Hi,
On Thu, 13 Aug 2020 at 03:54, qiaopeixin <qiaopei...@huawei.com> wrote: > > Thanks for the review and commit. > > All the best, > Peixin > > -----Original Message----- > From: Richard Sandiford [mailto:richard.sandif...@arm.com] > Sent: 2020年8月13日 0:25 > To: qiaopeixin <qiaopei...@huawei.com> > Cc: gcc-patches@gcc.gnu.org > Subject: Re: [PATCH] AArch64: Add if condition in aarch64_function_value > [PR96479] > > qiaopeixin <qiaopei...@huawei.com> writes: > > Hi, > > > > The test case vector-subscript-2.c in the gcc testsuit will report an ICE > > in the expand pass since '-mgeneral-regs-only' is incompatible with the use > > of V4SI mode. I propose to report the diagnostic information instead of > > ICE, and the problem has been discussed on PR 96479. > > > > I attached the patch to solve the problem. Bootstrapped and tested on > > aarch64-linux-gnu. Any suggestions? > > Thanks, pushed. I was initially sceptical because raising an error here and > in aarch64_layout_arg is a hack. Both functions are just query functions and > shouldn't have any side effects. > > The approach we took for FP modes seemed better: we define the FP move > patterns unconditionally, and raise an error if we try to emit an FP move > with !TARGET_FLOAT. This defers any error reporting until we actually try to > generate code that depends on TARGET_FLOAT. > > But I guess SIMD stuff is different. There's no reason in principle why you > can't use: > > unsigned short __attribute__((vector_size(8))) > > *within* a function with -mgeneral-regs-only. It would just need to be > emulated, in the same way as for: > > unsigned short __attribute__((vector_size(4))) > > So it would be wrong to define the SIMD move patterns unconditionally and > raise an error there. > > So all in all, I agree this is the best we can do given the current > infrastructure. > Since this patch was committed my buildbot is broken for aarch64-linux-gnu because it now fails to build glibc-2.29: ../stdlib/bits/stdlib-float.h: In function 'atof': ../stdlib/bits/stdlib-float.h:26:1: error: '-mgeneral-regs-only' is incompatible with the use of floating-point types I haven't yet tried a more recent glibc version, not sure if 2.29 is considered obsolete? Christophe > Thanks, > Richard >
