[Bug target/116195] New: arm: ICE building pr111150.C

[Bug target/116195] New: arm: ICE building pr111150.C

[adhemerval.zanella at linaro dot org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116195

            Bug ID: 116195
           Summary: arm: ICE building pr111150.C
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: adhemerval.zanella at linaro dot org
  Target Milestone: ---

It seems that this change triggered with Linaro CI on arm 32 bit [1]:

--
Executing on host:
/home/tcwg-buildslave/workspace/tcwg_gnu_1/abe/builds/destdir/x86_64-pc-linux-gnu/bin/arm-eabi-g++
 
/home/tcwg-buildslave/workspace/tcwg_gnu_1/abe/snapshots/gcc.git~master/gcc/testsuite/g++.dg/tree-ssa/pr111150.C
 -mthumb -march=armv8.1-m.main+mve.fp+fp.dp -mtune=cortex-m55 -mfloat-abi=hard
-mfpu=auto   -fdiagnostics-plain-output  -nostdinc++
-I/home/tcwg-buildslave/workspace/tcwg_gnu_1/abe/builds/x86_64-pc-linux-gnu/arm-eabi/gcc-gcc.git~master-stage2/arm-eabi/libstdc++-v3/include/arm-eabi
-I/home/tcwg-buildslave/workspace/tcwg_gnu_1/abe/builds/x86_64-pc-linux-gnu/arm-eabi/gcc-gcc.git~master-stage2/arm-eabi/libstdc++-v3/include
-I/home/tcwg-buildslave/workspace/tcwg_gnu_1/abe/snapshots/gcc.git~master/libstdc++-v3/libsupc++
-I/home/tcwg-buildslave/workspace/tcwg_gnu_1/abe/snapshots/gcc.git~master/libstdc++-v3/include/backward
-I/home/tcwg-buildslave/workspace/tcwg_gnu_1/abe/snapshots/gcc.git~master/libstdc++-v3/testsuite/util
-fmessage-length=0  -std=gnu++98 -O1 -fdump-tree-forwprop1 -Wno-psabi  -S  -o
pr111150.s    (timeout = 600)
spawn -ignore SIGHUP
/home/tcwg-buildslave/workspace/tcwg_gnu_1/abe/builds/destdir/x86_64-pc-linux-gnu/bin/arm-eabi-g++
/home/tcwg-buildslave/workspace/tcwg_gnu_1/abe/snapshots/gcc.git~master/gcc/testsuite/g++.dg/tree-ssa/pr111150.C
-mthumb -march=armv8.1-m.main+mve.fp+fp.dp -mtune=cortex-m55 -mfloat-abi=hard
-mfpu=auto -fdiagnostics-plain-output -nostdinc++
-I/home/tcwg-buildslave/workspace/tcwg_gnu_1/abe/builds/x86_64-pc-linux-gnu/arm-eabi/gcc-gcc.git~master-stage2/arm-eabi/libstdc++-v3/include/arm-eabi
-I/home/tcwg-buildslave/workspace/tcwg_gnu_1/abe/builds/x86_64-pc-linux-gnu/arm-eabi/gcc-gcc.git~master-stage2/arm-eabi/libstdc++-v3/include
-I/home/tcwg-buildslave/workspace/tcwg_gnu_1/abe/snapshots/gcc.git~master/libstdc++-v3/libsupc++
-I/home/tcwg-buildslave/workspace/tcwg_gnu_1/abe/snapshots/gcc.git~master/libstdc++-v3/include/backward
-I/home/tcwg-buildslave/workspace/tcwg_gnu_1/abe/snapshots/gcc.git~master/libstdc++-v3/testsuite/util
-fmessage-length=0 -std=gnu++98 -O1 -fdump-tree-forwprop1 -Wno-psabi -S -o
pr111150.s
/home/tcwg-buildslave/workspace/tcwg_gnu_1/abe/snapshots/gcc.git~master/gcc/testsuite/g++.dg/tree-ssa/pr111150.C:
In function 'v4si f1_(v4si, v4si, v4si, v4si, v4si, v4si)':
/home/tcwg-buildslave/workspace/tcwg_gnu_1/abe/snapshots/gcc.git~master/gcc/testsuite/g++.dg/tree-ssa/pr111150.C:13:1:
error: unrecognizable insn:
(insn 22 21 26 2 (set (reg:V4SI 120 [ <retval> ])
        (unspec:V4SI [
                (reg:V4SI 136)
                (reg:V4SI 137)
                (subreg:V4BI (reg:HI 135) 0)
            ] VPSELQ_S))
"/home/tcwg-buildslave/workspace/tcwg_gnu_1/abe/snapshots/gcc.git~master/gcc/testsuite/g++.dg/tree-ssa/pr111150.C":12:17
-1
     (nil))
during RTL pass: vregs
/home/tcwg-buildslave/workspace/tcwg_gnu_1/abe/snapshots/gcc.git~master/gcc/testsuite/g++.dg/tree-ssa/pr111150.C:13:1:
internal compiler error: in extract_insn, at recog.cc:2848
0x21fd635 internal_error(char const*, ...)
        ../../../../../../gcc/gcc/diagnostic-global-context.cc:491
0x9a0958 fancy_abort(char const*, int, char const*)
        ../../../../../../gcc/gcc/diagnostic.cc:1725
0x840e4d _fatal_insn(char const*, rtx_def const*, char const*, int, char
const*)
        ../../../../../../gcc/gcc/rtl-error.cc:108
0x840e6f _fatal_insn_not_found(rtx_def const*, char const*, int, char const*)
        ../../../../../../gcc/gcc/rtl-error.cc:116
0x83f76b extract_insn(rtx_insn*)
        ../../../../../../gcc/gcc/recog.cc:2848
0xf1a805 instantiate_virtual_regs_in_insn
        ../../../../../../gcc/gcc/function.cc:1612
0xf1a805 instantiate_virtual_regs
        ../../../../../../gcc/gcc/function.cc:1995
0xf1a805 execute
        ../../../../../../gcc/gcc/function.cc:2042
--

Accordingly to Andrew Piski, this is backend bug that was exposed by the patch.

`vcond_mask_<mode><MVE_vpred>` for operand[3] uses s_register_operand which
allows subreg but then it creates a VPSELQ_S unspec which uses
vpr_register_operand as the operand which does not allow subreg and
does not forces into a register.


[1]
https://ci.linaro.org/job/tcwg_gnu_embed_check_gcc--master-thumb_m55_hard_eabi-build/517/artifact/artifacts/00-sumfiles/

[Bug target/116195] [MVE] arm: ICE building pr111150.C

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116195

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|arm: ICE building           |[MVE] arm: ICE building
                   |pr111150.C                  |pr111150.C
     Ever confirmed|0                           |1
           Keywords|                            |ice-on-valid-code
             Target|                            |arm-eabi
             Status|UNCONFIRMED                 |NEW
            Version|14.0                        |15.0
   Last reconfirmed|                            |2024-08-02

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Note using -fno-tree-ter also works around the backend issue because we don't
end up with a subreg with that.