On Wed, Sep 28, 2016 at 5:23 PM, Yichao Yu <yyc1...@gmail.com> wrote: > Hi, > > I'd like to ask what should be the calling convention/ABI for these > routines on platforms with hardware floating point support (but > somehow still want to generate a libcall for whatever reasons). > > In particular, it seems that on all the platforms with a > arm*-*-gnueabihf triple I've checked (alarm armv7h, alarm armv6h, > debian armhf, fedora armv7hl) the __powidf2 function (and possibly > many others) are compiled with the AAPCS VFP calling convention, which > is also how it is used by gcc. However, LLVM dev (CC'd) claims that > these routines are meant to be always using soft floating point > calling convention even on platforms using hard floating point ABI. > > A breif google search doesn't show document supporting either so what > exactly should be used? Is it documented anywhere or what's the > default rule to decide the calling conventions for these functions? In > either case I think it's be nice if the document is a little more > explicit about this.
And see https://llvm.org/bugs/show_bug.cgi?id=30543 for some context. > > Yichao Yu
