[Bug c/106972] New: internal compiler error: in extract_insn, at recog.c:2770 on ARMeb when building gcc itself

[Bug c/106972] New: internal compiler error: in extract_insn, at recog.c:2770 on ARMeb when building gcc itself

[thomas.petazzoni@free-electrons.com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106972

            Bug ID: 106972
           Summary: internal compiler error: in extract_insn, at
                    recog.c:2770 on ARMeb when building gcc itself
           Product: gcc
           Version: 11.3.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: thomas.petazzoni@free-electrons.com
  Target Milestone: ---

When building gcc 11.3.0 for armeb, with the following configure command line:


(cd
/home/thomas/autobuild/instance-1/output-1/build/host-gcc-initial-11.3.0/build
&& rm -rf config.cache;
PATH="/home/thomas/autobuild/instance-1/output-1/host/bin:/home/thomas/autobuild/instance-1/output-1/host/sbin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/snap/bin"
PKG_CONFIG="/home/thomas/autobuild/instance-1/output-1/host/bin/pkg-config"
PKG_CONFIG_SYSROOT_DIR="/" PKG_CONFIG_ALLOW_SYSTEM_CFLAGS=1
PKG_CONFIG_ALLOW_SYSTEM_LIBS=1
PKG_CONFIG_LIBDIR="/home/thomas/autobuild/instance-1/output-1/host/lib/pkgconfig:/home/thomas/autobuild/instance-1/output-1/host/share/pkgconfig"
AR="/usr/bin/ar" AS="/usr/bin/as" LD="/usr/bin/ld" NM="/usr/bin/nm"
CC="/usr/bin/gcc" GCC="/usr/bin/gcc" CXX="/usr/bin/g++" CPP="/usr/bin/cpp"
OBJCOPY="/usr/bin/objcopy" RANLIB="/usr/bin/ranlib"
CPPFLAGS="-I/home/thomas/autobuild/instance-1/output-1/host/include"
CFLAGS="-O2 -I/home/thomas/autobuild/instance-1/output-1/host/include"
CXXFLAGS="-O2 -I/home/thomas/autobuild/instance-1/output-1/host/include"
LDFLAGS="-L/home/thomas/autobuild/instance-1/output-1/host/lib
-Wl,-rpath,/home/thomas/autobuild/instance-1/output-1/host/lib"
INTLTOOL_PERL=/usr/bin/perl CFLAGS="-O2
-I/home/thomas/autobuild/instance-1/output-1/host/include"
LDFLAGS="-L/home/thomas/autobuild/instance-1/output-1/host/lib
-Wl,-rpath,/home/thomas/autobuild/instance-1/output-1/host/lib"
MAKEINFO=missing CFLAGS_FOR_TARGET="-D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE
-D_FILE_OFFSET_BITS=64  -Os -g0 -D_FORTIFY_SOURCE=1"
CXXFLAGS_FOR_TARGET="-D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE
-D_FILE_OFFSET_BITS=64  -Os -g0 -D_FORTIFY_SOURCE=1" AR_FOR_TARGET=gcc-ar
NM_FOR_TARGET=gcc-nm RANLIB_FOR_TARGET=gcc-ranlib CONFIG_SITE=/dev/null
./configure --prefix="/home/thomas/autobuild/instance-1/output-1/host"
--sysconfdir="/home/thomas/autobuild/instance-1/output-1/host/etc"
--localstatedir="/home/thomas/autobuild/instance-1/output-1/host/var"
--enable-shared --disable-static --disable-gtk-doc --disable-gtk-doc-html
--disable-doc --disable-docs --disable-documentation --disable-debug
--with-xmlto=no --with-fop=no --disable-nls --disable-dependency-tracking 
--target=armeb-buildroot-linux-gnueabi
--with-sysroot=/home/thomas/autobuild/instance-1/output-1/host/armeb-buildroot-linux-gnueabi/sysroot
--enable-__cxa_atexit --with-gnu-ld --disable-libssp --disable-multilib
--disable-decimal-float --enable-plugins --enable-lto
--with-gmp=/home/thomas/autobuild/instance-1/output-1/host
--with-mpc=/home/thomas/autobuild/instance-1/output-1/host
--with-mpfr=/home/thomas/autobuild/instance-1/output-1/host
--with-pkgversion="Buildroot 2022.08-rc1-468-g0f42b81532"
--with-bugurl="http://bugs.buildroot.net/" --without-zstd --disable-libquadmath
--disable-libquadmath-support --enable-tls --enable-threads --without-isl
--without-cloog --with-float=soft --with-abi="aapcs-linux" --with-cpu=iwmmxt
--with-float=soft --with-mode=arm --enable-languages=c --disable-shared
--without-headers --disable-threads --with-newlib --disable-largefile  )

The build fails with:

../../../libgcc/config/arm/unwind-arm.c:467:1: error: unrecognizable insn:
  467 | }
      | ^
(insn 2 4 3 2 (set (reg/v/f:SI 118 [ p ])
        (reg:SI 0 r0 [ p ])) "../../../libgcc/config/arm/unwind-arm.c":456:1 -1
     (nil))
during RTL pass: vregs
../../../libgcc/config/arm/unwind-arm.c:467:1: internal compiler error: in
extract_insn, at recog.c:2770

(The same error happens in several place)

Full build log at
http://autobuild.buildroot.net/results/8e4c4512902c34d8ec0c6f8dfff92b7a198e4b4a/build-end.log

There are a number of similar reports, but they don't seem to apply:
- https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99724 is already fixed in gcc
11.3.0
- https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102222 is S390 specific

[Bug target/106972] internal compiler error: in extract_insn, at recog.c:2770 on ARMeb when building gcc itself

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106972

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           See Also|                            |https://gcc.gnu.org/bugzill
                   |                            |a/show_bug.cgi?id=106279

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
iwmmxt support is definitely bitrotten and most likely should be removed from
GCC.

[Bug target/106972] internal compiler error: in extract_insn, at recog.c:2770 on ARMeb when building gcc itself

[thomas.petazzoni@free-electrons.com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106972

--- Comment #2 from Thomas Petazzoni <thomas.petazzoni@free-electrons.com> ---
Thanks for the quick feedback! I am not super familiar with iwmmxt, but as I
understand it is used in Marvell PXA270 and above. While these are fairly old
indeed, their support is still maintained in the upstream Linux kernel, so it
would be odd to no longer have gcc support for them.

[Bug target/106972] internal compiler error: in extract_insn, at recog.c:2770 on ARMeb when building gcc itself

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106972

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Thomas Petazzoni from comment #2)
> Thanks for the quick feedback! I am not super familiar with iwmmxt, but as I
> understand it is used in Marvell PXA270 and above. While these are fairly
> old indeed, their support is still maintained in the upstream Linux kernel,
> so it would be odd to no longer have gcc support for them.

Marvell does not provide any support for them in the last 4 years or more. With
my Marvell hat on, it makes sense to remove the GCC support as it definitely
has bitrotten and I have no resources at all to do any upstream fixes for it.

[Bug target/106972] internal compiler error: in extract_insn, at recog.c:2770 on ARMeb when building gcc itself

[rearnsha at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106972

--- Comment #4 from Richard Earnshaw <rearnsha at gcc dot gnu.org> ---
I don't think we're talking about removing support for the CPU, just support
for the iwmmxt extension.  That is, you can still use it as an Arm cpu, but
without the vector engine.

[Bug target/106972] internal compiler error: in extract_insn, at recog.c:2770 on ARMeb when building gcc itself

[thomas.petazzoni@free-electrons.com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106972

--- Comment #5 from Thomas Petazzoni <thomas.petazzoni@free-electrons.com> ---
ACK, but what we're using in this configuration is --with-cpu=iwmmxt. I'm a bit
confused between it being a CPU type, and it being just a vector extension.

[Bug target/106972] internal compiler error: in extract_insn, at recog.c:2770 on ARMeb when building gcc itself

[rearnsha at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106972

--- Comment #6 from Richard Earnshaw <rearnsha at gcc dot gnu.org> ---
Nobody has proposed any patches yet, but I imagine we'd end up treating
-mcpu=iwmmxt[2] in the same way as -mcpu=xscale.  Similarly for
-march=iwmmxt[2].

[Bug target/106972] internal compiler error: in extract_insn, at recog.c:2770 on ARMeb when building gcc itself

[thomas.petazzoni@free-electrons.com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106972

Thomas Petazzoni <thomas.petazzoni@free-electrons.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |WONTFIX

--- Comment #7 from Thomas Petazzoni <thomas.petazzoni@free-electrons.com> ---
Thanks for the feedback. We have disabled support for iwmmxt in Buildroot, so
this issue is no longer a problem for us. I will therefore close, marking as
WONTFIX, as it was indicated that this would not be fixed.