Andrew Pinski <pins...@gmail.com> writes:
> On Sun, Mar 9, 2025 at 1:35 PM Andrew Pinski <quic_apin...@quicinc.com> wrote:
>>
>> LLVM folks noticed that GCC was shrink wrapping the call to
>> vector<int>::push_back.
>> So I thought it was a good idea to commit a testcase to make sure GCC does
>> not regress
>> in this area unknowning.
>>
>> Note the shrink wrapping started with r15-1619-g3b9b8d6cfdf593.
>> Note this enables the testcase for x86_64 (!ia32), powerpc, aarch64 and
>> riscv which I tested
>> via godbolt to see the shrink wrapping occurs. Also tested the testcase for
>> both
>> x86_64-linux-gnu and aarch64-linux-gnu to make sure I got the target selects
>> correct.
>
> Ping?
OK, thanks.
Richard
>
>>
>> Changes since v1:
>> * v2: Fix some comments typos that was mentioned in the bug report.
>>
>> PR rtl-optimization/118502
>>
>> gcc/testsuite/ChangeLog:
>>
>> * g++.dg/opt/shrink-wrapping-vector-1.C: New test.
>>
>> Signed-off-by: Andrew Pinski <quic_apin...@quicinc.com>
>> ---
>> .../g++.dg/opt/shrink-wrapping-vector-1.C | 17 +++++++++++++++++
>> 1 file changed, 17 insertions(+)
>> create mode 100644 gcc/testsuite/g++.dg/opt/shrink-wrapping-vector-1.C
>>
>> diff --git a/gcc/testsuite/g++.dg/opt/shrink-wrapping-vector-1.C
>> b/gcc/testsuite/g++.dg/opt/shrink-wrapping-vector-1.C
>> new file mode 100644
>> index 00000000000..8b1ad53fa80
>> --- /dev/null
>> +++ b/gcc/testsuite/g++.dg/opt/shrink-wrapping-vector-1.C
>> @@ -0,0 +1,17 @@
>> +// { dg-do compile { target { { { i?86-*-* x86_64-*-* } && { ! ia32 } } ||
>> { powerpc*-*-* aarch64*-*-* riscv*-*-* } } } }
>> +// { dg-options "-O2 -fdump-rtl-pro_and_epilogue" }
>> +// { dg-skip-if "requires hosted libstdc++ for vector" { ! hostedlib } }
>> +
>> +// PR rtl-optimization/118502
>> +
>> +// The shrink-wrapping should happen around the slow path of
>> vector<int>::push_back,
>> +// The fast path is just checking if there is enough space and doing a few
>> stores.
>> +// We want to verify that shrink wrapping always happens.
>> +
>> +#include <vector>
>> +
>> +void push_back(std::vector<int>& xs, unsigned char x) {
>> + xs.push_back(x);
>> +}
>> +
>> +/* { dg-final { scan-rtl-dump "Performing shrink-wrapping"
>> "pro_and_epilogue" } } */
>> --
>> 2.43.0
>>
