[IR] Allow matching pointer to vector with opaque pointers.

[hgreving]

Summary

Allows for skipping the pointer to vector type if opaque pointers
are enabled and the matching pointer is a vector pointer when
matching an intrinsic signature in the verifier.

No test added since lacking a target using intrinsic with pointer to
vector arguments.

[aeubanks]

Could you make the title more specific, mentioning intrinsic overloading and opaque pointers?

Also could you add a FIXME saying that other nested types don't properly work with intrinsic overloading but hopefully it doesn't happen in practice?

[hgreving]

In D122203#3398701, @aeubanks wrote:

Could you make the title more specific, mentioning intrinsic overloading and opaque pointers?

Also could you add a FIXME saying that other nested types don't properly work with intrinsic overloading but hopefully it doesn't happen in practice?

Done. Except it has nothing to do with overloading I think. It's matching an intrinsic signature in the verifier if opaque pointers are enabled, overloaded or not..

[nikic]

LGTM. Just to be clear, when you say "vector pointer" you're talking about a "pointer to vector" rather than a "vector of pointers", right?

[hgreving]

In D122203#3399682, @nikic wrote:

LGTM. Just to be clear, when you say "vector pointer" you're talking about a "pointer to vector" rather than a "vector of pointers", right?

Yes, edited.

llvm/lib/IR/Function.cpp

switch (D.Kind) {
     case IITDescriptor::Pointer: {
       PointerType *PT = dyn_cast<PointerType>(Ty);
       if (!PT || PT->getAddressSpace() != D.Pointer_AddressSpace)
         return true;
       if (!PT->isOpaque())
         return matchIntrinsicType(PT->getNonOpaquePointerElementType(), Infos,
                                   ArgTys, DeferredChecks, IsDeferredCheck);
       // Consume IIT descriptors relating to the pointer element type.
-      while (Infos.front().Kind == IITDescriptor::Pointer)
+      // FIXME: Intrinsic type matching of nested single value types or even
+      // aggregates doesn't work properly with opaque pointers but hopefully
+      // doesn't happen in practice.
+      while (Infos.front().Kind == IITDescriptor::Pointer ||
+             Infos.front().Kind == IITDescriptor::Vector)
         Infos = Infos.slice(1);
       Infos = Infos.slice(1);
       return false;
     }
 
     case IITDescriptor::Struct: {
       StructType *ST = dyn_cast<StructType>(Ty);
       if (!ST || ST->getNumElements() != D.Struct_NumElements)