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 several times this was committed (e.g. r229831, r233055), it caused several buildbot failures.
Apparently the reason for most failures was both clang and gcc's inability to deal with large numbers (> 10K) of bitset constructor calls in tablegen-generated initializers of instruction info tables. 
This should now be fixed.

llvm-svn: 238192

2 files changed, 3 insertions, 3 deletions

diff --git a/llvm/lib/Target/R600/AsmParser/AMDGPUAsmParser.cpp b/llvm/lib/Target/R600/AsmParser/AMDGPUAsmParser.cpp
index 37ecf0f78fb..19bffd57511 100644
--- a/llvm/lib/Target/R600/AsmParser/AMDGPUAsmParser.cpp
+++ b/llvm/lib/Target/R600/AsmParser/AMDGPUAsmParser.cpp
@@ -321,7 +321,7 @@ public:
       : MCTargetAsmParser(), STI(STI), MII(MII), Parser(_Parser),
         ForcedEncodingSize(0){
 
-    if (!STI.getFeatureBits()) {
+    if (STI.getFeatureBits().none()) {
       // Set default features.
       STI.ToggleFeature("SOUTHERN_ISLANDS");
     }
diff --git a/llvm/lib/Target/R600/MCTargetDesc/R600MCCodeEmitter.cpp b/llvm/lib/Target/R600/MCTargetDesc/R600MCCodeEmitter.cpp
index daa58596614..a809564e3be 100644
--- a/llvm/lib/Target/R600/MCTargetDesc/R600MCCodeEmitter.cpp
+++ b/llvm/lib/Target/R600/MCTargetDesc/R600MCCodeEmitter.cpp
@@ -99,7 +99,7 @@ void R600MCCodeEmitter::encodeInstruction(const MCInst &MI, raw_ostream &OS,
   } else if (IS_VTX(Desc)) {
     uint64_t InstWord01 = getBinaryCodeForInstr(MI, Fixups, STI);
     uint32_t InstWord2 = MI.getOperand(2).getImm(); // Offset
-    if (!(STI.getFeatureBits() & AMDGPU::FeatureCaymanISA)) {
+    if (!(STI.getFeatureBits()[AMDGPU::FeatureCaymanISA])) {
       InstWord2 |= 1 << 19; // Mega-Fetch bit
     }
 
@@ -132,7 +132,7 @@ void R600MCCodeEmitter::encodeInstruction(const MCInst &MI, raw_ostream &OS,
       Emit((uint32_t) 0, OS);
   } else {
     uint64_t Inst = getBinaryCodeForInstr(MI, Fixups, STI);
-    if ((STI.getFeatureBits() & AMDGPU::FeatureR600ALUInst) &&
+    if ((STI.getFeatureBits()[AMDGPU::FeatureR600ALUInst]) &&
        ((Desc.TSFlags & R600_InstFlag::OP1) ||
          Desc.TSFlags & R600_InstFlag::OP2)) {
       uint64_t ISAOpCode = Inst & (0x3FFULL << 39);