>From one of the test cases from
http://embed.cs.utah.edu/embarrassing/dec_09/harvest/gcc-head_llvm-gcc-head/
typedef unsigned int size_t;
typedef unsigned char apr_byte_t;
typedef unsigned long long apr_uint64_t;
struct _SHA512_CTX
{
apr_uint64_t state[8];
apr_uint64_t bitcount[2];
apr_byte_t buffer[128];
};
typedef struct _SHA512_CTX SHA512_CTX;
typedef apr_byte_t sha2_byte;
typedef apr_uint64_t sha2_word64;
/* compiler builtin:
unsigned int __builtin_object_size(void * , int ) ; */
/* compiler builtin:
void *__builtin___memset_chk(void * , int , unsigned int , unsigned int )
; */
extern __attribute__ ((__nothrow__, __noreturn__))
void __assert_fail (char const *__assertion,
char const *__file,
unsigned int __line, char const *__function);
void apr__SHA512_Final (apr_byte_t * digest, SHA512_CTX * context);
void apr__SHA512_Last (SHA512_CTX * context);
void apr__SHA512_Last (SHA512_CTX * context);
void apr__SHA512_Final (apr_byte_t * digest, SHA512_CTX * context)
{
sha2_word64 *d;
int j;
sha2_word64 tmp;
sha2_word64 *tmp___0;
void __attribute__ ((__artificial__)) * _cil_inline_tmp_228;
void *_cil_inline_tmp_229;
int _cil_inline_tmp_230;
size_t _cil_inline_tmp_231;
unsigned int _cil_inline_tmp_232;
void *_cil_inline_tmp_233;
{
d = (sha2_word64 *) digest;
if (!((unsigned int) context != (unsigned int) ((SHA512_CTX *) 0)))
{
__assert_fail ("context != (SHA512_CTX*)0", "random/unix/sha2.c",
870U, "apr__SHA512_Final");
}
if ((unsigned int) digest != (unsigned int) ((sha2_byte *) 0))
{
apr__SHA512_Last (context);
j = 0;
while (j < 8)
{
tmp = context->state[j];
tmp = (tmp >> 32) | (tmp << 32);
tmp =
((tmp & 0xff00ff00ff00ff00ULL) >> 8) |
((tmp & 71777214294589695ULL) << 8);
context->state[j] =
((tmp & 0xffff0000ffff0000ULL) >> 16) |
((tmp & 281470681808895ULL) << 16);
tmp___0 = d;
d++;
*tmp___0 = context->state[j];
j++;
}
}
_cil_inline_tmp_229 = (void *) context;
_cil_inline_tmp_230 = 0;
_cil_inline_tmp_231 = 4U;
_cil_inline_tmp_232 = __builtin_object_size ((void *) context, 0);
_cil_inline_tmp_233 =
__builtin___memset_chk ((void *) context, 0, 4U, _cil_inline_tmp_232);
_cil_inline_tmp_228 =
(void __attribute__ ((__artificial__)) *) _cil_inline_tmp_233;
return;
}
}
/* Checksum = D12A74A3 */
The 64bit gcc generates reasonable code (on par with LLVM with
-fno-reoder-blocks in code size). That includes using bswap for the open coded
endian
conversions
But with -m32 the code is much larger, mostly because bswap is never generated.
I played around with various options including -march=core -mtune=core2 -O2
etc.
but no bswap to be seen.
--
Summary: bswap optimization does not work for 32bit (but for
64bit)
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: enhancement
Priority: P3
Component: rtl-optimization
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: andi-gcc at firstfloor dot org
GCC host triplet: x86_64-linux
GCC target triplet: x86_64-linux
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42589
