[Bug c/112707] New: gcc 14 outputs invalid assembly on ppc: Error: unrecognized opcode: `fctid'

[Bug c/112707] New: gcc 14 outputs invalid assembly on ppc: Error: unrecognized opcode: `fctid'

[csfore at posteo dot net]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112707

            Bug ID: 112707
           Summary: gcc 14 outputs invalid assembly on ppc: Error:
                    unrecognized opcode: `fctid'
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: csfore at posteo dot net
  Target Milestone: ---

Created attachment 56682
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=56682&action=edit
original preprocessed file

Error is first hit when building libvorbis-1.3.7-r1. Needs `gcc -O3 -ffast-math
foo.i to reproduce`. It is successful on GCC 13

`
/tmp/ccv3vNGH.s: Assembler messages:
/tmp/ccv3vNGH.s:34: Error: unrecognized opcode: `fctid'
`

I believe this is a GCC bug given that Apple release notes[0] specifically
state this instruction is 64-bit only (it's a bit down, but a search for the
instruction should find it)


[0]:
https://opensource.apple.com/source/cctools/cctools-446.1/as/notes.auto.html

gcc -v:
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/libexec/gcc/powerpc-unknown-linux-gnu/14/lto-wrapper
Target: powerpc-unknown-linux-gnu
Configured with:
/var/tmp/portage/sys-devel/gcc-14.0.0_pre20231119/work/gcc-14-20231119/configure
--host=powerpc-unknown-linux-gnu --build=powerpc-unknown-linux-gnu
--prefix=/usr --bindir=/usr/powerpc-unknown-linux-gnu/gcc-bin/14
--includedir=/usr/lib/gcc/powerpc-unknown-linux-gnu/14/include
--datadir=/usr/share/gcc-data/powerpc-unknown-linux-gnu/14
--mandir=/usr/share/gcc-data/powerpc-unknown-linux-gnu/14/man
--infodir=/usr/share/gcc-data/powerpc-unknown-linux-gnu/14/info
--with-gxx-include-dir=/usr/lib/gcc/powerpc-unknown-linux-gnu/14/include/g++-v14
--disable-silent-rules --disable-dependency-tracking
--with-python-dir=/share/gcc-data/powerpc-unknown-linux-gnu/14/python
--enable-languages=c,c++,fortran --enable-obsolete --enable-secureplt
--disable-werror --with-system-zlib --enable-nls --without-included-gettext
--disable-libunwind-exceptions --enable-checking=yes,extra
--with-bugurl=https://bugs.gentoo.org/ --with-pkgversion='Gentoo
14.0.0_pre20231119 p9' --with-gcc-major-version-only --enable-libstdcxx-time
--enable-lto --disable-libstdcxx-pch --enable-shared --enable-threads=posix
--enable-__cxa_atexit --enable-clocale=gnu --disable-multilib
--disable-fixed-point --enable-targets=all --enable-libgomp --disable-libssp
--disable-libada --disable-cet --disable-systemtap
--disable-valgrind-annotations --disable-vtable-verify --disable-libvtv
--without-zstd --without-isl --enable-default-pie --enable-host-pie
--disable-host-bind-now --enable-default-ssp
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 14.0.0 20231119 (experimental) (Gentoo 14.0.0_pre20231119 p9)

[Bug target/112707] [14 regression] gcc 14 outputs invalid assembly on ppc: Error: unrecognized opcode: `fctid'

[csfore at posteo dot net]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112707

--- Comment #1 from Christopher Fore <csfore at posteo dot net> ---
Created attachment 56683
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=56683&action=edit
trimmed file with cvise

[Bug target/112707] [14 regression] gcc 14 outputs invalid assembly on ppc: Error: unrecognized opcode: `fctid'

[csfore at posteo dot net]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112707

--- Comment #2 from Christopher Fore <csfore at posteo dot net> ---
Created attachment 56684
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=56684&action=edit
assembly output of sharedbook.i

[Bug target/112707] [14 regression] gcc 14 outputs invalid assembly on ppc: Error: unrecognized opcode: `fctid'

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112707

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |14.0

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
I am 99% sure it was caused by
r14-4485-gc1e474785859c9630fcae19c8d2d606f5642c636 .

I suspect the check on lrint<mode>di2 should have been changed to
`TARGET_HARD_FLOAT && TARGET_POWERPC64` instead of just `TARGET_HARD_FLOAT`.

[Bug target/112707] [14 regression] gcc 14 outputs invalid assembly on ppc: Error: unrecognized opcode: `fctid'

[guihaoc at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112707

HaoChen Gui <guihaoc at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |linkw at gcc dot gnu.org

--- Comment #4 from HaoChen Gui <guihaoc at gcc dot gnu.org> ---
I can't reproduce it on my env. Could you inform me the assembler version and
CPU type you used or the default CPU type. Thanks.

[Bug target/112707] [14 regression] gcc 14 outputs invalid assembly on ppc: Error: unrecognized opcode: `fctid'

[csfore at posteo dot net]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112707

--- Comment #5 from Christopher Fore <csfore at posteo dot net> ---
It's a PowerPC 7447A and the assembler version is:

GNU assembler version 2.40.0 (powerpc-unknown-linux-gnu) using BFD version
(Gentoo 2.40 p5) 2.40.0

[Bug target/112707] [14 regression] gcc 14 outputs invalid assembly on ppc: Error: unrecognized opcode: `fctid'

[csfore at posteo dot net]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112707

--- Comment #6 from Christopher Fore <csfore at posteo dot net> ---
The original example in the wild was with -mcpu=7450 -O2 -maltivec
-mabi=altivec -pipe, plus the flags the build system added, then I minimised it
to the attachment above, where I only needed: -O3 -ffast-math.

[Bug target/112707] [14 regression] gcc 14 outputs invalid assembly on ppc: Error: unrecognized opcode: `fctid'

[csfore at posteo dot net]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112707

--- Comment #7 from Christopher Fore <csfore at posteo dot net> ---
Created attachment 56691
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=56691&action=edit
build log of the original compile

[Bug target/112707] [14 regression] gcc 14 outputs invalid assembly on ppc: Error: unrecognized opcode: `fctid'

[segher at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112707

Segher Boessenkool <segher at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |segher at gcc dot gnu.org

--- Comment #8 from Segher Boessenkool <segher at gcc dot gnu.org> ---
Yeah, it tested for ISA 2.04 before.  That was an attempt at including 476
probably?

We really should have a TARGET_FCTID, on for TARGET_POWERPC64 or for cpu 476
(so
NOT user-selectable separately, of course!); not try to use pre-existing flags
for this, which might work but will forever stay confusing.

So either a separate OPTION_FCTID for in rs6000-cpus.def, or TARGET_FCTID. 
Either
works for me.

(Background: in ISA 1.xx it was for 64-bit implementations only.  But it does
not
need 64-bit registers or a 64-bit integer pipeline at all, it is an FP
instruction
that works on FP registers, which always are 64-bit.  The instruction was
implemented
on the 476).

[Bug target/112707] [14 regression] gcc 14 outputs invalid assembly on ppc: Error: unrecognized opcode: `fctid'

[guihaoc at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112707

--- Comment #9 from HaoChen Gui <guihaoc at gcc dot gnu.org> ---
(In reply to Segher Boessenkool from comment #8)
> Yeah, it tested for ISA 2.04 before.  That was an attempt at including 476
> probably?
> 
> We really should have a TARGET_FCTID, on for TARGET_POWERPC64 or for cpu 476
> (so
> NOT user-selectable separately, of course!); not try to use pre-existing
> flags for this, which might work but will forever stay confusing.
> 
> So either a separate OPTION_FCTID for in rs6000-cpus.def, or TARGET_FCTID. 
> Either
> works for me.
> 
> (Background: in ISA 1.xx it was for 64-bit implementations only.  But it
> does not
> need 64-bit registers or a 64-bit integer pipeline at all, it is an FP
> instruction
> that works on FP registers, which always are 64-bit.  The instruction was
> implemented
> on the 476).

Thanks for your explanation.

I found "fctid" is supported on PPC64 and PPC476 from assembler source code.
{“fctid”,       XRC(63,814,0),  XRA_MASK,    PPC64,     PPCVLE,         {FRT,
FRB}},
{“fctid”,       XRC(63,814,0),  XRA_MASK,    PPC476,    PPCVLE,         {FRT,
FRB}},

But powerpc7450 only enables PPC. That's why assembler complains.
  { "7450",    PPC_OPCODE_PPC | PPC_OPCODE_7450 | PPC_OPCODE_ALTIVEC, 0 },

My question is: can "fctid" be executed on powerpc7450 such a 32bit processor?
If it's supported, should the assembler be changed also (replace the PPC64 with
PPC for fctid)?

[Bug target/112707] [14 regression] gcc 14 outputs invalid assembly on ppc: Error: unrecognized opcode: `fctid'

[linkw at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112707

--- Comment #10 from Kewen Lin <linkw at gcc dot gnu.org> ---
(In reply to HaoChen Gui from comment #9)
> (In reply to Segher Boessenkool from comment #8)
> > Yeah, it tested for ISA 2.04 before.  That was an attempt at including 476
> > probably?
> > 
> > We really should have a TARGET_FCTID, on for TARGET_POWERPC64 or for cpu 476
> > (so
> > NOT user-selectable separately, of course!); not try to use pre-existing
> > flags for this, which might work but will forever stay confusing.
> > 
> > So either a separate OPTION_FCTID for in rs6000-cpus.def, or TARGET_FCTID. 
> > Either
> > works for me.
> > 
> > (Background: in ISA 1.xx it was for 64-bit implementations only.  But it
> > does not
> > need 64-bit registers or a 64-bit integer pipeline at all, it is an FP
> > instruction
> > that works on FP registers, which always are 64-bit.  The instruction was
> > implemented
> > on the 476).
> 
> Thanks for your explanation.
> 
> I found "fctid" is supported on PPC64 and PPC476 from assembler source code.
> {“fctid”,       XRC(63,814,0),  XRA_MASK,    PPC64,     PPCVLE,        
> {FRT, FRB}},
> {“fctid”,       XRC(63,814,0),  XRA_MASK,    PPC476,    PPCVLE,        
> {FRT, FRB}},
> 
> But powerpc7450 only enables PPC. That's why assembler complains.
>   { "7450",    PPC_OPCODE_PPC | PPC_OPCODE_7450 | PPC_OPCODE_ALTIVEC, 0 },
> 
> My question is: can "fctid" be executed on powerpc7450 such a 32bit
> processor? If it's supported, should the assembler be changed also (replace
> the PPC64 with PPC for fctid)?

Good question, I think it's no, the assembler implementation looks to match the
documentation, as I can't find insn fctid in powerpc7450 doc:
https://www.nxp.com.cn/docs/en/reference-manual/MPC7450UM.pdf

[Bug target/112707] [14 regression] gcc 14 outputs invalid assembly on ppc: Error: unrecognized opcode: `fctid'

[bergner at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112707

--- Comment #11 from Peter Bergner <bergner at gcc dot gnu.org> ---
(In reply to Kewen Lin from comment #10)
> (In reply to HaoChen Gui from comment #9)
>
>> My question is: can "fctid" be executed on powerpc7450 such a 32bit
>> processor? If it's supported, should the assembler be changed also (replace
>> the PPC64 with PPC for fctid)?
> 
> Good question, I think it's no, the assembler implementation looks to match
> the documentation, as I can't find insn fctid in powerpc7450 doc:
> https://www.nxp.com.cn/docs/en/reference-manual/MPC7450UM.pdf

I believe the only 32-bit cpu that supports fctid is the 476 which has
explicitly enabled it here.

[Bug target/112707] [14 regression] gcc 14 outputs invalid assembly on ppc: Error: unrecognized opcode: `fctid'

[bergner at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112707

Peter Bergner <bergner at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2023-12-05

--- Comment #12 from Peter Bergner <bergner at gcc dot gnu.org> ---
Confirmed.

A simpler test case with minimal rtl insns.  I'll note that you don't always
get an assembler error, since gcc still passes -many to the assembler for non
--enable-checking gcc builds, which causes it to accept the fctid insn.

extern double rint (double);
void
foo (long long *dst, double a)
{
  *dst = rint (a);
}

[Bug target/112707] [14 regression] gcc 14 outputs invalid assembly on ppc: Error: unrecognized opcode: `fctid'

[segher at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112707

--- Comment #13 from Segher Boessenkool <segher at gcc dot gnu.org> ---
(In reply to Peter Bergner from comment #12)
> I'll note that you don't always
> get an assembler error, since gcc still passes -many to the assembler for
> non --enable-checking gcc builds, which causes it to accept the fctid insn.

Hrm.  Was that an oversight?  Should we always do that now?  Can you prepare a
patch (and test on some common configs) please?

[Bug target/112707] [14 regression] gcc 14 outputs invalid assembly on ppc: Error: unrecognized opcode: `fctid'

[bergner at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112707

--- Comment #14 from Peter Bergner <bergner at gcc dot gnu.org> ---
(In reply to Segher Boessenkool from comment #13)
> (In reply to Peter Bergner from comment #12)
> > I'll note that you don't always
> > get an assembler error, since gcc still passes -many to the assembler for
> > non --enable-checking gcc builds, which causes it to accept the fctid insn.
> 
> Hrm.  Was that an oversight?  Should we always do that now?  Can you prepare
> a patch (and test on some common configs) please?

I was surprised as you that we were still passing -many to the assembler under
some circumstances.  That said, removing all -many usage is orthogonal to this
bug.  I'll open another bug where we can discuss what to do wrt that.

[Bug target/112707] [14 regression] gcc 14 outputs invalid assembly on ppc: Error: unrecognized opcode: `fctid'

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112707

--- Comment #15 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by HaoChen Gui <guihaoc@gcc.gnu.org>:

https://gcc.gnu.org/g:46e342b985e6b4058db73875103cced2666e84e2

commit r14-6391-g46e342b985e6b4058db73875103cced2666e84e2
Author: Haochen Gui <guihaoc@gcc.gnu.org>
Date:   Mon Dec 11 08:40:34 2023 +0800

    rs6000: Enable lrint<mode>si2 on old archs with stfiwx enabled

    The powerpc 32-bit processors (e.g. 5470) supports "fctiw" instruction,
    but the instruction can't be generated on such platforms as the insn is
    guard by TARGET_POPCNTD.  The root cause is SImode in float register is
    supported from Power7.  Actually implementation of "fctiw" only needs
    stfiwx which is supported by the old 32-bit processors.  This patch
    enables "fctiw" expand for these processors.

    gcc/
            PR target/112707
            * config/rs6000/rs6000.md (expand lrint<mode>si2): New.
            (insn lrint<mode>si2): Rename to...
            (*lrint<mode>si): ...this.
            (lrint<mode>si_di): New.

    gcc/testsuite/
            PR target/112707
            * gcc.target/powerpc/pr112707-1.c: New.

[Bug target/112707] [14 regression] gcc 14 outputs invalid assembly on ppc: Error: unrecognized opcode: `fctid'

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112707

--- Comment #16 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by HaoChen Gui <guihaoc@gcc.gnu.org>:

https://gcc.gnu.org/g:ae226cb1ee17d61c416c9d4d8c5a142788b8afff

commit r14-6392-gae226cb1ee17d61c416c9d4d8c5a142788b8afff
Author: Haochen Gui <guihaoc@gcc.gnu.org>
Date:   Mon Dec 11 08:41:55 2023 +0800

    rs6000: Guard fctid on PowerPC64 and PowerPC476

    fctid is only supported on 64-bit Power processors and powerpc 476. It
    should be guarded by this condition. The patch fixes the issue.

    gcc/
            PR target/112707
            * config/rs6000/rs6000.h (TARGET_FCTID): Define.
            * config/rs6000/rs6000.md (lrint<mode>di2): Add guard TARGET_FCTID.
            * (lround<mode>di2): Replace TARGET_FPRND with TARGET_FCTID.

    gcc/testsuite/
            PR target/112707
            * gcc.target/powerpc/pr112707.h: New.
            * gcc.target/powerpc/pr112707-2.c: New.
            * gcc.target/powerpc/pr112707-3.c: New.
            * gcc.target/powerpc/pr88558-p7.c: Check fctid on ilp32 and
            has_arch_ppc64 as it's now guarded by powerpc64.
            * gcc.target/powerpc/pr88558-p8.c: Likewise.
            * gfortran.dg/nint_p7.f90: Add powerpc64 target requirement as
            lround<mode>di2 is now guarded by powerpc64.

[Bug target/112707] [14 regression] gcc 14 outputs invalid assembly on ppc: Error: unrecognized opcode: `fctid'

[guihaoc at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112707

HaoChen Gui <guihaoc at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |FIXED
             Status|NEW                         |RESOLVED

--- Comment #17 from HaoChen Gui <guihaoc at gcc dot gnu.org> ---
fixed