[X86][PPC] Support -mlong-double-64

-mlong-double-64 is supported on some ports of gcc (i386, x86_64, and ppc{32,64}).
On many other targets, there will be an error:

    error: unrecognized command line option '-mlong-double-64'

This patch makes the driver option -mlong-double-64 available for x86
and ppc. The CC1 option -mlong-double-64 is available on all targets for
users to test on unsupported targets.

LongDoubleSize is added as a VALUE_LANGOPT so that the option can be
shared with -mlong-double-128 when we support it in clang.

Also, make powerpc*-linux-musl default to use 64-bit long double. It is
currently the only supported ABI on musl and is also how people
configure powerpc*-linux-musl-gcc.

Reviewed By: rnk

Differential Revision: https://reviews.llvm.org/D64067

llvm-svn: 365412

1 files changed, 6 insertions, 0 deletions

diff --git a/clang/lib/Basic/TargetInfo.cpp b/clang/lib/Basic/TargetInfo.cpp
index 5a75b857c21..43ab77289b1 100644
--- a/clang/lib/Basic/TargetInfo.cpp
+++ b/clang/lib/Basic/TargetInfo.cpp
@@ -373,6 +373,12 @@ void TargetInfo::adjust(LangOptions &Opts) {
     LongDoubleFormat = &llvm::APFloat::IEEEquad();
   }
 
+  if (Opts.LongDoubleSize && Opts.LongDoubleSize == DoubleWidth) {
+    LongDoubleWidth = DoubleWidth;
+    LongDoubleAlign = DoubleAlign;
+    LongDoubleFormat = DoubleFormat;
+  }
+
   if (Opts.NewAlignOverride)
     NewAlign = Opts.NewAlignOverride * getCharWidth();