[PATCH] D64289: [OpenMP] Fix 128-bit long double support on target

[Alexey Bataev via Phabricator via cfe-commits]

ABataev added inline comments.


================
Comment at: clang/lib/Sema/SemaOpenMP.cpp:1596
         << Ty << E->getSourceRange();
+  if (Ty->isRealFloatingType()) {
+    llvm::APFloatBase::Semantics Sem = llvm::APFloatBase::SemanticsToEnum(
----------------
jdenny wrote:
> ABataev wrote:
> > Why do we need all this stuff? I think the original code works good here, we just need to improve the message.
> > Why do we need all this stuff? I think the original code works good here, we just need to improve the message.
> 
> It seems we've been miscommunicating.  Let's review the discussion so far, point by point, and I'll show you how I arrived at this code.  I think the first major point is as follows.
> 
> I asked:
> > Are you intentionally requiring support for __float128 when the source type is 128-bit long double? That seems to mean powerpc64le cannot offload to itself.
> 
> You replied:
> > No, if the host has 128 bit long double, the device must also have 128 bit long double. It has nothing to do with the float128 type itself.
> 
> I thought you were agreeing with my understanding.  That is, the original code requires `__float128` support even when 128-bit `long double` is in use.  That's why powerpc64le cannot offload to itself.  How does the original code require `__float128`?  It checks `Context.getTargetInfo().hasFloat128Type()`.  As far as I can tell, that checks for `__float128` support, and it does not check for 128-bit `long double` support.  That's why powerpc64le cannot offload to itself.
> 
> I'll review other points later so we can discuss them.  First, let's see if we can agree on this point.
> 
My point about ppc64le is:
If the host code uses long double 128 bit long, tbe device long double also must be 128 bit long. But if device does not support 128bit FP type naturally, user cannot do any operations with it except just load/stores.
Forget about float128 type, we talk about 128bit long double here.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D64289/new/

https://reviews.llvm.org/D64289