[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, 7 insertions, 20 deletions

diff --git a/clang/lib/Basic/Targets/PPC.h b/clang/lib/Basic/Targets/PPC.h
index 6c132e3841f..85d898cda24 100644
--- a/clang/lib/Basic/Targets/PPC.h
+++ b/clang/lib/Basic/Targets/PPC.h
@@ -345,17 +345,10 @@ public:
       break;
     }
 
-    switch (getTriple().getOS()) {
-    case llvm::Triple::FreeBSD:
-    case llvm::Triple::NetBSD:
-    case llvm::Triple::OpenBSD:
-    // FIXME: -mlong-double-128 is not yet supported on AIX.
-    case llvm::Triple::AIX:
+    if (Triple.isOSFreeBSD() || Triple.isOSNetBSD() || Triple.isOSOpenBSD() ||
+        Triple.getOS() == llvm::Triple::AIX || Triple.isMusl()) {
       LongDoubleWidth = LongDoubleAlign = 64;
       LongDoubleFormat = &llvm::APFloat::IEEEdouble();
-      break;
-    default:
-      break;
     }
 
     // PPC32 supports atomics up to 4 bytes.
@@ -386,19 +379,13 @@ public:
       ABI = Triple.getEnvironment() == llvm::Triple::ELFv2 ? "elfv2" : "elfv1";
     }
 
-    switch (Triple.getOS()) {
-    case llvm::Triple::FreeBSD:
-      LongDoubleWidth = LongDoubleAlign = 64;
-      LongDoubleFormat = &llvm::APFloat::IEEEdouble();
-      break;
-    case llvm::Triple::AIX:
-      // FIXME: -mlong-double-128 is not yet supported on AIX.
+    if (Triple.getOS() == llvm::Triple::AIX)
+      SuitableAlign = 64;
+
+    if (Triple.isOSFreeBSD() || Triple.getOS() == llvm::Triple::AIX ||
+        Triple.isMusl()) {
       LongDoubleWidth = LongDoubleAlign = 64;
       LongDoubleFormat = &llvm::APFloat::IEEEdouble();
-      SuitableAlign = 64;
-      break;
-    default:
-      break;
     }
 
     // PPC64 supports atomics up to 8 bytes.