[X86] Add FeatureSlowBTMem to Haswell, Broadwell, Skylake, Cannonlake, and Knights Landing CPUs.

[craig.topper]

Summary

I see nothing in Agner Fog's tables to indicate that this improved between Ivy Bridge and Haswell. It's also set for all Atom CPUs so I assume KNL should have it too.

[gadi.haber]

Yes. The X86 Bit Test is known to run slowly on all X86 CPUs.

lib/Target/X86/X86.td

def HSWFeatures : ProcessorFeatures<IVBFeatures.Value, [
   FeatureERMSB,
   FeatureFMA,
   FeatureLZCNT,
   FeatureMOVBE
 ]>;
 
 class HaswellProc<string Name> : ProcModel<Name, HaswellModel,
                                            HSWFeatures.Value, [
-  ProcIntelHSW
+  ProcIntelHSW,
+  FeatureSlowBTMem
 ]>;
 def : HaswellProc<"haswell">;
 def : HaswellProc<"core-avx2">; // Legacy alias.
 
 def BDWFeatures : ProcessorFeatures<HSWFeatures.Value, [
   FeatureADX,
   FeatureRDSEED
 ]>;
 class BroadwellProc<string Name> : ProcModel<Name, HaswellModel,
                                              BDWFeatures.Value, [
-  ProcIntelBDW
+  ProcIntelBDW,
+  FeatureSlowBTMem
 ]>;
 def : BroadwellProc<"broadwell">;
 
 def SKLFeatures : ProcessorFeatures<BDWFeatures.Value, [
   FeatureMPX,
   FeatureRTM,
   FeatureXSAVEC,
   FeatureXSAVES,
   FeatureSGX,
   FeatureCLFLUSHOPT,
   FeatureFastVectorFSQRT
 ]>;
 
 class SkylakeClientProc<string Name> : ProcModel<Name, SkylakeClientModel,
                                                  SKLFeatures.Value, [
-  ProcIntelSKL
+  ProcIntelSKL,
+  FeatureSlowBTMem
 ]>;
 def : SkylakeClientProc<"skylake">;
 
 // FIXME: define KNL model
 class KnightsLandingProc<string Name> : ProcModel<Name, HaswellModel,
                                                   IVBFeatures.Value, [
   ProcIntelKNL,                                                  
+  FeatureSlowBTMem,
   FeatureAVX512,
   FeatureERI,
   FeatureCDI,
   FeaturePFI,
   FeaturePREFETCHWT1,
   FeatureADX,
   FeatureRDSEED,
   FeatureMOVBE,
def SKXFeatures : ProcessorFeatures<SKLFeatures.Value, [
   FeatureBWI,
   FeatureVLX,
   FeaturePKU,
   FeatureCLWB
 ]>;
 
 class SkylakeServerProc<string Name> : ProcModel<Name, SkylakeServerModel,
                                                  SKXFeatures.Value, [
-    ProcIntelSKX
-  ]>;
+  ProcIntelSKX,
+  FeatureSlowBTMem
 def : SkylakeServerProc<"skylake-avx512">;
 def : SkylakeServerProc<"skx">; // Legacy alias.
 
 def CNLFeatures : ProcessorFeatures<SKXFeatures.Value, [
   FeatureVBMI,
   FeatureIFMA,
   FeatureSHA
 ]>;
 
 class CannonlakeProc<string Name> : ProcModel<Name, HaswellModel,
                                               CNLFeatures.Value, [
-  ProcIntelCNL
+  ProcIntelCNL,
+  FeatureSlowBTMem
 ]>;
 def : CannonlakeProc<"cannonlake">;
 
 // AMD CPUs.
 
 def : Proc<"k6",              [FeatureX87, FeatureSlowUAMem16, FeatureMMX]>;
 def : Proc<"k6-2",            [FeatureX87, FeatureSlowUAMem16, Feature3DNow]>;
 def : Proc<"k6-3",            [FeatureX87, FeatureSlowUAMem16, Feature3DNow]>;