https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95028

            Bug ID: 95028
           Summary: ICE in g++ (Arch Linux 9.3.0-1) 9.3.0 with captured
                    OMP reduce clause in lambda
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: fytch at protonmail dot com
  Target Milestone: ---

Created attachment 48491
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=48491&action=edit
Code that causes the ICE (same as in the comment)

Description:
GCC seems to crash when writing this OpenMP clause within a lambda. Writing the
loop outside the lambda is fine and defining the variable sum inside the lambda
is also fine but this combination seems to crash GCC.

Code:
int main() {
    double sum;
    const auto task = [&] {
        #pragma omp parallel for reduction(+: sum)
        for(int i = 0; i < 1; ++i)
            sum += 1;
    };
    task();
}

Compiled with:
g++ main.cpp -fopenmp

Output:
during RTL pass: expand
main.cpp: In lambda function:
main.cpp:4:17: internal compiler error: in make_decl_rtl, at varasm.c:1340
    4 |         #pragma omp parallel for reduction(+: sum)
      |                 ^~~
Please submit a full bug report,
with preprocessed source if appropriate.
See <https://bugs.archlinux.org/> for instructions.

Output of g++ -v:
Using built-in specs.
COLLECT_GCC=g++
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-pc-linux-gnu/9.3.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: /build/gcc/src/gcc/configure --prefix=/usr --libdir=/usr/lib
--libexecdir=/usr/lib --mandir=/usr/share/man --infodir=/usr/share/info
--with-pkgversion='Arch Linux 9.3.0-1'
--with-bugurl=https://bugs.archlinux.org/
--enable-languages=c,c++,ada,fortran,go,lto,objc,obj-c++,d --enable-shared
--enable-threads=posix --with-system-zlib --with-isl --enable-__cxa_atexit
--disable-libunwind-exceptions --enable-clocale=gnu --disable-libstdcxx-pch
--disable-libssp --enable-gnu-unique-object --enable-linker-build-id
--enable-lto --enable-plugin --enable-install-libiberty
--with-linker-hash-style=gnu --enable-gnu-indirect-function --enable-multilib
--disable-werror --enable-checking=release --enable-default-pie
--enable-default-ssp --enable-cet=auto gdc_include_dir=/usr/include/dlang/gdc
Thread model: posix
gcc version 9.3.0 (Arch Linux 9.3.0-1)

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