-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
On 03/08/11 03:48, sankar chebolu wrote:
> foo (char *x)
> {
> char ret = *x;
>
> if (x)
> com();
> else
> bar();
> return ret;
> }
>
GCC 4.1 is insanely old and the optimizer may not have been working for
some reason. We don't really work on GCC 4.1 anymore.
Compiling your testcase with -O2 using GCC 4.5.1 I get:
.globl foo
.type foo, @function
foo:
.LFB0:
.cfi_startproc
pushq %rbx
.cfi_def_cfa_offset 16
.cfi_offset 3, -16
movsbl (%rdi), %ebx
xorl %eax, %eax
call com
movl %ebx, %eax
popq %rbx
.cfi_def_cfa_offset 8
ret
.cfi_endproc
.LFE0:
Clearly the null pointer check was eliminated.
jeff
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.11 (GNU/Linux)
Comment: Using GnuPG with Fedora - http://enigmail.mozdev.org/
iQEcBAEBAgAGBQJNdj0DAAoJEBRtltQi2kC7p5AH/33tN/amBk2yAIw1J6sxwvQP
1R1ckU3Q9Je5xt9QbRG7N3oooiiC+TE6SbeHmPSFSiJcyY86AkJmotlhzVx65dF1
jiYDsbTkIQsCHT1KofKm5QcAGFZdMUEafwt0hzlewRH6ZIc0cNogZGvg99OWTuPY
7izhSEXKRPxkhvnYJdxb7Wk3cPzt89V1xJzVZ8lJJek7HvjrDLq9EzYtkvHeBmN8
zV4rl4Sp0iIslQV3Y5gEDNJH+84GpZ8sNLRPoCNn+O7RRx+LWEzfc3oh+mddgFx/
G7Tk04SULkFLNK9fAdz3o5Oa+OtnZRvPiFyfS6qSWcHulRgm13hPNGwtQd17EKA=
=blOC
-----END PGP SIGNATURE-----
