Re: [Patch Arm] Fix PR 92999

[Richard Earnshaw <Richard.Earnshaw@foss.arm.com>]

On 10/11/2022 17:21, Richard Earnshaw via Gcc-patches wrote:
> 
> 
> On 08/11/2022 18:20, Ramana Radhakrishnan via Gcc-patches wrote:
>> PR92999 is a case where the VFP calling convention does not allocate
>> enough FP registers for a homogenous aggregate containing FP16 values.
>> I believe this is the complete fix but would appreciate another set of
>> eyes on this.
>>
>> Could I get a hand with a regression test run on an armhf environment
>> while I fix my environment ?
>>
>> gcc/ChangeLog:
>>
>> PR target/92999
>> *  config/arm/arm.c (aapcs_vfp_allocate_return_reg): Adjust to handle
>> aggregates with elements smaller than SFmode.
>>
>> gcc/testsuite/ChangeLog:
>>
>> * gcc.target/arm/pr92999.c: New test.
>>
>>
>> Thanks,
>> Ramana
>>
>> Signed-off-by: Ramana Radhakrishnan <ramana.gcc@gmail.com>
> 
> I'm not sure about this.  The AAPCS does not mention a base type of a 
> half-precision FP type as an appropriate homogeneous aggregate for using 
> VFP registers for either calling or returning.
> 
> So perhaps the bug is that we try to treat this as a homogeneous 
> aggregate at all.
> 
> R.

And clang seems to agree with my opinion: https://godbolt.org/z/ncaYfzebM

R.