Redundant malloc in structure optimization? (testsuite/gcc.dg/struct/wo_prof_global_var.c)

[Richard Guenther]

On Thu, May 1, 2008 at 2:19 PM, Olga Golovanevsky <OLGA@il.ibm.com> wrote:
>
>
>  gcc-owner@gcc.gnu.org wrote on 28/04/2008 12:36:44:
>
>
>  > Hello,
>  > I am looking at a testsuite failure (wo_prof_global_var.c) in my
>  > porting. Somehow, I found GCC 4.3.0 seems to generate unnecessary malloc
>  > during structure optimization. In the code, the structure is split into
>  > two individual fields (D.2240 and D.2242) and they are allocated
>  > separately. But the original structure (D.2215) is still allocated, and
>  > not used afterward.  The following RTL-level optimization cannot
>  > eliminate it.
>
>  I think that p is global, and in my understanding right now we have no
>  whole
>  program dead code elimination optimization in gcc, but may be I am wrong.

You cannot remove p, but if you could split up the allocation for *p then you
can for sure remove the original allocation for *p.  Otherwise you generated
wrong code in the first place, which you certainly did, if p was global.

Richard.