On September 23, 2020 7:53:18 PM GMT+02:00, Jason Merrill <ja...@redhat.com>
wrote:
>On 9/23/20 4:14 AM, Richard Biener wrote:
>> C++ operator delete, when DECL_IS_REPLACEABLE_OPERATOR_DELETE_P,
>> does not cause the deleted object to be escaped. It also has no
>> other interesting side-effects for PTA so skip it like we do
>> for BUILT_IN_FREE.
>
>Hmm, this is true of the default implementation, but since the function
>
>is replaceable, we don't know what a user definition might do with the
>pointer.
But can the object still be 'used' after delete? Can delete fail / throw?
What guarantee does the predicate give us?
>> Bootstrapped and tested on x86_64-unknown-linux-gnu, pushed.
>>
>> Richard.
>>
>> 2020-09-23 Richard Biener <rguent...@suse.de>
>>
>> PR tree-optimization/97151
>> * tree-ssa-structalias.c (find_func_aliases_for_call):
>> DECL_IS_REPLACEABLE_OPERATOR_DELETE_P has no effect on
>> arguments.
>>
>> * g++.dg/cpp1y/new1.C: Adjust for two more handled transforms.
>> ---
>> gcc/testsuite/g++.dg/cpp1y/new1.C | 4 ++--
>> gcc/tree-ssa-structalias.c | 2 ++
>> 2 files changed, 4 insertions(+), 2 deletions(-)
>>
>> diff --git a/gcc/testsuite/g++.dg/cpp1y/new1.C
>b/gcc/testsuite/g++.dg/cpp1y/new1.C
>> index aa5f647d535..fec0088cb40 100644
>> --- a/gcc/testsuite/g++.dg/cpp1y/new1.C
>> +++ b/gcc/testsuite/g++.dg/cpp1y/new1.C
>> @@ -69,5 +69,5 @@ test_unused() {
>> delete p;
>> }
>>
>> -/* { dg-final { scan-tree-dump-times "Deleting : operator delete" 5
>"cddce1"} } */
>> -/* { dg-final { scan-tree-dump-times "Deleting : _\\d+ = operator
>new" 7 "cddce1"} } */
>> +/* { dg-final { scan-tree-dump-times "Deleting : operator delete" 6
>"cddce1"} } */
>> +/* { dg-final { scan-tree-dump-times "Deleting : _\\d+ = operator
>new" 8 "cddce1"} } */
>> diff --git a/gcc/tree-ssa-structalias.c b/gcc/tree-ssa-structalias.c
>> index 44fe52e0f65..f676bf91e95 100644
>> --- a/gcc/tree-ssa-structalias.c
>> +++ b/gcc/tree-ssa-structalias.c
>> @@ -4857,6 +4857,8 @@ find_func_aliases_for_call (struct function
>*fn, gcall *t)
>> point for reachable memory of their arguments. */
>> else if (flags & (ECF_PURE|ECF_LOOPING_CONST_OR_PURE))
>> handle_pure_call (t, &rhsc);
>> + else if (fndecl && DECL_IS_REPLACEABLE_OPERATOR_DELETE_P
>(fndecl))
>> + ;
>> else
>> handle_rhs_call (t, &rhsc);
>> if (gimple_call_lhs (t))
>>
