[MC] Make SubtargetFeatureKV only store one FeatureBitset and use an 'unsigned' to hold the value.

This class is used for two difference tablegen generated tables. For one of the tables the Value FeatureBitset only has one bit set. For the other usage the Implies field was unused.

This patch changes the Value field to just be an unsigned. For the usage that put a real vector in bitset, we now use the previously unused Implies field and leave the Value field unused instead.

This is good for a 16K reduction in the size of llc on my local build with all targets enabled.

llvm-svn: 354243

1 files changed, 11 insertions, 11 deletions

diff --git a/llvm/lib/MC/SubtargetFeature.cpp b/llvm/lib/MC/SubtargetFeature.cpp
index 793f00d46ed..50f979b9d11 100644
--- a/llvm/lib/MC/SubtargetFeature.cpp
+++ b/llvm/lib/MC/SubtargetFeature.cpp
@@ -127,8 +127,8 @@ void SetImpliedBits(FeatureBitset &Bits, const SubtargetFeatureKV &FeatureEntry,
   for (const SubtargetFeatureKV &FE : FeatureTable) {
     if (FeatureEntry.Value == FE.Value) continue;
 
-    if ((FeatureEntry.Implies & FE.Value).any()) {
-      Bits |= FE.Value;
+    if (FeatureEntry.Implies.test(FE.Value)) {
+      Bits.set(FE.Value);
       SetImpliedBits(Bits, FE, FeatureTable);
     }
   }
@@ -142,8 +142,8 @@ void ClearImpliedBits(FeatureBitset &Bits,
   for (const SubtargetFeatureKV &FE : FeatureTable) {
     if (FeatureEntry.Value == FE.Value) continue;
 
-    if ((FE.Implies & FeatureEntry.Value).any()) {
-      Bits &= ~FE.Value;
+    if (FE.Implies.test(FeatureEntry.Value)) {
+      Bits.reset(FE.Value);
       ClearImpliedBits(Bits, FE, FeatureTable);
     }
   }
@@ -157,12 +157,12 @@ SubtargetFeatures::ToggleFeature(FeatureBitset &Bits, StringRef Feature,
       Find(StripFlag(Feature), FeatureTable);
   // If there is a match
   if (FeatureEntry) {
-    if ((Bits & FeatureEntry->Value) == FeatureEntry->Value) {
-      Bits &= ~FeatureEntry->Value;
+    if (Bits.test(FeatureEntry->Value)) {
+      Bits.reset(FeatureEntry->Value);
       // For each feature that implies this, clear it.
       ClearImpliedBits(Bits, *FeatureEntry, FeatureTable);
     } else {
-      Bits |=  FeatureEntry->Value;
+      Bits.set(FeatureEntry->Value);
 
       // For each feature that this implies, set it.
       SetImpliedBits(Bits, *FeatureEntry, FeatureTable);
@@ -184,12 +184,12 @@ void SubtargetFeatures::ApplyFeatureFlag(FeatureBitset &Bits, StringRef Feature,
   if (FeatureEntry) {
     // Enable/disable feature in bits
     if (isEnabled(Feature)) {
-      Bits |= FeatureEntry->Value;
+      Bits.set(FeatureEntry->Value);
 
       // For each feature that this implies, set it.
       SetImpliedBits(Bits, *FeatureEntry, FeatureTable);
     } else {
-      Bits &= ~FeatureEntry->Value;
+      Bits.reset(FeatureEntry->Value);
 
       // For each feature that implies this, clear it.
       ClearImpliedBits(Bits, *FeatureEntry, FeatureTable);
@@ -225,11 +225,11 @@ SubtargetFeatures::getFeatureBits(StringRef CPU,
     // If there is a match
     if (CPUEntry) {
       // Set base feature bits
-      Bits = CPUEntry->Value;
+      Bits = CPUEntry->Implies;
 
       // Set the feature implied by this CPU feature, if any.
       for (auto &FE : FeatureTable) {
-        if ((CPUEntry->Value & FE.Value).any())
+        if (CPUEntry->Implies.test(FE.Value))
           SetImpliedBits(Bits, FE, FeatureTable);
       }
     } else {