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Re: [Qemu-devel] [PATCH v2 02/20] include/fpu/softfloat: remove USE_SOFT
From: |
Richard Henderson |
Subject: |
Re: [Qemu-devel] [PATCH v2 02/20] include/fpu/softfloat: remove USE_SOFTFLOAT_STRUCT_TYPES |
Date: |
Tue, 9 Jan 2018 08:45:27 -0800 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.5.0 |
On 01/09/2018 06:43 AM, Peter Maydell wrote:
> On 9 January 2018 at 14:20, Laurent Vivier <address@hidden> wrote:
>> Le 09/01/2018 à 15:14, Peter Maydell a écrit :
>>> Is gcc's codegen still bad enough that we have to default to not
>>> using the type-checking versions? If so, maybe we could at least
>>> enable the type-checking on an --enable-debug build, so it doesn't
>>> bitrot all the time.
>>
>> What means "bad enough"? for some targets it works fine.
>
> I mean whatever the problem was that made us write the comment
> A sufficiently clever compiler and
> sane ABI should be able to see though these structs. However
> x86/gcc 3.x seems to struggle a bit, so leave them disabled by default.
E.g. the i386 ABI is *not* sane in this respect. Nor is sparcv8plus. I'd have
to check on the others.
If we enable USE_SOFTFLOAT_STRUCT_TYPES, then we *must* remove the markup for
f32 and f64 from include/exec/helper-head.h, because structures are passed
differently from integers as parameters and/or return values.
I personally do not think USE_SOFTFLOAT_STRUCT_TYPES is worth the headache.
r~
[Qemu-devel] [PATCH v2 05/20] include/fpu/softfloat: implement float16_set_sign helper, Alex Bennée, 2018/01/09
[Qemu-devel] [PATCH v2 03/20] include/fpu/softfloat: implement float16_abs helper, Alex Bennée, 2018/01/09
[Qemu-devel] [PATCH v2 06/20] include/fpu/softfloat: add some float16 constants, Alex Bennée, 2018/01/09
[Qemu-devel] [PATCH v2 04/20] include/fpu/softfloat: implement float16_chs helper, Alex Bennée, 2018/01/09