OpenE2K
/
gcc
2
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

re PR tree-optimization/67781 (wrong code generated on big-endian with -O1 -fexpensive-optimizations) 

2016-01-08  Thomas Preud'homme  <thomas.preudhomme@arm.com>

    gcc/
    PR tree-optimization/67781
    * 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.

    gcc/testsuite/
    PR tree-optimization/67781
    * gcc.c-torture/execute/pr67781.c: New file.

From-SVN: r232154
This commit is contained in:
Thomas Preud'homme 2016-01-08 09:21:19 +00:00 committed by Thomas Preud'homme
parent 262a363ff9
commit 80e9b3aaac
4 changed files with 73 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
gcc/ChangeLog
View File

@ -1,3 +1,11 @@
2016-01-08 Thomas Preud'homme <thomas.preudhomme@arm.com>
PR tree-optimization/67781
* 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.
2016-01-08 Jakub Jelinek <jakub@redhat.com>
PR tree-optimization/69083

5
gcc/testsuite/ChangeLog
View File

@ -1,3 +1,8 @@
2016-01-08 Thomas Preud'homme <thomas.preudhomme@arm.com>
PR tree-optimization/67781
* gcc.c-torture/execute/pr67781.c: New file.
2016-01-08 Jakub Jelinek <jakub@redhat.com>
PR tree-optimization/69083

34
gcc/testsuite/gcc.c-torture/execute/pr67781.c Normal file
View File

@ -0,0 +1,34 @@
#ifdef __UINT32_TYPE__
typedef __UINT32_TYPE__ uint32_t;
#else
typedef unsigned uint32_t;
#endif
#ifdef __UINT8_TYPE__
typedef __UINT8_TYPE__ uint8_t;
#else
typedef unsigned char uint8_t;
#endif
struct
{
uint32_t a;
uint8_t b;
} s = { 0x123456, 0x78 };
int pr67781()
{
uint32_t c = (s.a << 8) | s.b;
return c;
}
int
main ()
{
if (sizeof (uint32_t) * __CHAR_BIT__ != 32)
return 0;
if (pr67781 () != 0x12345678)
__builtin_abort ();
return 0;
}

36
gcc/tree-ssa-math-opts.c
View File

@ -2449,6 +2449,8 @@ 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)
{
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. */
@ -2472,24 +2474,38 @@ 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)
{
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++);
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. */