On Tue, Apr 29, 2025 at 2:51 PM Liu, Hongtao <hongtao....@intel.com> wrote: > > > > > -----Original Message----- > > From: H.J. Lu <hjl.to...@gmail.com> > > Sent: Tuesday, April 29, 2025 1:58 PM > > To: Hongtao Liu <crazy...@gmail.com> > > Cc: GCC Patches <gcc-patches@gcc.gnu.org>; Uros Bizjak > > <ubiz...@gmail.com>; Liu, Hongtao <hongtao....@intel.com> > > Subject: Re: [PATCH] i386: Add > > ix86_expand_unsigned_small_int_cst_argument > > > > On Tue, Apr 29, 2025 at 1:54 PM H.J. Lu <hjl.to...@gmail.com> wrote: > > > > > > On Tue, Apr 29, 2025 at 12:56 PM Hongtao Liu <crazy...@gmail.com> > > wrote: > > > > > > > > On Sun, Apr 27, 2025 at 10:58 AM H.J. Lu <hjl.to...@gmail.com> wrote: > > > > > > > > > > When passing 0xff as an unsigned char function argument with the C > > > > > frontend promotion, expand_normal used to get > > > > > > > > > > <integer_cst 0x7fffe6aa23a8 type <integer_type 0x7fffe98225e8 int> > > > > > constant 255> > > > > > > > > > > and returned the rtx value using the sign-extended representation: > > > > > > > > > > (const_int 255 [0xff]) > > > > > > > > > > But after > > > > > > > > > > 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 > > > > > > > > > > expand_normal now gets > > > > > > > > > > <integer_cst 0x7fffe9824018 type <integer_type 0x7fffe9822348 > > > > > unsigned char > co nstant 255> > > > > > > > > > > and returns > > > > > > > > > > (const_int -1 [0xffffffffffffffff]) > > > > It sounds like a general issue which should be fixed in > > > > expand_normal instead of fixing it in the backend? > > > > > > It is related to trunc_int_for_mode. I think this is a backend issue. > I see, I guess trunc_int_for_mode itself should be ok since middle end will > add extra sign_extend/zero_extend when it needs to be used in another mode. > But trunc_int_for_mode + intrinsic immediate check caused the problem. > > I can't think of a better solution, so LGTM.
I am checking it in. Thanks. > > > > Please discuss the issue at > > > > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117547 > > > > > > > > > > > > which doesn't work with the predicates nor the instruction > > > > > templates which expect the unsigned expanded value. Extract the > > > > > unsigned char and short integer constants to return > > > > > > > > > > (const_int 255 [0xff]) > > > > > > > > > > so that the expanded value is always unsigned, without the C > > > > > frontend promotion. > > > > > > > > > > PR target/117547 > > > > > * config/i386/i386-expand.cc > > > > > (ix86_expand_unsigned_small_int_cst_argumen > > > > > t): > > > > > New function. > > > > > (ix86_expand_args_builtin): Call > > > > > ix86_expand_unsigned_small_int_cst_argument to expand the argument > > > > > before calling fixup_modeless_constant. > > > > > (ix86_expand_round_builtin): Likewise. > > > > > (ix86_expand_special_args_builtin): Likewise. > > > > > (ix86_expand_builtin): Likewise. > > > > > > > > > > -- > > > > > H.J. > > > > > > > > > > > > > > > > -- > > > > BR, > > > > Hongtao > > > > > > > > > > > > -- > > > H.J. > > > > > > > > -- > > H.J. -- H.J.
