On 25/03/15 14:01, Marc Glisse wrote:
On Wed, 25 Mar 2015, Sebastian Huber wrote:
Hello,
I updated to GCC 5 and now it turns the RTEMS calloc() implementation
into
Disassembly of section .text:
00000000 <calloc>:
0: fb01 f000 mul.w r0, r1, r0
4: 2101 movs r1, #1
6: f7ff bffe b.w 0 <calloc>
a: bf00 nop
on ARM. How can I disable this optimization? I tried
__attribute__((__optimize__("-fno-builtin")))
void *calloc(
size_t nelem,
size_t elsize
)
{
char *cptr;
size_t length;
length = nelem * elsize;
cptr = malloc( length );
if ( cptr )
memset( cptr, '\0', length );
return cptr;
}
but this doesn't work. It this one of the -fno-tree-* options?
-fno-builtin is good, but you cannot use it in an optimize attribute.
This is quite confusing since for other optimiziations in this area it
works like that, e.g. glibc (include/libc-symbols.h):
/* Add the compiler optimization to inhibit loop transformation to library
calls. This is used to avoid recursive calls in memset and memmove
default implementations. */
#ifdef HAVE_CC_INHIBIT_LOOP_TO_LIBCALL
# define inhibit_loop_to_libcall \
__attribute__ ((__optimize__ ("-fno-tree-loop-distribute-patterns")))
#else
# define inhibit_loop_to_libcall
#endif
--
Sebastian Huber, embedded brains GmbH
Address : Dornierstr. 4, D-82178 Puchheim, Germany
Phone : +49 89 189 47 41-16
Fax : +49 89 189 47 41-09
E-Mail : sebastian.huber@xxxxxxxxxxxxxxxxxx
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