Index: include/llvm/MC/MCSubtargetInfo.h
===================================================================
--- include/llvm/MC/MCSubtargetInfo.h
+++ include/llvm/MC/MCSubtargetInfo.h
@@ -73,7 +73,9 @@
 
   /// setFeatureBits - Set the feature bits.
   ///
-  void setFeatureBits(FeatureBitset& FeatureBits_) { FeatureBits = FeatureBits_; }
+  void setFeatureBits(const FeatureBitset &FeatureBits_) {
+    FeatureBits = FeatureBits_;
+  }
 
   /// InitMCProcessorInfo - Set or change the CPU (optionally supplemented with
   /// feature string). Recompute feature bits and scheduling model.
Index: lib/Target/Mips/AsmParser/MipsAsmParser.cpp
===================================================================
--- lib/Target/Mips/AsmParser/MipsAsmParser.cpp
+++ lib/Target/Mips/AsmParser/MipsAsmParser.cpp
@@ -43,7 +43,7 @@
 namespace {
 class MipsAssemblerOptions {
 public:
-  MipsAssemblerOptions(uint64_t Features_) : 
+  MipsAssemblerOptions(const FeatureBitset &Features_) :
     ATReg(1), Reorder(true), Macro(true), Features(Features_) {}
 
   MipsAssemblerOptions(const MipsAssemblerOptions *Opts) {
@@ -70,8 +70,8 @@
   void setMacro() { Macro = true; }
   void setNoMacro() { Macro = false; }
 
-  uint64_t getFeatures() const { return Features; }
-  void setFeatures(uint64_t Features_) { Features = Features_; }
+  const FeatureBitset &getFeatures() const { return Features; }
+  void setFeatures(const FeatureBitset &Features_) { Features = Features_; }
 
   // Set of features that are either architecture features or referenced
   // by them (e.g.: FeatureNaN2008 implied by FeatureMips32r6).
@@ -84,7 +84,7 @@
   unsigned ATReg;
   bool Reorder;
   bool Macro;
-  uint64_t Features;
+  FeatureBitset Features;
 };
 }
 
@@ -327,23 +327,23 @@
     STI.setFeatureBits(FeatureBits);
     setAvailableFeatures(
         ComputeAvailableFeatures(STI.ToggleFeature(ArchFeature)));
-    AssemblerOptions.back()->setFeatures(getAvailableFeatures());
+    AssemblerOptions.back()->setFeatures(STI.getFeatureBits());
   }
 
   void setFeatureBits(uint64_t Feature, StringRef FeatureString) {
     if (!(STI.getFeatureBits()[Feature])) {
       setAvailableFeatures(
           ComputeAvailableFeatures(STI.ToggleFeature(FeatureString)));
+      AssemblerOptions.back()->setFeatures(STI.getFeatureBits());
     }
-    AssemblerOptions.back()->setFeatures(getAvailableFeatures());
   }
 
   void clearFeatureBits(uint64_t Feature, StringRef FeatureString) {
     if (STI.getFeatureBits()[Feature]) {
       setAvailableFeatures(
           ComputeAvailableFeatures(STI.ToggleFeature(FeatureString)));
+      AssemblerOptions.back()->setFeatures(STI.getFeatureBits());
     }
-    AssemblerOptions.back()->setFeatures(getAvailableFeatures());
   }
 
 public:
@@ -369,11 +369,11 @@
     
     // Remember the initial assembler options. The user can not modify these.
     AssemblerOptions.push_back(
-                     make_unique<MipsAssemblerOptions>(getAvailableFeatures()));
+                     make_unique<MipsAssemblerOptions>(STI.getFeatureBits()));
     
     // Create an assembler options environment for the user to modify.
     AssemblerOptions.push_back(
-                     make_unique<MipsAssemblerOptions>(getAvailableFeatures()));
+                     make_unique<MipsAssemblerOptions>(STI.getFeatureBits()));
 
     getTargetStreamer().updateABIInfo(*this);
 
@@ -3603,7 +3603,9 @@
     return reportParseError(Loc, ".set pop with no .set push");
 
   AssemblerOptions.pop_back();
-  setAvailableFeatures(AssemblerOptions.back()->getFeatures());
+  setAvailableFeatures(
+      ComputeAvailableFeatures(AssemblerOptions.back()->getFeatures()));
+  STI.setFeatureBits(AssemblerOptions.back()->getFeatures());
 
   getTargetStreamer().emitDirectiveSetPop();
   return false;
@@ -3673,7 +3675,9 @@
     return reportParseError("unexpected token, expected end of statement");
 
   // Reset assembler options to their initial values.
-  setAvailableFeatures(AssemblerOptions.front()->getFeatures());
+  setAvailableFeatures(
+      ComputeAvailableFeatures(AssemblerOptions.front()->getFeatures()));
+  STI.setFeatureBits(AssemblerOptions.front()->getFeatures());
   AssemblerOptions.back()->setFeatures(AssemblerOptions.front()->getFeatures());
 
   getTargetStreamer().emitDirectiveSetMips0();
Index: test/MC/Mips/set-push-pop-directives-bad.s
===================================================================
--- test/MC/Mips/set-push-pop-directives-bad.s
+++ test/MC/Mips/set-push-pop-directives-bad.s
@@ -12,3 +12,12 @@
 # CHECK: :[[@LINE-1]]:19: error: unexpected token, expected end of statement
         .set pop bar
 # CHECK: :[[@LINE-1]]:18: error: unexpected token, expected end of statement
+
+        .set hardfloat
+        .set push
+        .set softfloat
+        add.s $f2, $f2, $f2
+# CHECK: :[[@LINE-1]]:9: error: instruction requires a CPU feature not currently enabled
+        .set pop
+        add.s $f2, $f2, $f2
+# CHECK-NOT: :[[@LINE-1]]:9: error: instruction requires a CPU feature not currently enabled
Index: test/MC/Mips/set-push-pop-directives.s
===================================================================
--- test/MC/Mips/set-push-pop-directives.s
+++ test/MC/Mips/set-push-pop-directives.s
@@ -51,3 +51,20 @@
 # CHECK:  b        1336
 # CHECK:  nop
 # CHECK:  addvi.b  $w15, $w13, 18
+
+    .set push
+    .set dsp
+    lbux    $7, $10($11)
+    .set pop
+
+    .set push
+    .set dsp
+    lbux    $7, $10($11)
+# CHECK-NOT: :[[@LINE-1]]:5: error: instruction requires a CPU feature not currently enabled
+    .set pop
+
+    .set push
+    .set dsp
+    lbux    $7, $10($11)
+# CHECK-NOT: :[[@LINE-1]]:5: error: instruction requires a CPU feature not currently enabled
+    .set pop