[flang-commits] [flang] [flang] Warn when F128 is unsupported (PR #102147)

[Daniel Chen via flang-commits]

DanielCChen wrote:

Hi Tom,
On PowerPC, we don't support REAL*16 on AIX, so for the above test case, the new error message from @klausler fix is fine.
However, we support REAL*16 on LoP (Linux on Power). I think we currently using IBM long double format (`ppc_f128`), but I believe eventually we will switch to IEEE 128 format (`f128`). We don't really need to link to the libquadmath library to make it work. 
This PR seems reply on the cmake macro `-DFLANG_RUNTIME_F128_MATH_LIB=libquadmath` being specified, which caused ~100+ runtime test cases to fail when they compiled and ran successfully on LoP.

https://github.com/llvm/llvm-project/pull/102147