Index: llvm/lib/Target/X86/X86.td
===================================================================
--- llvm/lib/Target/X86/X86.td
+++ llvm/lib/Target/X86/X86.td
@@ -449,6 +449,9 @@
                                         "Merge branches to a three-way "
                                         "conditional branch">;
 
+def FeatureHasDSB : SubtargetFeature<"dsb", "HasDSB", "true",
+                                    "Target has decoded stream buffer">;
+
 // Bonnell
 def ProcIntelAtom : SubtargetFeature<"", "X86ProcFamily", "IntelAtom", "">;
 // Silvermont
@@ -528,6 +531,7 @@
                                                   FeatureXSAVE,
                                                   FeatureXSAVEOPT,
                                                   FeatureSlow3OpsLEA,
+                                                  FeatureHasDSB,
                                                   FeatureFastScalarFSQRT,
                                                   FeatureFastSHLDRotate,
                                                   FeatureMergeToThreeWayBranch];
Index: llvm/lib/Target/X86/X86Subtarget.h
===================================================================
--- llvm/lib/Target/X86/X86Subtarget.h
+++ llvm/lib/Target/X86/X86Subtarget.h
@@ -442,6 +442,9 @@
   /// Threeway branch is profitable in this subtarget.
   bool ThreewayBranchProfitable = false;
 
+  /// Processor supports Decoded Stream Buffer.
+  bool HasDSB = false;
+
   /// What processor and OS we're targeting.
   Triple TargetTriple;
 
@@ -694,6 +697,7 @@
   bool hasPCONFIG() const { return HasPCONFIG; }
   bool hasSGX() const { return HasSGX; }
   bool threewayBranchProfitable() const { return ThreewayBranchProfitable; }
+  bool hasDSB() const { return HasDSB; }
   bool hasINVPCID() const { return HasINVPCID; }
   bool hasENQCMD() const { return HasENQCMD; }
   bool useRetpolineIndirectCalls() const { return UseRetpolineIndirectCalls; }
Index: llvm/lib/Target/X86/X86TargetTransformInfo.h
===================================================================
--- llvm/lib/Target/X86/X86TargetTransformInfo.h
+++ llvm/lib/Target/X86/X86TargetTransformInfo.h
@@ -64,6 +64,7 @@
       X86::FeatureBranchFusion,
       X86::FeatureMacroFusion,
       X86::FeatureMergeToThreeWayBranch,
+      X86::FeatureHasDSB,
       X86::FeaturePadShortFunctions,
       X86::FeaturePOPCNTFalseDeps,
       X86::FeatureSSEUnalignedMem,