[llvm] [NFC][LLVM] Refactor IIT_ANY payload for vector/element constraint (PR #203506)

[Nikita Popov via llvm-commits]

================
@@ -238,49 +238,48 @@ def IntrTriviallyScalarizable : IntrinsicProperty;
 // IIT constants and utils
 //===----------------------------------------------------------------------===//
 
-// llvm::Intrinsic::IITDescriptor::AnyKind::AK_%
-def AnyKind {
-  int Any        = 0;
-  int AnyInteger = 1;
-  int AnyFloat   = 2;
-  int AnyVector  = 3;
-  int AnyPointer = 4;
+// llvm::Intrinsic::IITDescriptor::AnyKindVectorConstraint::VC_%
+def AnyKindVectorConstraint {
+  int None   = 0;
+  int Vector = 1;
+  int Scalar = 2;
 }
 
-// Placeholder to encode the overload index of the current type. We encode bit
-// 8 = 1 to indicate that this entry needs to be patched up with the overload
-// index (to prevent conflict with any valid not-to-be-patched IIT enccoding
-// byte, whose value will be <= 255). The AnyKind itself is in the lower bits.
-// Note that this is just a transient representation till its gets processed
-// by `DoPatchOverloadIndex` below, so this is *not* the encoding of the
-// final type signature.
-class OverloadIndexPlaceholder<int AnyKindVal> {
-  int ID = 0x100;
-  int ret = !or(ID, AnyKindVal);
+// llvm::Intrinsic::IITDescriptor::AnyKindElementConstraint::EC_%
+def AnyKindElementConstraint {
+  int None    = 0;
+  int Integer = 1;
+  int Float   = 2;
+  int Pointer = 3;
 }
 
-// This class defines how the overload index and the arg kind are actually
-// packed into a single byte for the final IIT table encoding. Overload index is
-// packed in low 5 bits, argument kind is packed in upper 3 bits. This enables
-// us to use the same packing for llvm_any* types, which use a argument kind
-// and for partially dependent types like `LLVMVectorOfAnyPointersToElt` which
-// do not use the argument kind and expect the overload index in the lower bits.
-class PackOverloadIndex<int OverloadIndex, int AnyKindVal> {
-  assert !lt(OverloadIndex, 32), "Cannot support more than 32 overload types";
-  assert !lt(AnyKindVal, 8), "Cannot support more than 8 argument kinds";
-  int ret = !or(!shl(AnyKindVal, 5), OverloadIndex);
+// Placeholder to encode the overload index of the current type. We encode a
+// value > 255 to indicate that this entry needs to be patched up with the
+// overload index (to prevent conflict with any valid not-to-be-patched IIT
+// enccoding byte, whose value will be <= 255). Note that this is just a
----------------
nikic wrote:

```suggestion
// encoding byte, whose value will be <= 255). Note that this is just a
```

https://github.com/llvm/llvm-project/pull/203506