[PATCH] D64067: [X86][PPC] Support -mlong-double-64

Thu Jul 18 13:18:23 PDT 2019

rnk added a comment.

In D64067#1592201 <https://reviews.llvm.org/D64067#1592201>, @troyj wrote:

> Hi, we just inherited this commit at Cray when we did our latest upstream merge and there are a few problems with it that I'd like to point out.  Sorry that I was not part of the initial discussion here, but I didn't know that this work was being done and I had already done it for x86 in our downstream compiler a while ago.
>
> 1. This patch adds the -m options to f_Group, which is weird.  They should be in m_Group since they are target-specific.  I actually implemented them as part of a subgroup of m_Group so that I can take the last option from that group that appears on the command line.

Oops, seems like a bug.

> 2. This patch lacks the GNU -mlong-double-80 option for x86.
> 3. Instead of tracking the size in clang/Basic/LangOptions.def, I track it in clang/Basic/TargetOptions.h.  This is a target-specific thing afterall.

Sema needs to know about this option for `sizeof(long double)`. I believe that's the guiding line between the various option kinds. However, it means almost everything ends up being a language option, for better or worse.

> We're trying to resolve merge conflicts with this change and might be able to submit a patch to help reduce our differences.  Would that be of interest?

Sounds good.

Repository:
  rL LLVM

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https://reviews.llvm.org/D64067