runtime: replace LLVM_LIKELY with SWIFT_LIKELY (NFC)

Use the Swift namespaced version of the macro and reduce the dependency
on LLVMSupport.

Author: compnerd

stdlib/public/runtime/Casting.cpp

@@ -2965,7 +2965,7 @@ findBridgeWitness(const Metadata *T) {
   }
 
   auto w = swift_conformsToObjectiveCBridgeable(T);
-  if (LLVM_LIKELY(w))
+  if (SWIFT_LIKELY(w))
     return reinterpret_cast<const _ObjectiveCBridgeableWitnessTable *>(w);
   // Class and ObjC existential metatypes can be bridged, but metatypes can't
   // directly conform to protocols yet. Use a stand-in conformance for a type

stdlib/public/runtime/Metadata.cpp

@@ -4688,8 +4688,9 @@ swift_getAssociatedTypeWitnessSlowImpl(
 #endif
 
   // If the low bit of the witness is clear, it's already a metadata pointer.
-  if (LLVM_LIKELY((uintptr_t(witness) &
-        ProtocolRequirementFlags::AssociatedTypeMangledNameBit) == 0)) {
+  if (SWIFT_LIKELY((reinterpret_cast<uintptr_t>(witness) &
+                    ProtocolRequirementFlags::AssociatedTypeMangledNameBit) ==
+                   0)) {
     // Cached metadata pointers are always complete.
     return MetadataResponse{(const Metadata *)witness, MetadataState::Complete};
   }
@@ -4809,8 +4810,9 @@ swift::swift_getAssociatedTypeWitness(MetadataRequest request,
                                                           extraDiscriminator));
 #endif
 
-  if (LLVM_LIKELY((uintptr_t(witness) &
-        ProtocolRequirementFlags::AssociatedTypeMangledNameBit) == 0)) {
+  if (SWIFT_LIKELY((reinterpret_cast<uintptr_t>(witness) &
+                    ProtocolRequirementFlags::AssociatedTypeMangledNameBit) ==
+                   0)) {
     // Cached metadata pointers are always complete.
     return MetadataResponse{(const Metadata *)witness, MetadataState::Complete};
   }
@@ -4861,8 +4863,9 @@ static const WitnessTable *swift_getAssociatedConformanceWitnessSlowImpl(
 #endif
 
   // Fast path: we've already resolved this to a witness table, so return it.
-  if (LLVM_LIKELY((uintptr_t(witness) &
-         ProtocolRequirementFlags::AssociatedTypeMangledNameBit) == 0)) {
+  if (SWIFT_LIKELY((reinterpret_cast<uintptr_t>(witness) &
+                    ProtocolRequirementFlags::AssociatedTypeMangledNameBit) ==
+                   0)) {
     return static_cast<const WitnessTable *>(witness);
   }
 
@@ -4937,8 +4940,9 @@ const WitnessTable *swift::swift_getAssociatedConformanceWitness(
 #endif
 
   // Fast path: we've already resolved this to a witness table, so return it.
-  if (LLVM_LIKELY((uintptr_t(witness) &
-         ProtocolRequirementFlags::AssociatedTypeMangledNameBit) == 0)) {
+  if (SWIFT_LIKELY((reinterpret_cast<uintptr_t>(witness) &
+                    ProtocolRequirementFlags::AssociatedTypeMangledNameBit) ==
+                   0)) {
     return static_cast<const WitnessTable *>(witness);
   }