[flang] Possible regression: fatal internal error: CHECK(range_.Contains(at))

[BwL1289]

fatal internal error: CHECK(range_.Contains(at)) failed at /tmp/<redacted>/staging/llvm_toolchain/source/llvm-project-82f52d9c42d926e23955b42128abff064825d6c8/flang/lib/Parser/provenance.cpp(474)

This looks to be a regression of #77791.

We are building scipy from commit: 76bf366486b0583dca789823878b80d610eb571b. Same behavior on tagged release 1.14.0.

The platform is Amazon Linux 2023 (Fedora based). Checked on both x86_64 (Intel Sapphire Rapids) and aarch64 (AWS Graviton4, neoverse-v2).

See attached log:
flang_llvm_scipy.txt

Tagging @h-vetinari as you're on the front lines with flang and scipy :)

[llvmbot]

@llvm/issue-subscribers-flang-frontend

Author: Benjamin Leff (BwL1289)

``` fatal internal error: CHECK(range_.Contains(at)) failed at /tmp/<redacted>/staging/llvm_toolchain/source/llvm-project-82f52d9c42d926e23955b42128abff064825d6c8/flang/lib/Parser/provenance.cpp(474) ```

This looks to be a regression of #77791.

We are building scipy from commit: 76bf366486b0583dca789823878b80d610eb571b. Same behavior on tagged release 1.14.0.

The platform is Amazon Linux 2023 (Fedora based). Checked on both x86_64 (Intel Sapphire Rapids) and aarch64 (AWS Graviton4, neoverse-v2).

See attached log:
flang_llvm_scipy.txt

Tagging @h-vetinari as you're on the front lines with flang and scipy :)

[kkwli]

We encounter a similar problem when building on AIX with our downstream clang as the build compiler. However, if I switch to use the upstream clang (18.1.8), the problem goes away. I haven't had much success to pinpoint where the problem is. I suspect the file is miscompiled but I may be wrong.

[BwL1289]

@kkwli flang is broken on llvm 18 (see comment).

This means for us it's not an option to rollback.

[BwL1289]

FWIW, appears that the regression was reintroduced in this commit.

See flang/include/flang/Parser/provenance.h and flang/lib/Parser/provenance.cpp.

[klausler]

@clementval

[klausler]

that commit doesn't have anything to do with the driver, though

[clementval]

Do you have a way to reproduce this?

[BwL1289]

@clementval is that a question for me or @klausler?

Let me know how I can best support.

[clementval]

@clementval is that a question for me or @klausler?

Let me know how I can best support.

For you @BwL1289. Do you have a reproducer or a way to reproduce the build failure if I want to do it locally?

[h-vetinari]

Tagging @h-vetinari as you're on the front lines with flang and scipy :)

Thanks for the ping. I've been building scipy with the flang 19 release candidates, and that works. You seem to be building flang 20 from main? If so, more power to you - the earlier we catch potential regressions, the better!

To that effect, @kiranchandramohan had mentioned on discourse:

Ideally if we can set up a CI that always tests main development branch with scipy on Windows then we can guard against regressions.

I've been working on getting support for (llvm-)flang into meson, but unfortunately mesonbuild/meson#13323 narrowly missed the 1.5 release. It'll be in 1.6 but that'll still take a few month AFAIU. Once meson 1.6 is out, it should be relatively easy to set up the mentioned CI.