This was declared in FeatureX86_64 but never defined (we use the *64BitMode predicates for instruction defs - but now we need it for scheduler model defs).
Noticed while preparing to add Unsupported features handling to X86 scheduler models.
def HasAMXINT8 : Predicate<"Subtarget->hasAMXINT8()">;
def HasUINTR : Predicate<"Subtarget->hasUINTR()">;
def HasCRC32 : Predicate<"Subtarget->hasCRC32()">;
+
+def HasX86_64 : Predicate<"Subtarget->hasX86_64()">;
def Not64BitMode : Predicate<"!Subtarget->is64Bit()">,
AssemblerPredicate<(all_of (not Is64Bit)), "Not 64-bit mode">;
def In64BitMode : Predicate<"Subtarget->is64Bit()">,