[Bug c++/100279] New: Invalid generated assembly for NTTP lambda with negative double value

[Bug c++/100279] New: Invalid generated assembly for NTTP lambda with negative double value

[bobmiller at nvidia dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100279

            Bug ID: 100279
           Summary: Invalid generated assembly for NTTP lambda with
                    negative double value
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: bobmiller at nvidia dot com
  Target Milestone: ---

Created attachment 50683
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=50683&action=edit
The preprocessed file that triggers the bug

I've stumbled across an obscure behavior that results in incorrect assembly
generation: the same signature is generated twice, which the assembler later
(correctly) rejects. I've tested this on GCC-11 and trunk, on my own machine
and godbolt ( example here: https://godbolt.org/z/6eEnKca9o )

Minimal example: 
----------------------------
template<auto V> struct T {};

template<class F> void E(F &&) {}

template<auto V, decltype(V)...Vs, class F>
void E(F &&f)
{
    f(T<V>{});
    E<Vs...>(f);
}

void foo()
{
    E<-1.0, -2.0>(
    [&]<auto X>(T<X>){});
}

int main(int, char**) {}
--------------------------

Interestingly, this does NOT occur for floats or long doubles: only doubles:
changing the suffixes of -1.0 and -2.0 above to -1.0f and -2.0f (or -1.0L and
-2.0L) results in valid generated code.

------------------
Output from gcc -v:

COLLECT_GCC=g++-11
COLLECT_LTO_WRAPPER=/home/bob/libexec/gcc/x86_64-linux-gnu/12.0.0/lto-wrapper
Target: x86_64-linux-gnu
Configured with: ../gcc/configure -v --build=x86_64-linux-gnu
--host=x86_64-linux-gnu --target=x86_64-linux-gnu --prefix=/home/bob/
--enable-checking=release --enable-languages=c,c++ --disable-multilib
--program-suffix=-11
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 12.0.0 20210426 (experimental) (GCC) 


Command line to trigger bug: g++-11 --std=c++20 bugtest.cpp -o test

Compiler output:
/tmp/ccmrd0Wr.s: Assembler messages:
/tmp/ccmrd0Wr.s:106: Error: symbol
`_ZZ3foovENKUl1TIXT_EEE_clILdffffffff00000000EEEDaS0_' is already defined

[Bug c++/100279] Invalid generated assembly for NTTP lambda with negative double value

[bobmiller at nvidia dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100279

--- Comment #1 from Bob Miller <bobmiller at nvidia dot com> ---
Created attachment 50684
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=50684&action=edit
New preprocessed source for more minimal example. This one leads to an ICE on
godbolt's GCC version.

[Bug c++/100279] Invalid generated assembly for NTTP lambda with negative double value

[bobmiller at nvidia dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100279

--- Comment #2 from Bob Miller <bobmiller at nvidia dot com> ---
In further minifying this example, I've discovered a related ICE. The ICE can
be seen on godbolt here: https://godbolt.org/z/vxzG1zMjo

I've attached a new preprocessed file that triggers the ICE. Code is as
follows:

template<auto V> struct T {};

template<auto X>
void f(T<X>) {}

template<auto V, auto V2>
void E()
{
    f(T<V>{});
    f(T<V2>{});
}

void foo()
{
    E<-1.0, -2.0>();
}

int main(int, char**) {return 0;}

New example's error output:

Using built-in specs.
COLLECT_GCC=/opt/compiler-explorer/gcc-snapshot/bin/g++
Target: x86_64-linux-gnu
Configured with: ../gcc-trunk-20210426/configure
--prefix=/opt/compiler-explorer/gcc-build/staging --build=x86_64-linux-gnu
--host=x86_64-linux-gnu --target=x86_64-linux-gnu --disable-bootstrap
--enable-multiarch --with-abi=m64 --with-multilib-list=m32,m64,mx32
--enable-multilib --enable-clocale=gnu --enable-languages=c,c++,fortran,ada,d
--enable-ld=yes --enable-gold=yes --enable-libstdcxx-debug
--enable-libstdcxx-time=yes --enable-linker-build-id --enable-lto
--enable-plugins --enable-threads=posix
--with-pkgversion=Compiler-Explorer-Build
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 12.0.0 20210425 (experimental) (Compiler-Explorer-Build) 
COLLECT_GCC_OPTIONS='-fdiagnostics-color=always' '-g' '-o' '/app/output.s'
'-masm=intel' '-S' '-std=c++20' '-v' '-save-temps' '-Wall' '-Wextra'
'-fno-strict-aliasing' '-fwrapv' '-fno-aggressive-loop-optimizations'
'-shared-libgcc' '-mtune=generic' '-march=x86-64' '-dumpdir' '/app/'

/opt/compiler-explorer/gcc-trunk-20210426/bin/../libexec/gcc/x86_64-linux-gnu/12.0.0/cc1plus
-E -quiet -v -imultiarch x86_64-linux-gnu -iprefix
/opt/compiler-explorer/gcc-trunk-20210426/bin/../lib/gcc/x86_64-linux-gnu/12.0.0/
-D_GNU_SOURCE <source> -masm=intel -mtune=generic -march=x86-64 -std=c++20
-Wall -Wextra -fdiagnostics-color=always -fno-strict-aliasing -fwrapv
-fno-aggressive-loop-optimizations -g -fworking-directory -fpch-preprocess -o
/app/output.ii
ignoring nonexistent directory
"/opt/compiler-explorer/gcc-trunk-20210426/bin/../lib/gcc/x86_64-linux-gnu/12.0.0/../../../../x86_64-linux-gnu/include"
ignoring duplicate directory
"/opt/compiler-explorer/gcc-trunk-20210426/bin/../lib/gcc/../../lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0"
ignoring duplicate directory
"/opt/compiler-explorer/gcc-trunk-20210426/bin/../lib/gcc/../../lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/x86_64-linux-gnu"
ignoring duplicate directory
"/opt/compiler-explorer/gcc-trunk-20210426/bin/../lib/gcc/../../lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/backward"
ignoring duplicate directory
"/opt/compiler-explorer/gcc-trunk-20210426/bin/../lib/gcc/../../lib/gcc/x86_64-linux-gnu/12.0.0/include"
ignoring nonexistent directory "/usr/local/include/x86_64-linux-gnu"
ignoring duplicate directory
"/opt/compiler-explorer/gcc-trunk-20210426/bin/../lib/gcc/../../lib/gcc/x86_64-linux-gnu/12.0.0/include-fixed"
ignoring nonexistent directory
"/opt/compiler-explorer/gcc-trunk-20210426/bin/../lib/gcc/../../lib/gcc/x86_64-linux-gnu/12.0.0/../../../../x86_64-linux-gnu/include"
#include "..." search starts here:
#include <...> search starts here:

/opt/compiler-explorer/gcc-trunk-20210426/bin/../lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0

/opt/compiler-explorer/gcc-trunk-20210426/bin/../lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/x86_64-linux-gnu

/opt/compiler-explorer/gcc-trunk-20210426/bin/../lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/backward

/opt/compiler-explorer/gcc-trunk-20210426/bin/../lib/gcc/x86_64-linux-gnu/12.0.0/include

/opt/compiler-explorer/gcc-trunk-20210426/bin/../lib/gcc/x86_64-linux-gnu/12.0.0/include-fixed
 /usr/local/include
 /opt/compiler-explorer/gcc-trunk-20210426/bin/../lib/gcc/../../include
 /usr/include/x86_64-linux-gnu
 /usr/include
End of search list.
COLLECT_GCC_OPTIONS='-fdiagnostics-color=always' '-g' '-o' '/app/output.s'
'-masm=intel' '-S' '-std=c++20' '-v' '-save-temps' '-Wall' '-Wextra'
'-fno-strict-aliasing' '-fwrapv' '-fno-aggressive-loop-optimizations'
'-shared-libgcc' '-mtune=generic' '-march=x86-64' '-dumpdir' '/app/'

/opt/compiler-explorer/gcc-trunk-20210426/bin/../libexec/gcc/x86_64-linux-gnu/12.0.0/cc1plus
-fpreprocessed /app/output.ii -quiet -dumpdir /app/ -dumpbase output.cpp
-dumpbase-ext .cpp -masm=intel -mtune=generic -march=x86-64 -g -Wall -Wextra
-std=c++20 -version -fdiagnostics-color=always -fno-strict-aliasing -fwrapv
-fno-aggressive-loop-optimizations -o /app/output.s
GNU C++20 (Compiler-Explorer-Build) version 12.0.0 20210425 (experimental)
(x86_64-linux-gnu)
        compiled by GNU C version 7.5.0, GMP version 6.1.0, MPFR version 3.1.4,
MPC version 1.0.3, isl version isl-0.18-GMP

GGC heuristics: --param ggc-min-expand=30 --param ggc-min-heapsize=4096
GNU C++20 (Compiler-Explorer-Build) version 12.0.0 20210425 (experimental)
(x86_64-linux-gnu)
        compiled by GNU C version 7.5.0, GMP version 6.1.0, MPFR version 3.1.4,
MPC version 1.0.3, isl version isl-0.18-GMP

GGC heuristics: --param ggc-min-expand=30 --param ggc-min-heapsize=4096
Compiler executable checksum: d98c31982476edc90c9c0027eb63ad59
<source>:18:33: error: Two symbols with same comdat_group are not linked by the
same_comdat_group list.
   18 | int main(int, char**) {return 0;}
      |                                 ^
_Z1fILdffffffff00000000EEv1TIXT_EE/4 (void f(T<X>) [with auto X = -2.0e+0])
@0x7fb785007660
  Type: function definition analyzed
  Visibility: no_reorder public weak comdat
comdat_group:_Z1fILdffffffff00000000EEv1TIXT_EE one_only
  previous sharing asm name: 3
  References: 
  Referring: 
  Function flags: body
  Called by: _Z1EILdffffffff00000000ELdffffffff00000000EEvv/2 
  Calls: 
_Z1fILdffffffff00000000EEv1TIXT_EE/3 (void f(T<X>) [with auto X = -1.0e+0])
@0x7fb785007550
  Type: function definition analyzed
  Visibility: no_reorder public weak comdat
comdat_group:_Z1fILdffffffff00000000EEv1TIXT_EE one_only
  next sharing asm name: 4
  References: 
  Referring: 
  Function flags: body
  Called by: _Z1EILdffffffff00000000ELdffffffff00000000EEvv/2 
  Calls: 
<source>:18:33: internal compiler error: symtab_node::verify failed
0x1cfe7f9 internal_error(char const*, ...)
        ???:0
0xb37622 symtab_node::verify_symtab_nodes()
        ???:0
0xb5398f symbol_table::finalize_compilation_unit()
        ???:0
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <https://gcc.gnu.org/bugs/> for instructions.
ASM generation compiler returned: 1
Using built-in specs.
COLLECT_GCC=/opt/compiler-explorer/gcc-snapshot/bin/g++
COLLECT_LTO_WRAPPER=/opt/compiler-explorer/gcc-trunk-20210426/bin/../libexec/gcc/x86_64-linux-gnu/12.0.0/lto-wrapper
Target: x86_64-linux-gnu
Configured with: ../gcc-trunk-20210426/configure
--prefix=/opt/compiler-explorer/gcc-build/staging --build=x86_64-linux-gnu
--host=x86_64-linux-gnu --target=x86_64-linux-gnu --disable-bootstrap
--enable-multiarch --with-abi=m64 --with-multilib-list=m32,m64,mx32
--enable-multilib --enable-clocale=gnu --enable-languages=c,c++,fortran,ada,d
--enable-ld=yes --enable-gold=yes --enable-libstdcxx-debug
--enable-libstdcxx-time=yes --enable-linker-build-id --enable-lto
--enable-plugins --enable-threads=posix
--with-pkgversion=Compiler-Explorer-Build
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 12.0.0 20210425 (experimental) (Compiler-Explorer-Build) 
COLLECT_GCC_OPTIONS='-fdiagnostics-color=always' '-g' '-o' '/app/output.s'
'-L.' '-std=c++20' '-v' '-save-temps' '-Wall' '-Wextra' '-fno-strict-aliasing'
'-fwrapv' '-fno-aggressive-loop-optimizations' '-shared-libgcc'
'-mtune=generic' '-march=x86-64' '-dumpdir' '/app/output.s-'

/opt/compiler-explorer/gcc-trunk-20210426/bin/../libexec/gcc/x86_64-linux-gnu/12.0.0/cc1plus
-E -quiet -v -imultiarch x86_64-linux-gnu -iprefix
/opt/compiler-explorer/gcc-trunk-20210426/bin/../lib/gcc/x86_64-linux-gnu/12.0.0/
-D_GNU_SOURCE <source> -mtune=generic -march=x86-64 -std=c++20 -Wall -Wextra
-fdiagnostics-color=always -fno-strict-aliasing -fwrapv
-fno-aggressive-loop-optimizations -g -fworking-directory -fpch-preprocess -o
/app/output.s-example.ii
ignoring nonexistent directory
"/opt/compiler-explorer/gcc-trunk-20210426/bin/../lib/gcc/x86_64-linux-gnu/12.0.0/../../../../x86_64-linux-gnu/include"
ignoring duplicate directory
"/opt/compiler-explorer/gcc-trunk-20210426/bin/../lib/gcc/../../lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0"
ignoring duplicate directory
"/opt/compiler-explorer/gcc-trunk-20210426/bin/../lib/gcc/../../lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/x86_64-linux-gnu"
ignoring duplicate directory
"/opt/compiler-explorer/gcc-trunk-20210426/bin/../lib/gcc/../../lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/backward"
ignoring duplicate directory
"/opt/compiler-explorer/gcc-trunk-20210426/bin/../lib/gcc/../../lib/gcc/x86_64-linux-gnu/12.0.0/include"
ignoring nonexistent directory "/usr/local/include/x86_64-linux-gnu"
ignoring duplicate directory
"/opt/compiler-explorer/gcc-trunk-20210426/bin/../lib/gcc/../../lib/gcc/x86_64-linux-gnu/12.0.0/include-fixed"
ignoring nonexistent directory
"/opt/compiler-explorer/gcc-trunk-20210426/bin/../lib/gcc/../../lib/gcc/x86_64-linux-gnu/12.0.0/../../../../x86_64-linux-gnu/include"
#include "..." search starts here:
#include <...> search starts here:

/opt/compiler-explorer/gcc-trunk-20210426/bin/../lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0

/opt/compiler-explorer/gcc-trunk-20210426/bin/../lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/x86_64-linux-gnu

/opt/compiler-explorer/gcc-trunk-20210426/bin/../lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/backward

/opt/compiler-explorer/gcc-trunk-20210426/bin/../lib/gcc/x86_64-linux-gnu/12.0.0/include

/opt/compiler-explorer/gcc-trunk-20210426/bin/../lib/gcc/x86_64-linux-gnu/12.0.0/include-fixed
 /usr/local/include
 /opt/compiler-explorer/gcc-trunk-20210426/bin/../lib/gcc/../../include
 /usr/include/x86_64-linux-gnu
 /usr/include
End of search list.
COLLECT_GCC_OPTIONS='-fdiagnostics-color=always' '-g' '-o' '/app/output.s'
'-L.' '-std=c++20' '-v' '-save-temps' '-Wall' '-Wextra' '-fno-strict-aliasing'
'-fwrapv' '-fno-aggressive-loop-optimizations' '-shared-libgcc'
'-mtune=generic' '-march=x86-64' '-dumpdir' '/app/output.s-'

/opt/compiler-explorer/gcc-trunk-20210426/bin/../libexec/gcc/x86_64-linux-gnu/12.0.0/cc1plus
-fpreprocessed /app/output.s-example.ii -quiet -dumpdir /app/output.s-
-dumpbase example.cpp -dumpbase-ext .cpp -mtune=generic -march=x86-64 -g -Wall
-Wextra -std=c++20 -version -fdiagnostics-color=always -fno-strict-aliasing
-fwrapv -fno-aggressive-loop-optimizations -o /app/output.s-example.s
GNU C++20 (Compiler-Explorer-Build) version 12.0.0 20210425 (experimental)
(x86_64-linux-gnu)
        compiled by GNU C version 7.5.0, GMP version 6.1.0, MPFR version 3.1.4,
MPC version 1.0.3, isl version isl-0.18-GMP

GGC heuristics: --param ggc-min-expand=30 --param ggc-min-heapsize=4096
GNU C++20 (Compiler-Explorer-Build) version 12.0.0 20210425 (experimental)
(x86_64-linux-gnu)
        compiled by GNU C version 7.5.0, GMP version 6.1.0, MPFR version 3.1.4,
MPC version 1.0.3, isl version isl-0.18-GMP

GGC heuristics: --param ggc-min-expand=30 --param ggc-min-heapsize=4096
Compiler executable checksum: d98c31982476edc90c9c0027eb63ad59
<source>:18:33: error: Two symbols with same comdat_group are not linked by the
same_comdat_group list.
   18 | int main(int, char**) {return 0;}
      |                                 ^
_Z1fILdffffffff00000000EEv1TIXT_EE/4 (void f(T<X>) [with auto X = -2.0e+0])
@0x7f202ca39660
  Type: function definition analyzed
  Visibility: no_reorder public weak comdat
comdat_group:_Z1fILdffffffff00000000EEv1TIXT_EE one_only
  previous sharing asm name: 3
  References: 
  Referring: 
  Function flags: body
  Called by: _Z1EILdffffffff00000000ELdffffffff00000000EEvv/2 
  Calls: 
_Z1fILdffffffff00000000EEv1TIXT_EE/3 (void f(T<X>) [with auto X = -1.0e+0])
@0x7f202ca39550
  Type: function definition analyzed
  Visibility: no_reorder public weak comdat
comdat_group:_Z1fILdffffffff00000000EEv1TIXT_EE one_only
  next sharing asm name: 4
  References: 
  Referring: 
  Function flags: body
  Called by: _Z1EILdffffffff00000000ELdffffffff00000000EEvv/2 
  Calls: 
<source>:18:33: internal compiler error: symtab_node::verify failed
0x1cfe7f9 internal_error(char const*, ...)
        ???:0
0xb37622 symtab_node::verify_symtab_nodes()
        ???:0
0xb5398f symbol_table::finalize_compilation_unit()
        ???:0
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <https://gcc.gnu.org/bugs/> for instructions.
Execution build compiler returned: 1

[Bug c++/100279] [ICE in trunk] ICE caused by negative double NTTP. Error: Two symbols with same comdat_group are not linked by the same_comdat_group list.

[bobmiller at nvidia dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100279

--- Comment #3 from Bob Miller <bobmiller at nvidia dot com> ---
Further minimized example. Same ICE. 
ICE is visible here: https://godbolt.org/z/o7M9nYYYE

template<auto V> struct T {};

template<auto X>
void f(T<X>) {}

int main(int, char**) 
{
    f(T<-1.0>{});
    f(T<-2.0>{});
    return 0;
}

[Bug c++/100279] [ICE in trunk] ICE caused by negative double NTTP. Error: Two symbols with same comdat_group are not linked by the same_comdat_group list.

[ppalka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100279

Patrick Palka <ppalka at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
                 CC|                            |ppalka at gcc dot gnu.org
   Last reconfirmed|                            |2021-04-27
     Ever confirmed|0                           |1
           See Also|                            |https://gcc.gnu.org/bugzill
                   |                            |a/show_bug.cgi?id=98216

--- Comment #4 from Patrick Palka <ppalka at gcc dot gnu.org> ---
Confirmed, seems closely related to PR98216.

[Bug c++/100279] [ICE in trunk] ICE caused by negative double NTTP. Error: Two symbols with same comdat_group are not linked by the same_comdat_group list.

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100279

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

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

--- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
This is the same as PR 98216.

*** This bug has been marked as a duplicate of bug 98216 ***