| Issue |
109012
|
| Summary |
SPEC CPU 2017 511.povray_r fails at runtime when built with clang-cl on Windows
|
| Labels |
new issue
|
| Assignees |
|
| Reporter |
pulidocr
|
Hi,
I'm trying to run SPEC CPU 2017 C/C++ benchmarks on Windows with clang-cl, but for some reason it is failing at runtime for 511.povray_r. It fails with `-clang:-O3 -clang:-ffast-math` which suggests it might be a miscompilation. Any help reducing the problem further would be appreciated - for now, I have provided a small config file.
Additional details:
- It used to work with LLVM 17 but fails with LLVM 18.
- Happens on both x64 and ARM64 Windows.
Minimal config file:
```
CC_VERSION_OPTION = ""
CXX_VERSION_OPTION = ""
CC = clang-cl.exe /TC
CLD = clang-cl.exe
CXX = clang-cl.exe /TP
CXXLD = clang-cl.exe
OBJ = .obj
PORTABILITY = /DSPEC_P64
OPTIMIZE = -clang:-O3 -clang:-ffast-math
CXXOPTIMIZE = /EHsc
```
Repro steps:
1. Obtain SPEC CPU 2017 and set it up for Windows
2. Download Visual Studio 2022 and install the "Desktop development with C++" workload.
3. Install clang/LLVM through LLVM's installer.
4. Copy and paste the above config file contents to `spec2017\config\test.cfg`
5. Open x64 Native Tools Command Prompt for VS2022
6. If clang-cl.exe is not already on PATH, `set "PATH=path\to\LLVM\bin;%PATH%`
7. `cd path\to\spec2017`
8. `shrc.bat`
9. `runcpu -a validate --rebuild --size test --iterations 1 -c test 511.povray_r`
10. Observe that the benchmark builds successfully, but fails at runtime with LLVM 18. Works with LLVM 17.
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