Use std::bitset for SubtargetFeatures

Previously, subtarget features were a bitfield with the underlying type being uint64_t. 
Since several targets (X86 and ARM, in particular) have hit or were very close to hitting this bound, switching the features to use a bitset.
No functional change.

The first two times this was committed (r229831, r233055), it caused several buildbot failures. 
At least some of the ARM and MIPS ones were due to gcc/binutils issues, and should now be fixed.

llvm-svn: 237234

1 files changed, 2 insertions, 2 deletions

diff --git a/llvm/lib/Target/ARM/MCTargetDesc/ARMMCCodeEmitter.cpp b/llvm/lib/Target/ARM/MCTargetDesc/ARMMCCodeEmitter.cpp
index 6b650f09f7e..6cbdeba81c7 100644
--- a/llvm/lib/Target/ARM/MCTargetDesc/ARMMCCodeEmitter.cpp
+++ b/llvm/lib/Target/ARM/MCTargetDesc/ARMMCCodeEmitter.cpp
@@ -51,10 +51,10 @@ public:
   ~ARMMCCodeEmitter() override {}
 
   bool isThumb(const MCSubtargetInfo &STI) const {
-    return (STI.getFeatureBits() & ARM::ModeThumb) != 0;
+    return STI.getFeatureBits()[ARM::ModeThumb];
   }
   bool isThumb2(const MCSubtargetInfo &STI) const {
-    return isThumb(STI) && (STI.getFeatureBits() & ARM::FeatureThumb2) != 0;
+    return isThumb(STI) && STI.getFeatureBits()[ARM::FeatureThumb2];
   }
   bool isTargetMachO(const MCSubtargetInfo &STI) const {
     Triple TT(STI.getTargetTriple());