Extended Description

in a VS 2019 x86 Native Tools Command Prompt

with llvmorg-12.0.0-rc1 checked out

cmake -GNinja -DCMAKE_BUILD_TYPE=Release -DLLVM_ENABLE_ASSERTIONS=ON -DLLVM_ENABLE_PROJECTS="clang;openmp" ..\llvm
ninja omp

C:\src\llvm.monorepo\openmp\runtime\src\kmp_settings.cpp(3358): error C2131: expression did not evaluate to a constant
C:\src\llvm.monorepo\openmp\runtime\src\kmp_settings.cpp(3358): note: failure was caused by a read of a variable outside its lifetime
C:\src\llvm.monorepo\openmp\runtime\src\kmp_settings.cpp(3358): note: see usage of 'ntraits'

Bisection points to

commit 927af4b
Author: Nawrin Sultana nawrin.sultana@intel.com
Date: Mon Nov 2 16:17:37 2020 -0600

[OpenMP] Modify OMP_ALLOCATOR environment variable

This patch sets the def-allocator-var ICV based on the environment variables
provided in OMP_ALLOCATOR. Previously, only allowed value for OMP_ALLOCATOR
was a predefined memory allocator. OpenMP 5.1 specification allows predefined
memory allocator, predefined mem space, or predefined mem space with traits in
OMP_ALLOCATOR. If an allocator can not be created using the provided environment
variables, the def-allocator-var is set to omp_default_mem_alloc.

Differential Revision: https://reviews.llvm.org/D94985

openmp/runtime/src/kmp_settings.cpp | 391 ++++++++++++++++++++++++------
openmp/runtime/test/env/omp51_alloc_env.c | 31 +++
2 files changed, 353 insertions(+), 69 deletions(-)
create mode 100644 openmp/runtime/test/env/omp51_alloc_env.c

As of this morning the same error happens on the main branch too.