[ItaniumMangle] Mangle long double as __float128 for some Power targets

GCC mangles long double like __float128 in order to support
compatibility with ABI variants which had a different interpretation of
long double.

This fixes PR23791.

llvm-svn: 239421

1 files changed, 6 insertions, 0 deletions

diff --git a/clang/lib/Basic/Targets.cpp b/clang/lib/Basic/Targets.cpp
index c0c69248458..9c559796795 100644
--- a/clang/lib/Basic/Targets.cpp
+++ b/clang/lib/Basic/Targets.cpp
@@ -992,6 +992,12 @@ public:
   bool hasSjLjLowering() const override {
     return true;
   }
+
+  bool useFloat128ManglingForLongDouble() const override {
+    return LongDoubleWidth == 128 &&
+           LongDoubleFormat == &llvm::APFloat::PPCDoubleDouble &&
+           getTriple().isOSBinFormatELF();
+  }
 };
 
 const Builtin::Info PPCTargetInfo::BuiltinInfo[] = {