the final result in an endian-specific way.
(bswap_replace): Stop doing big endian adjustment.
2016-11-14 Uros Bizjak <ubizjak@gmail.com>
* config/i386/i386.md (*andndi3_doubleword): Merge operand constraints.

66
gcc/tree-ssa-math-opts.c
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@ -2504,9 +2504,11 @@ find_bswap_or_nop_1 (gimple *stmt, struct symbolic_number *n, int limit)
static gimple *
find_bswap_or_nop (gimple *stmt, struct symbolic_number *n, bool *bswap)
{
/* The number which the find_bswap_or_nop_1 result should match in order
to have a full byte swap. The number is shifted to the right
according to the size of the symbolic number before using it. */
unsigned rsize;
uint64_t tmpn, mask;
/* The number which the find_bswap_or_nop_1 result should match in order
to have a full byte swap. The number is shifted to the right
according to the size of the symbolic number before using it. */
uint64_t cmpxchg = CMPXCHG;
uint64_t cmpnop = CMPNOP;
@ -2527,28 +2529,38 @@ find_bswap_or_nop (gimple *stmt, struct symbolic_number *n, bool *bswap)
/* Find real size of result (highest non-zero byte). */
if (n->base_addr)
{
unsigned HOST_WIDE_INT rsize;
uint64_t tmpn;
for (tmpn = n->n, rsize = 0; tmpn; tmpn >>= BITS_PER_MARKER, rsize++);
else
rsize = n->range;
for (tmpn = n->n, rsize = 0; tmpn; tmpn >>= BITS_PER_MARKER, rsize++);
if (BYTES_BIG_ENDIAN && n->range != rsize)
/* This implies an offset, which is currently not handled by
bswap_replace. */
return NULL;
n->range = rsize;
}
/* Zero out the extra bits of N and CMP*. */
/* Zero out the bits corresponding to untouched bytes in original gimple
expression. */
if (n->range < (int) sizeof (int64_t))
{
uint64_t mask;
mask = ((uint64_t) 1 << (n->range * BITS_PER_MARKER)) - 1;
cmpxchg >>= (64 / BITS_PER_MARKER - n->range) * BITS_PER_MARKER;
cmpnop &= mask;
}
/* Zero out the bits corresponding to unused bytes in the result of the
gimple expression. */
if (rsize < n->range)
{
if (BYTES_BIG_ENDIAN)
{
mask = ((uint64_t) 1 << (rsize * BITS_PER_MARKER)) - 1;
cmpxchg &= mask;
cmpnop >>= (n->range - rsize) * BITS_PER_MARKER;
}
else
{
mask = ((uint64_t) 1 << (rsize * BITS_PER_MARKER)) - 1;
cmpxchg >>= (n->range - rsize) * BITS_PER_MARKER;
cmpnop &= mask;
}
n->range = rsize;
}
/* A complete byte swap should make the symbolic number to start with
the largest digit in the highest order byte. Unchanged symbolic
number indicates a read with same endianness as target architecture. */
@ -2636,26 +2648,6 @@ bswap_replace (gimple *cur_stmt, gimple *src_stmt, tree fndecl,
HOST_WIDE_INT load_offset = 0;
align = get_object_alignment (src);
/* If the new access is smaller than the original one, we need
to perform big endian adjustment. */
if (BYTES_BIG_ENDIAN)
{
HOST_WIDE_INT bitsize, bitpos;
machine_mode mode;
int unsignedp, reversep, volatilep;
tree offset;
get_inner_reference (src, &bitsize, &bitpos, &offset, &mode,
&unsignedp, &reversep, &volatilep);
if (n->range < (unsigned HOST_WIDE_INT) bitsize)
{
load_offset = (bitsize - n->range) / BITS_PER_UNIT;
unsigned HOST_WIDE_INT l
= (load_offset * BITS_PER_UNIT) & (align - 1);
if (l)
align = least_bit_hwi (l);
}
}
if (bswap
&& align < GET_MODE_ALIGNMENT (TYPE_MODE (load_type))