Building LLVM 20.1.4 fails with C++20

[fawltylanguage]

FAILED: lib/ExecutionEngine/JITLink/CMakeFiles/LLVMJITLink.dir/MachO_arm64.cpp.o
/scratch/devel/bin/clang++ -DGTEST_HAS_RTTI=0 -DLLVM_EXPORTS -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -I/scratch/build/libs/llvm/build/lib/ExecutionEngine/JITLink -I/scratch/build/libs/llvm/llvm-project-20.1.4.src/llvm/lib/ExecutionEngine/JITLink -I/scratch/build/libs/llvm/build/include -I/scratch/build/libs/llvm/llvm-project-20.1.4.src/llvm/include -isystem /scratch/devel/include -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -Werror=date-time -Werror=unguarded-availability-new -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wmissing-field-initializers -pedantic -Wno-long-long -Wc++98-compat-extra-semi -Wimplicit-fallthrough -Wcovered-switch-default -Wno-noexcept-type -Wnon-virtual-dtor -Wdelete-non-virtual-dtor -Wsuggest-override -Wstring-conversion -Wmisleading-indentation -Wctad-maybe-unsupported -fdiagnostics-color -ffunction-sections -fdata-sections -O3 -DNDEBUG -std=c++20  -fno-exceptions -funwind-tables -fno-rtti -MD -MT lib/ExecutionEngine/JITLink/CMakeFiles/LLVMJITLink.dir/MachO_arm64.cpp.o -MF lib/ExecutionEngine/JITLink/CMakeFiles/LLVMJITLink.dir/MachO_arm64.cpp.o.d -o lib/ExecutionEngine/JITLink/CMakeFiles/LLVMJITLink.dir/MachO_arm64.cpp.o -c /scratch/build/libs/llvm/llvm-project-20.1.4.src/llvm/lib/ExecutionEngine/JITLink/MachO_arm64.cpp
In file included from /scratch/build/libs/llvm/llvm-project-20.1.4.src/llvm/lib/ExecutionEngine/JITLink/MachO_arm64.cpp:13:
In file included from /scratch/build/libs/llvm/llvm-project-20.1.4.src/llvm/include/llvm/ExecutionEngine/JITLink/MachO_arm64.h:16:
In file included from /scratch/build/libs/llvm/llvm-project-20.1.4.src/llvm/include/llvm/ExecutionEngine/JITLink/JITLink.h:18:
In file included from /scratch/build/libs/llvm/llvm-project-20.1.4.src/llvm/include/llvm/ADT/FunctionExtras.h:36:
In file included from /scratch/build/libs/llvm/llvm-project-20.1.4.src/llvm/include/llvm/ADT/PointerUnion.h:20:
In file included from /scratch/build/libs/llvm/llvm-project-20.1.4.src/llvm/include/llvm/ADT/STLExtras.h:24:
/scratch/build/libs/llvm/llvm-project-20.1.4.src/llvm/include/llvm/ADT/iterator.h:272:9: error: static assertion failed due to requirement 'iterator_facade_base<llvm::mapped_iterator<llvm::StringMapIterator<llvm::jitlink::Symbol *>, llvm::jitlink::LinkGraph::GetExternalSymbolMapEntryValue, llvm::jitlink::Symbol *>, std::forward_iterator_tag, llvm::jitlink::Symbol *, long, llvm::jitlink::Symbol **, llvm::jitlink::Symbol *>::IsRandomAccess': The '-' operator is only defined for random access iterators.
  272 |         BaseT::IsRandomAccess,
      |         ^~~~~~~~~~~~~~~~~~~~~
/scratch/devel/bin/../lib64/gcc/x86_64-pc-linux-gnu/15.1.1/../../../../include/c++/15.1.1/bits/ranges_base.h:976:23: note: in instantiation of member function 'llvm::iterator_adaptor_base<llvm::mapped_iterator<llvm::StringMapIterator<llvm::jitlink::Symbol *>, llvm::jitlink::LinkGraph::GetExternalSymbolMapEntryValue>, llvm::StringMapIterator<llvm::jitlink::Symbol *>, std::forward_iterator_tag, llvm::jitlink::Symbol *, long, llvm::jitlink::Symbol **, llvm::jitlink::Symbol *>::operator-' requested here
  976 |       { return __last - static_cast<const decay_t<_It>&>(__first); }
      |                       ^
In file included from /scratch/build/libs/llvm/llvm-project-20.1.4.src/llvm/lib/ExecutionEngine/JITLink/MachO_arm64.cpp:13:
In file included from /scratch/build/libs/llvm/llvm-project-20.1.4.src/llvm/include/llvm/ExecutionEngine/JITLink/MachO_arm64.h:16:
In file included from /scratch/build/libs/llvm/llvm-project-20.1.4.src/llvm/include/llvm/ExecutionEngine/JITLink/JITLink.h:18:
In file included from /scratch/build/libs/llvm/llvm-project-20.1.4.src/llvm/include/llvm/ADT/FunctionExtras.h:36:
In file included from /scratch/build/libs/llvm/llvm-project-20.1.4.src/llvm/include/llvm/ADT/PointerUnion.h:20:
In file included from /scratch/build/libs/llvm/llvm-project-20.1.4.src/llvm/include/llvm/ADT/STLExtras.h:24:
/scratch/build/libs/llvm/llvm-project-20.1.4.src/llvm/include/llvm/ADT/iterator.h:274:14: error: invalid operands to binary expression ('const llvm::StringMapIterator<llvm::jitlink::Symbol *>' and 'const llvm::StringMapIterator<llvm::jitlink::Symbol *>')
  274 |     return I - RHS.I;
      |            ~ ^ ~~~~~
/scratch/build/libs/llvm/llvm-project-20.1.4.src/llvm/include/llvm/ADT/APInt.h:2182:14: note: candidate function not viable: no known conversion from 'const llvm::StringMapIterator<llvm::jitlink::Symbol *>' to 'APInt' for 1st argument
 2182 | inline APInt operator-(APInt a, const APInt &b) {
      |              ^         ~~~~~~~
/scratch/build/libs/llvm/llvm-project-20.1.4.src/llvm/include/llvm/ADT/APInt.h:2187:14: note: candidate function not viable: no known conversion from 'const llvm::StringMapIterator<llvm::jitlink::Symbol *>' to 'const APInt' for 1st argument
 2187 | inline APInt operator-(const APInt &a, APInt &&b) {
      |              ^         ~~~~~~~~~~~~~~
/scratch/build/libs/llvm/llvm-project-20.1.4.src/llvm/include/llvm/ADT/APInt.h:2193:14: note: candidate function not viable: no known conversion from 'const llvm::StringMapIterator<llvm::jitlink::Symbol *>' to 'APInt' for 1st argument
 2193 | inline APInt operator-(APInt a, uint64_t RHS) {
      |              ^         ~~~~~~~
/scratch/build/libs/llvm/llvm-project-20.1.4.src/llvm/include/llvm/ADT/APInt.h:2198:14: note: candidate function not viable: no known conversion from 'const llvm::StringMapIterator<llvm::jitlink::Symbol *>' to 'uint64_t' (aka 'unsigned long') for 1st argument
 2198 | inline APInt operator-(uint64_t LHS, APInt b) {
      |              ^         ~~~~~~~~~~~~
/scratch/build/libs/llvm/llvm-project-20.1.4.src/llvm/include/llvm/ADT/iterator.h:145:12: note: candidate function not viable: no known conversion from 'const llvm::StringMapIterator<llvm::jitlink::Symbol *>' to 'long' for 1st argument
  145 |   DerivedT operator-(DifferenceTypeT n) const {
      |            ^         ~~~~~~~~~~~~~~~~~
/scratch/build/libs/llvm/llvm-project-20.1.4.src/llvm/include/llvm/ADT/APInt.h:2157:14: note: candidate function not viable: requires single argument 'v', but 2 arguments were provided
 2157 | inline APInt operator-(APInt v) {
      |              ^         ~~~~~~~


clang++ -v:
clang version 20.1.0
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /scratch/devel/bin
Found candidate GCC installation: /scratch/devel/bin/../lib/gcc/x86_64-pc-linux-gnu/15.0.1
Found candidate GCC installation: /scratch/devel/bin/../lib/gcc/x86_64-pc-linux-gnu/15.1.1
Found candidate GCC installation: /scratch/devel/bin/../lib64/gcc/x86_64-pc-linux-gnu/15.0.1
Found candidate GCC installation: /scratch/devel/bin/../lib64/gcc/x86_64-pc-linux-gnu/15.1.1
Selected GCC installation: /scratch/devel/bin/../lib64/gcc/x86_64-pc-linux-gnu/15.1.1
Candidate multilib: .;@m64
Selected multilib: .;@m64

[llvmbot]

@llvm/issue-subscribers-jitlink

Author: None (fawltylanguage)

``` FAILED: lib/ExecutionEngine/JITLink/CMakeFiles/LLVMJITLink.dir/MachO_arm64.cpp.o /scratch/devel/bin/clang++ -DGTEST_HAS_RTTI=0 -DLLVM_EXPORTS -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -I/scratch/build/libs/llvm/build/lib/ExecutionEngine/JITLink -I/scratch/build/libs/llvm/llvm-project-20.1.4.src/llvm/lib/ExecutionEngine/JITLink -I/scratch/build/libs/llvm/build/include -I/scratch/build/libs/llvm/llvm-project-20.1.4.src/llvm/include -isystem /scratch/devel/include -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -Werror=date-time -Werror=unguarded-availability-new -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wmissing-field-initializers -pedantic -Wno-long-long -Wc++98-compat-extra-semi -Wimplicit-fallthrough -Wcovered-switch-default -Wno-noexcept-type -Wnon-virtual-dtor -Wdelete-non-virtual-dtor -Wsuggest-override -Wstring-conversion -Wmisleading-indentation -Wctad-maybe-unsupported -fdiagnostics-color -ffunction-sections -fdata-sections -O3 -DNDEBUG -std=c++20 -fno-exceptions -funwind-tables -fno-rtti -MD -MT lib/ExecutionEngine/JITLink/CMakeFiles/LLVMJITLink.dir/MachO_arm64.cpp.o -MF lib/ExecutionEngine/JITLink/CMakeFiles/LLVMJITLink.dir/MachO_arm64.cpp.o.d -o lib/ExecutionEngine/JITLink/CMakeFiles/LLVMJITLink.dir/MachO_arm64.cpp.o -c /scratch/build/libs/llvm/llvm-project-20.1.4.src/llvm/lib/ExecutionEngine/JITLink/MachO_arm64.cpp In file included from /scratch/build/libs/llvm/llvm-project-20.1.4.src/llvm/lib/ExecutionEngine/JITLink/MachO_arm64.cpp:13: In file included from /scratch/build/libs/llvm/llvm-project-20.1.4.src/llvm/include/llvm/ExecutionEngine/JITLink/MachO_arm64.h:16: In file included from /scratch/build/libs/llvm/llvm-project-20.1.4.src/llvm/include/llvm/ExecutionEngine/JITLink/JITLink.h:18: In file included from /scratch/build/libs/llvm/llvm-project-20.1.4.src/llvm/include/llvm/ADT/FunctionExtras.h:36: In file included from /scratch/build/libs/llvm/llvm-project-20.1.4.src/llvm/include/llvm/ADT/PointerUnion.h:20: In file included from /scratch/build/libs/llvm/llvm-project-20.1.4.src/llvm/include/llvm/ADT/STLExtras.h:24: /scratch/build/libs/llvm/llvm-project-20.1.4.src/llvm/include/llvm/ADT/iterator.h:272:9: error: static assertion failed due to requirement 'iterator_facade_base<llvm::mapped_iterator<llvm::StringMapIterator<llvm::jitlink::Symbol *>, llvm::jitlink::LinkGraph::GetExternalSymbolMapEntryValue, llvm::jitlink::Symbol *>, std::forward_iterator_tag, llvm::jitlink::Symbol *, long, llvm::jitlink::Symbol **, llvm::jitlink::Symbol *>::IsRandomAccess': The '-' operator is only defined for random access iterators. 272 | BaseT::IsRandomAccess, | ^~~~~~~~~~~~~~~~~~~~~ /scratch/devel/bin/../lib64/gcc/x86_64-pc-linux-gnu/15.1.1/../../../../include/c++/15.1.1/bits/ranges_base.h:976:23: note: in instantiation of member function 'llvm::iterator_adaptor_base<llvm::mapped_iterator<llvm::StringMapIterator<llvm::jitlink::Symbol *>, llvm::jitlink::LinkGraph::GetExternalSymbolMapEntryValue>, llvm::StringMapIterator<llvm::jitlink::Symbol *>, std::forward_iterator_tag, llvm::jitlink::Symbol *, long, llvm::jitlink::Symbol **, llvm::jitlink::Symbol *>::operator-' requested here 976 | { return __last - static_cast<const decay_t<_It>&>(__first); } | ^ In file included from /scratch/build/libs/llvm/llvm-project-20.1.4.src/llvm/lib/ExecutionEngine/JITLink/MachO_arm64.cpp:13: In file included from /scratch/build/libs/llvm/llvm-project-20.1.4.src/llvm/include/llvm/ExecutionEngine/JITLink/MachO_arm64.h:16: In file included from /scratch/build/libs/llvm/llvm-project-20.1.4.src/llvm/include/llvm/ExecutionEngine/JITLink/JITLink.h:18: In file included from /scratch/build/libs/llvm/llvm-project-20.1.4.src/llvm/include/llvm/ADT/FunctionExtras.h:36: In file included from /scratch/build/libs/llvm/llvm-project-20.1.4.src/llvm/include/llvm/ADT/PointerUnion.h:20: In file included from /scratch/build/libs/llvm/llvm-project-20.1.4.src/llvm/include/llvm/ADT/STLExtras.h:24: /scratch/build/libs/llvm/llvm-project-20.1.4.src/llvm/include/llvm/ADT/iterator.h:274:14: error: invalid operands to binary expression ('const llvm::StringMapIterator<llvm::jitlink::Symbol *>' and 'const llvm::StringMapIterator<llvm::jitlink::Symbol *>') 274 | return I - RHS.I; | ~ ^ ~~~~~ /scratch/build/libs/llvm/llvm-project-20.1.4.src/llvm/include/llvm/ADT/APInt.h:2182:14: note: candidate function not viable: no known conversion from 'const llvm::StringMapIterator<llvm::jitlink::Symbol *>' to 'APInt' for 1st argument 2182 | inline APInt operator-(APInt a, const APInt &b) { | ^ ~~~~~~~ /scratch/build/libs/llvm/llvm-project-20.1.4.src/llvm/include/llvm/ADT/APInt.h:2187:14: note: candidate function not viable: no known conversion from 'const llvm::StringMapIterator<llvm::jitlink::Symbol *>' to 'const APInt' for 1st argument 2187 | inline APInt operator-(const APInt &a, APInt &&b) { | ^ ~~~~~~~~~~~~~~ /scratch/build/libs/llvm/llvm-project-20.1.4.src/llvm/include/llvm/ADT/APInt.h:2193:14: note: candidate function not viable: no known conversion from 'const llvm::StringMapIterator<llvm::jitlink::Symbol *>' to 'APInt' for 1st argument 2193 | inline APInt operator-(APInt a, uint64_t RHS) { | ^ ~~~~~~~ /scratch/build/libs/llvm/llvm-project-20.1.4.src/llvm/include/llvm/ADT/APInt.h:2198:14: note: candidate function not viable: no known conversion from 'const llvm::StringMapIterator<llvm::jitlink::Symbol *>' to 'uint64_t' (aka 'unsigned long') for 1st argument 2198 | inline APInt operator-(uint64_t LHS, APInt b) { | ^ ~~~~~~~~~~~~ /scratch/build/libs/llvm/llvm-project-20.1.4.src/llvm/include/llvm/ADT/iterator.h:145:12: note: candidate function not viable: no known conversion from 'const llvm::StringMapIterator<llvm::jitlink::Symbol *>' to 'long' for 1st argument 145 | DerivedT operator-(DifferenceTypeT n) const { | ^ ~~~~~~~~~~~~~~~~~ /scratch/build/libs/llvm/llvm-project-20.1.4.src/llvm/include/llvm/ADT/APInt.h:2157:14: note: candidate function not viable: requires single argument 'v', but 2 arguments were provided 2157 | inline APInt operator-(APInt v) { | ^ ~~~~~~~

clang++ -v:
clang version 20.1.0
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /scratch/devel/bin
Found candidate GCC installation: /scratch/devel/bin/../lib/gcc/x86_64-pc-linux-gnu/15.0.1
Found candidate GCC installation: /scratch/devel/bin/../lib/gcc/x86_64-pc-linux-gnu/15.1.1
Found candidate GCC installation: /scratch/devel/bin/../lib64/gcc/x86_64-pc-linux-gnu/15.0.1
Found candidate GCC installation: /scratch/devel/bin/../lib64/gcc/x86_64-pc-linux-gnu/15.1.1
Selected GCC installation: /scratch/devel/bin/../lib64/gcc/x86_64-pc-linux-gnu/15.1.1
Candidate multilib: .;@m64
Selected multilib: .;@m64

</details>

[lhames]

There haven't been any changes to this code recently. Is this a new build config?

[fawltylanguage]

There haven't been any changes to this code recently. Is this a new build config?

Yes, it is.

I have found the culprit: -DCMAKE_CXX_STANDARD=20. With 17, it works.

[frederick-vs-ja]

It seems that external_symbol_iterator accidentally satisfies sized_sentinel_for<external_symbol_iterator> and libstdc++ starts to use ranges::distance since C++20, where a wrong overload is selected and the ill-formed operator- is called.

[jcalvinowens]

I've also been running into this building llvm-20.1.5 on a gcc-15 Linux system with CMAKE_CXX_STANDARD=20. I think the issue is actually in libstdc++, I set up a bisect to run overnight and it landed here: gcc-mirror/gcc@3abe751

Both g++ and clang++ emit the same error (exactly what is linked above). On a gcc-14 and llvm/libcxx/musl systems, I can successfully build llvm-20.1.5 with CMAKE_CXX_STANDARD=20. I cannot claim to understand the gory C++ language details here, but all signs point to that libstdc++ change being the root problem :)

I requested an account on the GCC bugzilla, when that goes through I'll file a bug.

# bad: [1b306039ac49f8ad91ca71d3de3150a3c9fa792a] Update ChangeLog and version files for release
# good: [04696df09633baf97cdbbdd6e9929b9d472161d3] Update ChangeLog and version files for release
git bisect start 'releases/gcc-15.1.0' 'releases/gcc-14.2.0'
# good: [b8e9fd535d6093e3a24af858364d8517a767b0d7] amdgcn: Add gfx90c target
git bisect good b8e9fd535d6093e3a24af858364d8517a767b0d7
# bad: [acba8b3d8dec0124c8b3a7e112b3a784a5091214] [PATCH] Fix SLP when ifcvt versioned loop is not vectorized
git bisect bad acba8b3d8dec0124c8b3a7e112b3a784a5091214
# good: [f9c7775f58798a051b57356ad321b758a2ee837d] xtensa: Make use of scaled [U]FLOAT/TRUNC.S instructions
git bisect good f9c7775f58798a051b57356ad321b758a2ee837d
# good: [323291c29c77e3214f4850129bb8a3d0d8da6a45] ipa: Rename ipa_supports_p to ipa_vr_supported_type_p
git bisect good 323291c29c77e3214f4850129bb8a3d0d8da6a45
# good: [e5f5cffb8c8243896a9d3bd0e2b8f14c70f8df1e] tree-optimization/116024 - simplify C1-X cmp C2 for wrapping signed types
git bisect good e5f5cffb8c8243896a9d3bd0e2b8f14c70f8df1e
# bad: [11577659949dfd1dfb49cc14e6dcc6b394ebd8c4] gcc/: Rename array_type_nelts => array_type_nelts_minus_one
git bisect bad 11577659949dfd1dfb49cc14e6dcc6b394ebd8c4
# good: [0515b2436b7c7e5e391eae7edc42173c52bab61d] libstdc++: Constrain std::expected comparisons (P3379R0)
git bisect good 0515b2436b7c7e5e391eae7edc42173c52bab61d
# good: [c962153633048a506107a3ce13906edd19bfeb5c] doc: remove outdated C++ Concepts section
git bisect good c962153633048a506107a3ce13906edd19bfeb5c
# good: [c7f95f2b531ed179012c9bd26bbc1d2d4a849b22] arm: [MVE intrinsics] remove useless v[id]wdup expanders
git bisect good c7f95f2b531ed179012c9bd26bbc1d2d4a849b22
# good: [a1381b69b9d81f210735d4a5bc9d65a0b01d1bda] [3/n] remove fast-math-*.c special-casing of gcc.dg/vect/ files
git bisect good a1381b69b9d81f210735d4a5bc9d65a0b01d1bda
# bad: [6ecf2b380da6129cd32edccdbc322dfd2884d490] libstdc++: Add always_inline to some one-liners in <bits/stl_algobase.h>
git bisect bad 6ecf2b380da6129cd32edccdbc322dfd2884d490
# good: [2608fcfe5fcff260d62379d8f74efb9be8df70f4] libstdc++: Move std::__niter_base and std::__niter_wrap to stl_iterator.h
git bisect good 2608fcfe5fcff260d62379d8f74efb9be8df70f4
# bad: [4020ee77186d1544e8565ae5786af99b8e56543a] libstdc++: Make __normal_iterator constexpr, always_inline, nodiscard
git bisect bad 4020ee77186d1544e8565ae5786af99b8e56543a
# bad: [3abe751ea86e3472fa2c97bf2014f9f93f569019] libstdc++: Refactor std::uninitialized_{copy,fill,fill_n} algos [PR68350]
git bisect bad 3abe751ea86e3472fa2c97bf2014f9f93f569019
# first bad commit: [3abe751ea86e3472fa2c97bf2014f9f93f569019] libstdc++: Refactor std::uninitialized_{copy,fill,fill_n} algos [PR68350]

[jcalvinowens]

Well, I've been locked out of my new bugzilla account due to "inappropriate content", something about the below is tripping the abuse filters? Ugh... I'll file it when I get that fixed.

Hello all,

Building llvm-20.1.5 under the C++20 standard fails with gcc-15.1. The same LLVM source builds successfully as C++20 with gcc-14.2.

I ran an overnight git-bisect on gcc, and it landed here in libstdc++: https://github.com/gcc-mirror/gcc/commit/3abe751ea86e3472fa2c97bf2014f9f93f569019 (full bisect log is in attachments).

The two error messages from GCC are at the end of this report: the first is the message I see on the commit blamed by the bisect; the second is the error I see on the current gcc-15 release branch. Using LLVM to build itself against libstdc++ results in nearly identical errors as seen with gcc-15 (both compilers agree).

I'm building GCC as follows:

        ./configure \
                --prefix="${HOME}/gcc-bisect/" \
                --disable-multilib \
                --enable-default-pie \
                --disable-bootstrap
        BOOT_CFLAGS="-Os -pipe" make -j33 -s
        make install -s

...and building LLVM as follows:

        cmake -G Ninja \
                -DCMAKE_INSTALL_PREFIX="${HOME}/bisect-llvm-test" \
                -DCMAKE_BUILD_TYPE=Release \
                -DCMAKE_C_FLAGS="-Os -pipe" \
                -DCMAKE_C_COMPILER="${HOME}/gcc-bisect/bin/gcc" \
                -DCMAKE_CXX_FLAGS="-Os -pipe" \
                -DCMAKE_CXX_COMPILER="${HOME}/gcc-bisect/bin/g++" \
                -DCMAKE_CXX_STANDARD=20 \
                -DLLVM_ENABLE_PROJECTS=all \
                -DLLVM_ENABLE_RUNTIMES=all \
                ../llvm
        ninja all

There's an open issue on the LLVM github: https://github.com/llvm/llvm-project/issues/139072

================================================================================
First LLVM build error (building commit 3abe751ea86e3472fa2c97bf2014f9f93f569019):
================================================================================

FAILED: tools/mlir/lib/IR/CMakeFiles/obj.MLIRIR.dir/Dominance.cpp.o 
/home/calvinow/gnu/bin/g++ -DGTEST_HAS_RTTI=0 -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -I/home/calvinow/git/llvm/build/tools/mlir/lib/IR -I/home/calvinow/git/llvm/mlir/lib/IR -I/home/calvinow/git/llvm/build/tools/mlir/include -I/home/calvinow/git/llvm/mlir/include -I/home/calvinow/git/llvm/build/include -I/home/calvinow/git/llvm/llvm/include -Os -pipe -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -Werror=date-time -fno-lifetime-dse -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wno-missing-field-initializers -pedantic -Wno-long-long -Wimplicit-fallthrough -Wno-maybe-uninitialized -Wno-nonnull -Wno-class-memaccess -Wno-redundant-move -Wno-pessimizing-move -Wno-noexcept-type -Wdelete-non-virtual-dtor -Wsuggest-override -Wno-comment -Wno-misleading-indentation -Wctad-maybe-unsupported -fdiagnostics-color -ffunction-sections -fdata-sections -Wundef -O3 -DNDEBUG -std=c++20  -fno-exceptions -funwind-tables -fno-rtti -MD -MT tools/mlir/lib/IR/CMakeFiles/obj.MLIRIR.dir/Dominance.cpp.o -MF tools/mlir/lib/IR/CMakeFiles/obj.MLIRIR.dir/Dominance.cpp.o.d -o tools/mlir/lib/IR/CMakeFiles/obj.MLIRIR.dir/Dominance.cpp.o -c /home/calvinow/git/llvm/mlir/lib/IR/Dominance.cpp
In file included from /home/calvinow/git/llvm/mlir/include/mlir/IR/OperationSupport.h:23,
                 from /home/calvinow/git/llvm/mlir/include/mlir/IR/Operation.h:19,
                 from /home/calvinow/git/llvm/mlir/lib/IR/Dominance.cpp:15:
/home/calvinow/git/llvm/mlir/include/mlir/IR/TypeRange.h: In static member function ‘static bool llvm::DenseMapInfo<mlir::TypeRange>::isEqual(mlir::TypeRange, mlir::TypeRange)’:
/home/calvinow/git/llvm/mlir/include/mlir/IR/TypeRange.h:208:19: warning: C++20 says that these are ambiguous, even though the second is reversed:
  208 |     return lhs == rhs;
      |                   ^~~
In file included from /home/calvinow/git/llvm/mlir/include/mlir/Support/TypeID.h:20,
                 from /home/calvinow/git/llvm/mlir/include/mlir/IR/MLIRContext.h:13,
                 from /home/calvinow/git/llvm/mlir/include/mlir/IR/TypeSupport.h:16,
                 from /home/calvinow/git/llvm/mlir/include/mlir/IR/Types.h:12,
                 from /home/calvinow/git/llvm/mlir/include/mlir/IR/Value.h:16,
                 from /home/calvinow/git/llvm/mlir/include/mlir/IR/BlockSupport.h:16,
                 from /home/calvinow/git/llvm/mlir/include/mlir/IR/Block.h:16,
                 from /home/calvinow/git/llvm/mlir/include/mlir/IR/Region.h:16,
                 from /home/calvinow/git/llvm/mlir/include/mlir/IR/RegionGraphTraits.h:18,
                 from /home/calvinow/git/llvm/mlir/include/mlir/IR/Dominance.h:22,
                 from /home/calvinow/git/llvm/mlir/lib/IR/Dominance.cpp:14:
/home/calvinow/git/llvm/llvm/include/llvm/ADT/STLExtras.h:1367:6: note: candidate 1: ‘bool llvm::detail::operator==(const indexed_accessor_range_base<DerivedT, BaseT, T, PointerT, ReferenceT>&, const OtherT&) [with OtherT = mlir::TypeRange; DerivedT = mlir::TypeRange; BaseT = llvm::PointerUnion<const mlir::Value*, const mlir::Type*, mlir::OpOperand*, mlir::detail::OpResultImpl*>; T = mlir::Type; PointerT = mlir::Type; ReferenceT = mlir::Type]’
 1367 | bool operator==(const indexed_accessor_range_base<DerivedT, BaseT, T, PointerT,
      |      ^~~~~~~~
/home/calvinow/git/llvm/llvm/include/llvm/ADT/STLExtras.h:1367:6: note: candidate 2: ‘bool llvm::detail::operator==(const indexed_accessor_range_base<DerivedT, BaseT, T, PointerT, ReferenceT>&, const OtherT&) [with OtherT = mlir::TypeRange; DerivedT = mlir::TypeRange; BaseT = llvm::PointerUnion<const mlir::Value*, const mlir::Type*, mlir::OpOperand*, mlir::detail::OpResultImpl*>; T = mlir::Type; PointerT = mlir::Type; ReferenceT = mlir::Type]’ (reversed)
In file included from /home/calvinow/gnu/include/c++/15.0.0/type_traits:40,
                 from /home/calvinow/git/llvm/llvm/include/llvm/Support/type_traits.h:17,
                 from /home/calvinow/git/llvm/llvm/include/llvm/Support/Casting.h:18,
                 from /home/calvinow/git/llvm/mlir/include/mlir/Support/LLVM.h:23,
                 from /home/calvinow/git/llvm/mlir/include/mlir/IR/MLIRContext.h:12:
/home/calvinow/gnu/include/c++/15.0.0/bits/stl_iterator.h: In instantiation of ‘constexpr std::reverse_iterator<_Iterator>::reverse_iterator() [with _Iterator = llvm::detail::indexed_accessor_range_base<mlir::SuccessorRange, mlir::BlockOperand*, mlir::Block*, mlir::Block*, mlir::Block*>::iterator]’:
/home/calvinow/gnu/include/c++/15.0.0/type_traits:3547:46:   required from ‘constexpr const bool std::is_constructible_v<std::reverse_iterator<llvm::detail::indexed_accessor_range_base<mlir::SuccessorRange, mlir::BlockOperand*, mlir::Block*, mlir::Block*, mlir::Block*>::iterator> >’
 3547 |   inline constexpr bool is_constructible_v = __is_constructible(_Tp, _Args...);
      |                                              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/calvinow/gnu/include/c++/15.0.0/concepts:162:30:   required from ‘_ForwardIterator std::uninitialized_copy(_InputIterator, _InputIterator, _ForwardIterator) [with _InputIterator = reverse_iterator<llvm::detail::indexed_accessor_range_base<mlir::SuccessorRange, mlir::BlockOperand*, mlir::Block*, mlir::Block*, mlir::Block*>::iterator>; _ForwardIterator = mlir::Block**]’
  162 |       = destructible<_Tp> && is_constructible_v<_Tp, _Args...>;
      |                              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/calvinow/git/llvm/llvm/include/llvm/ADT/SmallVector.h:505:28:   required from ‘static void llvm::SmallVectorTemplateBase<T, true>::uninitialized_copy(It1, It1, It2) [with It1 = std::reverse_iterator<llvm::detail::indexed_accessor_range_base<mlir::SuccessorRange, mlir::BlockOperand*, mlir::Block*, mlir::Block*, mlir::Block*>::iterator>; It2 = mlir::Block**; T = mlir::Block*]’
  505 |     std::uninitialized_copy(I, E, Dest);
      |     ~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~
/home/calvinow/git/llvm/llvm/include/llvm/ADT/SmallVector.h:687:29:   required from ‘void llvm::SmallVectorImpl<T>::append(ItTy, ItTy) [with ItTy = std::reverse_iterator<llvm::detail::indexed_accessor_range_base<mlir::SuccessorRange, mlir::BlockOperand*, mlir::Block*, mlir::Block*, mlir::Block*>::iterator>; <template-parameter-2-2> = void; T = mlir::Block*]’
  687 |     this->uninitialized_copy(in_start, in_end, this->end());
      |     ~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/calvinow/git/llvm/llvm/include/llvm/ADT/SmallVector.h:1223:17:   [ skipping 2 instantiation contexts, use -ftemplate-backtrace-limit=0 to disable ]
/home/calvinow/git/llvm/llvm/include/llvm/Support/GenericDomTreeConstruction.h:114:60:   required from ‘static llvm::SmallVector<typename DomTreeT::NodePtr, 8> llvm::DomTreeBuilder::SemiNCAInfo<DomTreeT>::getChildren(NodePtr, BatchUpdatePtr) [with bool Inversed = false; DomTreeT = llvm::DominatorTreeBase<mlir::Block, false>; typename DomTreeT::NodePtr = mlir::Block*; NodePtr = mlir::Block*; BatchUpdatePtr = llvm::DomTreeBuilder::SemiNCAInfo<llvm::DominatorTreeBase<mlir::Block, false> >::BatchUpdateInfo*]’
  114 |       return BUI->PreViewCFG.template getChildren<Inversed>(N);
      |              ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~
/home/calvinow/git/llvm/llvm/include/llvm/Support/GenericDomTreeConstruction.h:793:57:   required from ‘static void llvm::DomTreeBuilder::SemiNCAInfo<DomTreeT>::InsertReachable(DomTreeT&, BatchUpdatePtr, TreeNodePtr, TreeNodePtr) [with DomTreeT = llvm::DominatorTreeBase<mlir::Block, false>; BatchUpdatePtr = llvm::DomTreeBuilder::SemiNCAInfo<llvm::DominatorTreeBase<mlir::Block, false> >::BatchUpdateInfo*; TreeNodePtr = llvm::DomTreeNodeBase<mlir::Block>*]’
  793 |         for (const NodePtr Succ : getChildren<IsPostDom>(TN->getBlock(), BUI)) {
      |                                   ~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~
/home/calvinow/git/llvm/llvm/include/llvm/Support/GenericDomTreeConstruction.h:673:22:   required from ‘static void llvm::DomTreeBuilder::SemiNCAInfo<DomTreeT>::InsertEdge(DomTreeT&, BatchUpdatePtr, NodePtr, NodePtr) [with DomTreeT = llvm::DominatorTreeBase<mlir::Block, false>; BatchUpdatePtr = llvm::DomTreeBuilder::SemiNCAInfo<llvm::DominatorTreeBase<mlir::Block, false> >::BatchUpdateInfo*; NodePtr = mlir::Block*]’
  673 |       InsertReachable(DT, BUI, FromTN, ToTN);
      |       ~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
/home/calvinow/git/llvm/llvm/include/llvm/Support/GenericDomTreeConstruction.h:1571:36:   required from ‘void llvm::DomTreeBuilder::InsertEdge(DomTreeT&, typename DomTreeT::NodePtr, typename DomTreeT::NodePtr) [with DomTreeT = llvm::DominatorTreeBase<mlir::Block, false>; typename DomTreeT::NodePtr = mlir::Block*]’
 1571 |   SemiNCAInfo<DomTreeT>::InsertEdge(DT, nullptr, From, To);
      |   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
/home/calvinow/git/llvm/llvm/include/llvm/Support/GenericDomTree.h:657:31:   required from ‘void llvm::DominatorTreeBase<NodeT, IsPostDom>::insertEdge(NodeT*, NodeT*) [with NodeT = mlir::Block; bool IsPostDom = false]’
  657 |     DomTreeBuilder::InsertEdge(*this, From, To);
      |     ~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~
/home/calvinow/git/llvm/mlir/lib/IR/Dominance.cpp:23:22:   required from here
   23 | template class llvm::DominatorTreeBase<Block, /*IsPostDom=*/false>;
      |                      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/calvinow/gnu/include/c++/15.0.0/bits/stl_iterator.h:180:7: error: no matching function for call to ‘llvm::detail::indexed_accessor_range_base<mlir::SuccessorRange, mlir::BlockOperand*, mlir::Block*, mlir::Block*, mlir::Block*>::iterator::iterator()’
  180 |       _GLIBCXX_NOEXCEPT_IF(noexcept(_Iterator()))
      |       ^~~~~~~~~~~~~~~~~~~~
/home/calvinow/git/llvm/llvm/include/llvm/ADT/STLExtras.h:1270:5: note: candidate: ‘llvm::detail::indexed_accessor_range_base<DerivedT, BaseT, T, PointerT, ReferenceT>::iterator::iterator(BaseT, ptrdiff_t) [with DerivedT = mlir::SuccessorRange; BaseT = mlir::BlockOperand*; T = mlir::Block*; PointerT = mlir::Block*; ReferenceT = mlir::Block*; ptrdiff_t = long int]’
 1270 |     iterator(BaseT owner, ptrdiff_t curIndex)
      |     ^~~~~~~~
/home/calvinow/git/llvm/llvm/include/llvm/ADT/STLExtras.h:1270:5: note:   candidate expects 2 arguments, 0 provided
/home/calvinow/git/llvm/llvm/include/llvm/ADT/STLExtras.h:1261:9: note: candidate: ‘constexpr llvm::detail::indexed_accessor_range_base<mlir::SuccessorRange, mlir::BlockOperand*, mlir::Block*, mlir::Block*, mlir::Block*>::iterator::iterator(const llvm::detail::indexed_accessor_range_base<mlir::SuccessorRange, mlir::BlockOperand*, mlir::Block*, mlir::Block*, mlir::Block*>::iterator&)’
 1261 |   class iterator : public indexed_accessor_iterator<iterator, BaseT, T,
      |         ^~~~~~~~
/home/calvinow/git/llvm/llvm/include/llvm/ADT/STLExtras.h:1261:9: note:   candidate expects 1 argument, 0 provided
/home/calvinow/git/llvm/llvm/include/llvm/ADT/STLExtras.h:1261:9: note: candidate: ‘constexpr llvm::detail::indexed_accessor_range_base<mlir::SuccessorRange, mlir::BlockOperand*, mlir::Block*, mlir::Block*, mlir::Block*>::iterator::iterator(llvm::detail::indexed_accessor_range_base<mlir::SuccessorRange, mlir::BlockOperand*, mlir::Block*, mlir::Block*, mlir::Block*>::iterator&&)’
/home/calvinow/git/llvm/llvm/include/llvm/ADT/STLExtras.h:1261:9: note:   candidate expects 1 argument, 0 provided

================================================================================
Second LLVM build error (current gcc-15 release branch):
================================================================================

FAILED: tools/clang/lib/Driver/CMakeFiles/obj.clangDriver.dir/ToolChains/Arch/X86.cpp.o 
/home/calvinow/gnu/bin/g++ -DCLANG_EXPORTS -DGTEST_HAS_RTTI=0 -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -I/home/calvinow/git/llvm/build/tools/clang/lib/Driver -I/home/calvinow/git/llvm/clang/lib/Driver -I/home/calvinow/git/llvm/clang/include -I/home/calvinow/git/llvm/build/tools/clang/include -I/home/calvinow/git/llvm/build/include -I/home/calvinow/git/llvm/llvm/include -Os -pipe -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -Werror=date-time -fno-lifetime-dse -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wno-missing-field-initializers -pedantic -Wno-long-long -Wimplicit-fallthrough -Wno-maybe-uninitialized -Wno-nonnull -Wno-class-memaccess -Wno-redundant-move -Wno-pessimizing-move -Wno-noexcept-type -Wdelete-non-virtual-dtor -Wsuggest-override -Wno-comment -Wno-misleading-indentation -Wctad-maybe-unsupported -fdiagnostics-color -ffunction-sections -fdata-sections -fno-common -Woverloaded-virtual -fno-strict-aliasing -O3 -DNDEBUG -std=c++20  -fno-exceptions -funwind-tables -fno-rtti -MD -MT tools/clang/lib/Driver/CMakeFiles/obj.clangDriver.dir/ToolChains/Arch/X86.cpp.o -MF tools/clang/lib/Driver/CMakeFiles/obj.clangDriver.dir/ToolChains/Arch/X86.cpp.o.d -o tools/clang/lib/Driver/CMakeFiles/obj.clangDriver.dir/ToolChains/Arch/X86.cpp.o -c /home/calvinow/git/llvm/clang/lib/Driver/ToolChains/Arch/X86.cpp
In file included from /home/calvinow/git/llvm/llvm/include/llvm/ADT/STLExtras.h:24,
                 from /home/calvinow/git/llvm/clang/include/clang/Basic/DirectoryEntry.h:21,
                 from /home/calvinow/git/llvm/clang/include/clang/Basic/FileEntry.h:18,
                 from /home/calvinow/git/llvm/clang/include/clang/Basic/SourceLocation.h:17,
                 from /home/calvinow/git/llvm/clang/include/clang/Basic/Diagnostic.h:19,
                 from /home/calvinow/git/llvm/clang/include/clang/Driver/Driver.h:12,
                 from /home/calvinow/git/llvm/clang/lib/Driver/ToolChains/Arch/X86.h:12,
                 from /home/calvinow/git/llvm/clang/lib/Driver/ToolChains/Arch/X86.cpp:9:
/home/calvinow/git/llvm/llvm/include/llvm/ADT/iterator.h: In instantiation of ‘llvm::iterator_adaptor_base<DerivedT, WrappedIteratorT, IteratorCategoryT, T, DifferenceTypeT, PointerT, ReferenceT>::difference_type llvm::iterator_adaptor_base<DerivedT, WrappedIteratorT, IteratorCategoryT, T, DifferenceTypeT, PointerT, ReferenceT>::operator-(const DerivedT&) const [with DerivedT = llvm::StringMapKeyIterator<llvm::StringRef>; WrappedIteratorT = llvm::StringMapConstIterator<llvm::StringRef>; IteratorCategoryT = std::forward_iterator_tag; T = llvm::StringRef; DifferenceTypeT = long int; PointerT = llvm::StringRef*; ReferenceT = llvm::StringRef&; difference_type = long int]’:
/home/calvinow/gnu/include/c++/15.1.1/bits/ranges_base.h:976:23:   required from ‘constexpr std::iter_difference_t<typename std::decay<_Tp>::type> std::ranges::__distance_fn::operator()(_It&&, _Sent) const [with _It = llvm::StringMapKeyIterator<llvm::StringRef>&; _Sent = llvm::StringMapKeyIterator<llvm::StringRef>; std::iter_difference_t<typename std::decay<_Tp>::type> = long int; typename std::decay<_Tp>::type = llvm::StringMapKeyIterator<llvm::StringRef>]’
  976 |       { return __last - static_cast<const decay_t<_It>&>(__first); }
      |                ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/calvinow/gnu/include/c++/15.1.1/bits/stl_vector.h:745:44:   required from ‘constexpr std::vector<_Tp, _Alloc>::vector(_InputIterator, _InputIterator, const allocator_type&) [with _InputIterator = llvm::StringMapKeyIterator<llvm::StringRef>; <template-parameter-2-2> = void; _Tp = llvm::StringRef; _Alloc = std::allocator<llvm::StringRef>; allocator_type = std::allocator<llvm::StringRef>]’
  745 |                 = static_cast<size_type>(ranges::distance(__first, __last));
      |                                          ~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~
/home/calvinow/git/llvm/clang/lib/Driver/ToolChains/Arch/X86.cpp:59:61:   required from here
   59 |                                         ArchMap.keys().end()};
      |                                                             ^
/home/calvinow/git/llvm/llvm/include/llvm/ADT/iterator.h:272:16: error: static assertion failed: The '-' operator is only defined for random access iterators.
  272 |         BaseT::IsRandomAccess,
      |                ^~~~~~~~~~~~~~
/home/calvinow/git/llvm/llvm/include/llvm/ADT/iterator.h:272:16: note: ‘llvm::iterator_facade_base<llvm::StringMapKeyIterator<llvm::StringRef>, std::forward_iterator_tag, llvm::StringRef, long int, llvm::StringRef*, llvm::StringRef&>::IsRandomAccess’ evaluates to false
/home/calvinow/git/llvm/llvm/include/llvm/ADT/iterator.h:274:14: error: no match for ‘operator-’ (operand types are ‘const llvm::StringMapConstIterator<llvm::StringRef>’ and ‘const llvm::StringMapConstIterator<llvm::StringRef>’)
  274 |     return I - RHS.I;
      |            ~~^~~~~~~
/home/calvinow/git/llvm/llvm/include/llvm/ADT/iterator.h:274:14: note: there are 6 candidates
/home/calvinow/git/llvm/llvm/include/llvm/ADT/iterator.h:145:12: note: candidate 1: ‘DerivedT llvm::iterator_facade_base<DerivedT, IteratorCategoryT, T, DifferenceTypeT, PointerT, ReferenceT>::operator-(DifferenceTypeT) const [with DerivedT = llvm::StringMapConstIterator<llvm::StringRef>; IteratorCategoryT = std::forward_iterator_tag; T = const llvm::StringMapEntry<llvm::StringRef>; DifferenceTypeT = long int; PointerT = const llvm::StringMapEntry<llvm::StringRef>*; ReferenceT = const llvm::StringMapEntry<llvm::StringRef>&]’
  145 |   DerivedT operator-(DifferenceTypeT n) const {
      |            ^~~~~~~~
/home/calvinow/git/llvm/llvm/include/llvm/ADT/iterator.h:145:38: note: no known conversion for argument 1 from ‘const llvm::StringMapConstIterator<llvm::StringRef>’ to ‘long int’
  145 |   DerivedT operator-(DifferenceTypeT n) const {
      |                      ~~~~~~~~~~~~~~~~^
In file included from /home/calvinow/git/llvm/llvm/include/llvm/ADT/APFloat.h:18,
                 from /home/calvinow/git/llvm/clang/include/clang/Driver/ToolChain.h:18,
                 from /home/calvinow/git/llvm/clang/include/clang/Driver/Driver.h:20:
/home/calvinow/git/llvm/llvm/include/llvm/ADT/APInt.h:2157:14: note: candidate 2: ‘llvm::APInt llvm::operator-(APInt)’
 2157 | inline APInt operator-(APInt v) {
      |              ^~~~~~~~
/home/calvinow/git/llvm/llvm/include/llvm/ADT/APInt.h:2157:14: note: candidate expects 1 argument, 2 provided
/home/calvinow/git/llvm/llvm/include/llvm/ADT/APInt.h:2182:14: note: candidate 3: ‘llvm::APInt llvm::operator-(APInt, const APInt&)’
 2182 | inline APInt operator-(APInt a, const APInt &b) {
      |              ^~~~~~~~
/home/calvinow/git/llvm/llvm/include/llvm/ADT/APInt.h:2182:30: note: no known conversion for argument 1 from ‘const llvm::StringMapConstIterator<llvm::StringRef>’ to ‘llvm::APInt’
 2182 | inline APInt operator-(APInt a, const APInt &b) {
      |                        ~~~~~~^
/home/calvinow/git/llvm/llvm/include/llvm/ADT/APInt.h:2187:14: note: candidate 4: ‘llvm::APInt llvm::operator-(const APInt&, APInt&&)’
 2187 | inline APInt operator-(const APInt &a, APInt &&b) {
      |              ^~~~~~~~
/home/calvinow/git/llvm/llvm/include/llvm/ADT/APInt.h:2187:37: note: no known conversion for argument 1 from ‘const llvm::StringMapConstIterator<llvm::StringRef>’ to ‘const llvm::APInt&’
 2187 | inline APInt operator-(const APInt &a, APInt &&b) {
      |                        ~~~~~~~~~~~~~^
/home/calvinow/git/llvm/llvm/include/llvm/ADT/APInt.h:2193:14: note: candidate 5: ‘llvm::APInt llvm::operator-(APInt, uint64_t)’
 2193 | inline APInt operator-(APInt a, uint64_t RHS) {
      |              ^~~~~~~~
/home/calvinow/git/llvm/llvm/include/llvm/ADT/APInt.h:2193:30: note: no known conversion for argument 1 from ‘const llvm::StringMapConstIterator<llvm::StringRef>’ to ‘llvm::APInt’
 2193 | inline APInt operator-(APInt a, uint64_t RHS) {
      |                        ~~~~~~^
/home/calvinow/git/llvm/llvm/include/llvm/ADT/APInt.h:2198:14: note: candidate 6: ‘llvm::APInt llvm::operator-(uint64_t, APInt)’
 2198 | inline APInt operator-(uint64_t LHS, APInt b) {
      |              ^~~~~~~~
/home/calvinow/git/llvm/llvm/include/llvm/ADT/APInt.h:2198:33: note: no known conversion for argument 1 from ‘const llvm::StringMapConstIterator<llvm::StringRef>’ to ‘uint64_t’ {aka ‘long unsigned int’}
 2198 | inline APInt operator-(uint64_t LHS, APInt b) {
      |                        ~~~~~~~~~^~~

[jwakely]

It seems that external_symbol_iterator accidentally satisfies sized_sentinel_for<external_symbol_iterator> and libstdc++ starts to use ranges::distance since C++20, where a wrong overload is selected and the ill-formed operator- is called.

That doesn't seem like a libstdc++ bug then.

If the iterator's operator- should not be used to determine the distance, try specializing disable_sized_sentinel_for

The libstdc++ commit that was identified by bisection made std:: uninitialized_copy use an optimized path for contiguous iterators, so if your iterator incorrectly satisfies the concept then it will have problems. That's not a libstdc++ bug though.

[jcalvinowens]

Thanks @jwakely for taking a look. I still filed the "bug" on the bugzilla, just so this will show up in search there for others who might run into it: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120325