[Bug rtl-optimization/102115] New: symbol address eliminated by the xtensa size optimization

[Bug rtl-optimization/102115] New: symbol address eliminated by the xtensa size optimization

[me at jhdtl dot ru]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102115

            Bug ID: 102115
           Summary: symbol address eliminated by the xtensa size
                    optimization
           Product: gcc
           Version: 12.0
               URL: https://github.com/earlephilhower/newlib-xtensa/issues
                    /19#issuecomment-903203750
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: rtl-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: me at jhdtl dot ru
  Target Milestone: ---
              Host: x86_64-w64-mingw32
            Target: xtensa-lx106-elf
             Build: x86_64-linux-gnu

Created attachment 51370
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=51370&action=edit
Missing symbol example

.\x86_64-w64-mingw32.xtensa-lx106-elf-1757bed.210826\xtensa-lx106-elf\bin\xtensa-lx106-elf-gcc.exe
-v
Using built-in specs.
COLLECT_GCC=C:\Users\maxim\Documents\gist\a433474aa40ab0f6433f9240455fd624\x86_64-w64-mingw32.xtensa-lx106-elf-1757bed.210826\xtensa-lx106-elf\bin\xtensa-lx106-elf-gcc.exe
COLLECT_LTO_WRAPPER=c:/users/maxim/documents/gist/a433474aa40ab0f6433f9240455fd624/x86_64-w64-mingw32.xtensa-lx106-elf-1757bed.210826/xtensa-lx106-elf/bin/../libexec/gcc/xtensa-lx106-elf/12.0.0/lto-wrapper.exe
Target: xtensa-lx106-elf
Configured with: /home/jhdtl/dev/esp-quick-toolchain/repo/gcc-gnu/configure
--prefix=/home/jhdtl/dev/esp-quick-toolchain/xtensa-lx106-elf.win64
--build=x86_64-linux-gnu --host=x86_64-w64-mingw32 --target=xtensa-lx106-elf
--disable-shared --with-newlib --enable-threads=no --disable-__cxa_atexit
--disable-libgomp --disable-libmudflap --disable-nls --disable-multilib
--disable-bootstrap --enable-languages=c,c++ --enable-lto --enable-static=yes
--disable-libstdcxx-verbose
Thread model: single
Supported LTO compression algorithms: zlib
gcc version 12.0.0 20210825 (experimental) (GCC)


After the 64a54505ec8249178b9767d1420354f8eb55de50, using -Os on
x86_64-w64-mingw32 *may* result in missing function symbol in the example
test.ii attached if the symbol's address can be compressed into small number
accepted by the movi + slli.

>From the URL, adding the suggested fprintf to the 'xtensa_emit_move_sequence'
and running with the following command:
$ xtensa-lx106-elf-g++.exe -Os -save-temps -mlongcalls -mtext-section-literals
-falign-functions=4 -ffunction-sections -fdata-sections -Wall
-Werror=return-type -free -fipa-pta -fno-rtti -std=gnu++17 -S -o test.S
test.cpp

Prints when the optimization happens:
[xtensa_emit_move_sequence @ function()] '513540096[0x1e9c0000]' =>
'1959[0x7a7] << 18'
[xtensa_emit_move_sequence @ function()] '513540096[0x1e9c0000]' =>
'1959[0x7a7] << 18'
[xtensa_emit_move_sequence @ function()] '513540096[0x1e9c0000]' =>
'1959[0x7a7] << 18'

Which will not be the expected function address at runtime, and will also
remove the symbol from the resulting object:
test.S:_Z8functionv:                                                           
                                                                               
                           movi    a5, 0x7a7                                   
                                                                               
                                       slli    a5, a5, 18                      
                                                                               
                                                   l32r    a4, .LC209          
                                                                               
                                                               l32r    a2,
.LC426                                                                         
                                                                               
mov.n   a3, a5                                                                 
                                                                               
            s32i.n  a5, sp, 20                                                 
                                                                               
                        call0   _Z8three132PFvPFvPFvvEES0_ES2_S0_

[Bug target/102115] symbol address eliminated by the xtensa size optimization

[jcmvbkbc at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102115

jcmvbkbc at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jcmvbkbc at gcc dot gnu.org
   Last reconfirmed|                            |2021-09-07
           Assignee|unassigned at gcc dot gnu.org      |jcmvbkbc at gcc dot gnu.org
             Status|UNCONFIRMED                 |ASSIGNED
     Ever confirmed|0                           |1

--- Comment #1 from jcmvbkbc at gcc dot gnu.org ---
Thanks for the report and analysis. The following part needs a bit of
explanation:

After the 64a54505ec8249178b9767d1420354f8eb55de50, using -Os on
x86_64-w64-mingw32 *may* result in missing function symbol in the example
test.ii attached if the symbol's address can be compressed into small number
accepted by the movi + slli.

It's not about the address that corresponds to the symbol in the target code
(e.g. in the attached example the target addresses are all unknown), but about
the RTX node address that describes the symbol inside the compiler. That makes
this bug hard to reproduce.

[Bug target/102115] symbol address eliminated by the xtensa size optimization

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102115

--- Comment #2 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Max Filippov <jcmvbkbc@gcc.gnu.org>:

https://gcc.gnu.org/g:b552c4e601c7fdc4d341e29cc1ed6081d42b00d0

commit r12-3402-gb552c4e601c7fdc4d341e29cc1ed6081d42b00d0
Author: Max Filippov <jcmvbkbc@gmail.com>
Date:   Tue Sep 7 15:40:00 2021 -0700

    gcc: xtensa: fix PR target/102115

    2021-09-07  Takayuki 'January June' Suwa  <jjsuwa_sys3175@yahoo.co.jp>
    gcc/
            PR target/102115
            * config/xtensa/xtensa.c (xtensa_emit_move_sequence): Add
            'CONST_INT_P (src)' to the condition of the block that tries to
            eliminate literal when loading integer contant.

[Bug target/102115] symbol address eliminated by the xtensa size optimization

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102115

--- Comment #3 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-11 branch has been updated by Max Filippov
<jcmvbkbc@gcc.gnu.org>:

https://gcc.gnu.org/g:dcb2873cd32b263643bfd9d1298b35d6cd028f0a

commit r11-8969-gdcb2873cd32b263643bfd9d1298b35d6cd028f0a
Author: Max Filippov <jcmvbkbc@gmail.com>
Date:   Tue Sep 7 15:40:00 2021 -0700

    gcc: xtensa: fix PR target/102115

    2021-09-07  Takayuki 'January June' Suwa  <jjsuwa_sys3175@yahoo.co.jp>
    gcc/
            PR target/102115
            * config/xtensa/xtensa.c (xtensa_emit_move_sequence): Add
            'CONST_INT_P (src)' to the condition of the block that tries to
            eliminate literal when loading integer contant.

    (cherry picked from commit b552c4e601c7fdc4d341e29cc1ed6081d42b00d0)

[Bug target/102115] symbol address eliminated by the xtensa size optimization

[jcmvbkbc at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102115

jcmvbkbc at gcc dot gnu.org changed:

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

--- Comment #4 from jcmvbkbc at gcc dot gnu.org ---
The fix is committed to master and releases/gcc-11 branch.