[PATCH] pr13012: Support -fpcc-struct-return for x86-32

[John McCall]

On Jun 7, 2013, at 12:07 PM, Arthur O'Dwyer <arthur.j.odwyer at gmail.com> wrote:
> On Wed, Jun 5, 2013 at 1:23 PM, Arthur O'Dwyer
> <arthur.j.odwyer at gmail.com> wrote:
>> 
>>  This is my first post to cfe-commits, so my apologies if I get
>> something wrong.
>> A while back I filed an issue on Bugzilla requesting support for
>> -fpcc-struct-return:
>> http://llvm.org/bugs/show_bug.cgi?id=13012
>> 
>> Recently I wrote a real patch [...] I believe I don't have the necessary
>> credentials to commit the patch anyway, so basically I'm looking for
>> a patron to adopt this patch. :)
>> 
>> To observe what the patch does:
>>  echo "struct S {int i;} foo() {return (struct S){42};}" >foo.c
>>  clang -m32 -O3 -fomit-frame-pointer foo.c -S -o reg.s
>>  clang -m32 -O3 -fomit-frame-pointer foo.c -S -o pcc.s -fpcc-struct-return
>>  diff reg.s pcc.s
> 
> Ping? Any takers? Any comments at all?

I would really like to avoid adding support for all these little ABI-tweaking
options, and frankly, unless you're just being unassuming, it doesn't sound
like this is all that important to you.

ABI-changing options are also a Real Big Hammer for things like making
a couple assembly stubs have a slightly simpler CC.

John.