[OpenMP] Simplify getFloatTypeSemantics

[MaskRay]

Summary

When the float point representations are the same on the host and on the target device,
(&Target->getLongDoubleFormat() == &AuxTarget->getLongDoubleFormat()),
we can just use AuxTarget->getLongDoubleFormat().

[jdoerfert]

Could we generally require some message for all reviews and commits?

[ABataev]

LG, but I agree, some general description would be good

[MaskRay]

Update description

cfe/trunk/lib/AST/ASTContext.cpp

const llvm::fltSemantics &ASTContext::getFloatTypeSemantics(QualType T) const {
   switch (BT->getKind()) {
   default: llvm_unreachable("Not a floating point type!");
   case BuiltinType::Float16:
   case BuiltinType::Half:
     return Target->getHalfFormat();
   case BuiltinType::Float:      return Target->getFloatFormat();
   case BuiltinType::Double:     return Target->getDoubleFormat();
   case BuiltinType::LongDouble:
-    if (getLangOpts().OpenMP && getLangOpts().OpenMPIsDevice &&
-        &Target->getLongDoubleFormat() != &AuxTarget->getLongDoubleFormat())
+    if (getLangOpts().OpenMP && getLangOpts().OpenMPIsDevice)
       return AuxTarget->getLongDoubleFormat();
     return Target->getLongDoubleFormat();
   case BuiltinType::Float128:
-    if (getLangOpts().OpenMP && getLangOpts().OpenMPIsDevice &&
-        &Target->getFloat128Format() != &AuxTarget->getFloat128Format())
+    if (getLangOpts().OpenMP && getLangOpts().OpenMPIsDevice)
       return AuxTarget->getFloat128Format();
     return Target->getFloat128Format();
   }
 }
 
 CharUnits ASTContext::getDeclAlign(const Decl *D, bool ForAlignof) const {
   unsigned Align = Target->getCharWidth();