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Re: free is a killer

On 10/29/13 00:38, Marc Glisse wrote:
On Mon, 28 Oct 2013, Jeff Law wrote:

On 10/28/13 16:05, Marc Glisse wrote:

I checked and it does the wrong thing (I don't have the testcase handy
anymore, but it shouldn't be hard to recreate one), I even wrote a patch
(attached) but it is related to:
so it can't go in. A more limited fix (still missing many cases) would
be possible. I didn't test VA_END, but it doesn't look as bad (it is the
SSA_NAME case that is wrong for memcpy
Actually, it's fairly easy to see with memset.  Something like this:

/* { dg-do compile } */
/* { dg-options "-O1 -fdump-tree-optimized" } */

void f (long *p) {
 *p = 42;
 p[4] = 42;
 __builtin_memset (p, 0, 100);

/* { dg-final { scan-tree-dump-not "= 42" "optimized" } } */
/* { dg-final { cleanup-tree-dump "optimized" } } */

Indeed. Do you want to commit it xfailed or put it in bugzilla so we
don't lose it? (it becomes harder if you replace p with p-1 in the
memset arguments).
BTW, you can get a VAR_DECL (and presumably a PARM_DECL) from ao_ref_base. Some of the ssa-dse tests show this.


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