[PATCH] D40673: Add _Float128 as alias to __float128 to enable compilations on Fedora27/glibc2-26

[Melanie Blower via Phabricator via cfe-commits]

mibintc marked 3 inline comments as done.
mibintc added a comment.

added inline replies to Eli and Hubert



================
Comment at: lib/Frontend/InitPreprocessor.cpp:817
   DefineFloatMacros(Builder, "LDBL", &TI.getLongDoubleFormat(), "L");
+  DefineFloatMacros(Builder, "FLT128", &TI.getFloat128Format(), "Q");
+
----------------
hubert.reinterpretcast wrote:
> GCC //does// define these macros under with C++ mode when it would for the C mode, but with the `F128` suffix (that it then interprets as a user-defined literal suffix). Use of these macros under C++ mode would behave differently between GCC and Clang until `Q` is replaced with `F128`.
> 
> In my experience, GCC on //does not// define these macros on platforms where `__float128` is unsupported. This includes `powerpc64le-linux-gnu` without the `-mfloat128` option.
I added a FIXME comment, and also added a check to see if float 128 is supported. Is this OK now?


Repository:
  rL LLVM

https://reviews.llvm.org/D40673