[PATCH] D55057: [Headers] Make max_align_t match GCC's implementation.

[James Y Knight via Phabricator via cfe-commits]

jyknight added inline comments.


================
Comment at: lib/Headers/__stddef_max_align_t.h:40
       __attribute__((__aligned__(__alignof__(long double))));
+#ifdef __i386__
+  __float128 __clang_max_align_nonce3
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Can you fix clang to consistently define `__SIZEOF_FLOAT128__` in InitPreprocessor alongside the rest of the SIZEOF macros?

And then use that to determine whether to add float128 to the union? This change, as is, will break on any target which is i386 but doesn't define __float128, e.g. i386-unknown-unknown.

The only additional target which will be modified with that (that is: the only other target which has a float128 type, but for which max_align isn't already 16) is systemz-*-linux.

But I think that's actually indicating a pre-existing bug in the SystemZ config -- it's configured for a 16-byte long double, with 8-byte alignment, but the ABI doc seems to call for 16-byte alignment. +Ulrich for comment on that.


Repository:
  rC Clang

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D55057/new/

https://reviews.llvm.org/D55057