On Mon, Jun 23, 2025 at 5:41 AM Takayuki 'January June' Suwa
<jjsuwa_sys3...@yahoo.co.jp> wrote:
>
> On 2025/06/23 6:20, H.J. Lu wrote:
> > On Sun, Jun 22, 2025 at 9:54 PM Max Filippov <jcmvb...@gmail.com> wrote:
> >>
> >> On Sun, Jun 22, 2025 at 5:49 AM Takayuki 'January June' Suwa
> >> <jjsuwa_sys3...@yahoo.co.jp> wrote:
> >>>
> >>> On 2025/06/22 6:41, Max Filippov wrote:
> >>>> On Sat, Jun 21, 2025 at 2:12 PM Takayuki 'January June' Suwa
> >>>> <jjsuwa_sys3...@yahoo.co.jp> wrote:
> >>>>>
> >>>>> That hook has since been deprecated
> >>>>> (commit a670ebde3995481225ec62b29686ec07a21e5c10) and has led to
> >>>>> incorrect
> >>>>> results on Xtensa:
> >>>>>
> >>>>> /* example */
> >>>>> #define <stdint.h>
> >>>>> uint32_t __attribute__((noinline)) test0(uint32_t a, uint16_t b)
> >>>>> {
> >>>>> return a + b;
> >>>>> }
> >>>>> uint32_t __attribute__((noinline)) test1(uint32_t a, uint32_t b)
> >>>>> {
> >>>>> return test0(a, b);
> >>>>> }
> >>>>>
> >>>>> ;; before (-mabi=call0)
> >>>>> test0:
> >>>>> add.n a2, a3, a2
> >>>>> ret.n
> >>>>> test1:
> >>>>> sext a3, a3, 15 ;; NG, do not sign-extend
> >>>>> j.l test0, a9
> >>>>>
> >>>>> ;; after (-mabi=call0)
> >>>>> test0:
> >>>>> extui a3, a3, 0, 16 ;; OK
> >>>>> add.n a2, a3, a2
> >>>>> ret.n
> >>>>> test1:
> >>>>> j.l test0, a9
> >>>>>
> >>>>> With this patch, the result is consistent with other targets such as
> >>>>> AArch64.
> >>>>>
> >>>>> gcc/ChangeLog:
> >>>>>
> >>>>> * config/xtensa/xtensa.cc
> >>>>> (TARGET_PROMOTE_PROTOTYPES, TARGET_PROMOTE_FUNCTION_MODE):
> >>>>> Remove.
> >>>>> ---
> >>>>> gcc/config/xtensa/xtensa.cc | 5 -----
> >>>>> 1 file changed, 5 deletions(-)
> >>>>
> >>>> This results in a bunch of ICEs with the following backtrace:
> >>>>
> >>> How about leaving TARGET_PROMOTE_FUNCTION_MODE and just removing
> >>> TARGET_PROMOTE_PROTOTYPES?
> >
> > commit a670ebde3995481225ec62b29686ec07a21e5c10
> > Author: H.J. Lu <hjl.to...@gmail.com>
> > Date: Thu Nov 21 07:54:35 2024 +0800
> >
> > Drop targetm.promote_prototypes from C, C++ and Ada frontends
> >
> > dropped targetm.calls.promote_prototypes in FEs. But
> >
> > commit 78db4753c9646a372512e6a951fced12f74de0bc
> > Author: H.J. Lu <hjl.to...@gmail.com>
> > Date: Thu Nov 21 08:11:06 2024 +0800
> >
> > Honor TARGET_PROMOTE_PROTOTYPES during RTL expand
> >
> > used targetm.calls.promote_prototypes. TARGET_PROMOTE_PROTOTYPES
> > shouldn't be removed.
> >
> >> The sign extension of signed char function arguments is missing with
> >> this change,
> >> breaking the ABI, e.g
> >>
> >> void s8(signed char c);
> >> void cs8(signed char *c)
> >> {
> >> s8(*c);
> >> }
> >>
> >> is translated to
> >>
> >> cs8:
> >> entry sp, 32
> >> l8ui a10, a2, 0
> >> call8 s8
> >> retw.n
> >>
> >> --
> >> Thanks.
> >> -- Max
>
> Thank you for your attention to this issue. I will also withdraw my patch.
>
xtensa ABI requires sign extension of signed 8/16-bit arguments to 32
bits and zero extension of unsigned 8/16-bit arguments to 32 bits.
TARGET_PROMOTE_PROTOTYPES is an optimization, not an ABI requirement.
xtensa should remove TARGET_PROMOTE_PROTOTYPES and define
a proper TARGET_PROMOTE_FUNCTION_MODE, instead Please try this:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120888#c4
--
H.J.
