[libc-commits] [clang] [libc] [clang] Make __builtin_exp and __builtin_expf constexpr. (PR #199808)

[via libc-commits]

lntue wrote:

Hmm, I'm so confused.  For some reason, the CI's keep failing the non-constexpr on overflow tests:
```
FAIL: Clang :: Sema/constant-builtins-exp.cpp (25215 of 25215)
******************** TEST 'Clang :: Sema/constant-builtins-exp.cpp' FAILED ********************
Exit Code: 1
Command Output (stdout):
--
# RUN: at line 1
/home/gha/actions-runner/_work/llvm-project/llvm-project/build/bin/clang -cc1 -internal-isystem /home/gha/actions-runner/_work/llvm-project/llvm-project/build/lib/clang/23/include -nostdsysteminc -std=c++17 -fsyntax-only -verify /home/gha/actions-runner/_work/llvm-project/llvm-project/clang/test/Sema/constant-builtins-exp.cpp
# executed command: /home/gha/actions-runner/_work/llvm-project/llvm-project/build/bin/clang -cc1 -internal-isystem /home/gha/actions-runner/_work/llvm-project/llvm-project/build/lib/clang/23/include -nostdsysteminc -std=c++17 -fsyntax-only -verify /home/gha/actions-runner/_work/llvm-project/llvm-project/clang/test/Sema/constant-builtins-exp.cpp
# .---command stderr------------
# | error: 'expected-error' diagnostics expected but not seen: 
# |   File /home/gha/actions-runner/_work/llvm-project/llvm-project/clang/test/Sema/constant-builtins-exp.cpp Line 15: static assertion expression is not an integral constant expression
# |   File /home/gha/actions-runner/_work/llvm-project/llvm-project/clang/test/Sema/constant-builtins-exp.cpp Line 28: static assertion expression is not an integral constant expression
# | 2 errors generated.
# `-----------------------------
# error: command failed with exit status: 1
--
```
but it passed when I build and run it locally, using the same `cmake` commands in the Linux CI.  And the similar APFloat tests passed.  @hubert-reinterpretcast @jcranmer-intel 

https://github.com/llvm/llvm-project/pull/199808