[SPIRV] Improve type inference of operand presented by opaque pointers and aggregate types (#98035)

This PR improves type inference of operand presented by opaque pointers
and aggregate types:
* tries to restore original function return type for aggregate types so
that it's possible to deduce a correct type during emit-intrinsics step
(see llvm/test/CodeGen/SPIRV/SpecConstants/restore-spec-type.ll for the
reproducer of the previously existed issue when spirv-val found a
mismatch between object and ptr types in OpStore due to the incorrect
aggregate types tracing),
* explores untyped pointer operands of store to deduce correct pointee
types,
* creates an extension type to track pointee types from emit-intrinsics
step and further instead of direct and naive usage of TypePointerType
that led previously to crashes due to ban of creation of Value of
TypePointerType type,
* tracks instructions with uncomplete type information and tries to
improve their type info after pass calculated types for all machine
functions (it doesn't traverse a code but rather checks only those
instructions which were tracked as uncompleted),
* address more cases of removing unnecessary bitcasts (see, for example,
changes in test/CodeGen/SPIRV/transcoding/OpGenericCastToPtr.ll where
`CHECK-SPIRV-NEXT` in LIT checks show absence of unneeded bitcasts and
unmangled/mangled versions have proper typing now with equivalent type
info),
* address more cases of well known types or relations between types
within instructions (see, for example, atomic*.ll test cases and
Event-related test cases for improved SPIR-V code generated by the
Backend),
* fix the issue of removing unneeded ptrcast instructions in
pre-legalizer pass that led to creation of new assign-type instructions
with the same argument as source in ptrcast and caused errors in type
inference (the reproducer `complex.ll` test case is added to the PR).

Author: VyacheslavLevytskyy

llvm/lib/Target/SPIRV/SPIRVBuiltins.cpp

@@ -169,21 +169,9 @@ using namespace InstructionSet;
 // TableGen records
 //===----------------------------------------------------------------------===//
 
-/// Looks up the demangled builtin call in the SPIRVBuiltins.td records using
-/// the provided \p DemangledCall and specified \p Set.
-///
-/// The lookup follows the following algorithm, returning the first successful
-/// match:
-/// 1. Search with the plain demangled name (expecting a 1:1 match).
-/// 2. Search with the prefix before or suffix after the demangled name
-/// signyfying the type of the first argument.
-///
-/// \returns Wrapper around the demangled call and found builtin definition.
-static std::unique_ptr<const SPIRV::IncomingCall>
-lookupBuiltin(StringRef DemangledCall,
-              SPIRV::InstructionSet::InstructionSet Set,
-              Register ReturnRegister, const SPIRVType *ReturnType,
-              const SmallVectorImpl<Register> &Arguments) {
+namespace SPIRV {
+/// Parses the name part of the demangled builtin call.
+std::string lookupBuiltinNameHelper(StringRef DemangledCall) {
   const static std::string PassPrefix = "(anonymous namespace)::";
   std::string BuiltinName;
   // Itanium Demangler result may have "(anonymous namespace)::" prefix
@@ -215,6 +203,27 @@ lookupBuiltin(StringRef DemangledCall,
     BuiltinName = BuiltinName.substr(0, BuiltinName.find("_R"));
   }
 
+  return BuiltinName;
+}
+} // namespace SPIRV
+
+/// Looks up the demangled builtin call in the SPIRVBuiltins.td records using
+/// the provided \p DemangledCall and specified \p Set.
+///
+/// The lookup follows the following algorithm, returning the first successful
+/// match:
+/// 1. Search with the plain demangled name (expecting a 1:1 match).
+/// 2. Search with the prefix before or suffix after the demangled name
+/// signyfying the type of the first argument.
+///
+/// \returns Wrapper around the demangled call and found builtin definition.
+static std::unique_ptr<const SPIRV::IncomingCall>
+lookupBuiltin(StringRef DemangledCall,
+              SPIRV::InstructionSet::InstructionSet Set,
+              Register ReturnRegister, const SPIRVType *ReturnType,
+              const SmallVectorImpl<Register> &Arguments) {
+  std::string BuiltinName = SPIRV::lookupBuiltinNameHelper(DemangledCall);
+
   SmallVector<StringRef, 10> BuiltinArgumentTypes;
   StringRef BuiltinArgs =
       DemangledCall.slice(DemangledCall.find('(') + 1, DemangledCall.find(')'));
@@ -2610,9 +2619,6 @@ Type *parseBuiltinCallArgumentBaseType(const StringRef DemangledCall,
     // Unable to recognize SPIRV type name.
     return nullptr;
 
-  if (BaseType->isVoidTy())
-    BaseType = Type::getInt8Ty(Ctx);
-
   // Handle "typeN*" or "type vector[N]*".
   TypeStr.consume_back("*");
 
@@ -2621,7 +2627,8 @@ Type *parseBuiltinCallArgumentBaseType(const StringRef DemangledCall,
 
   TypeStr.getAsInteger(10, VecElts);
   if (VecElts > 0)
-    BaseType = VectorType::get(BaseType, VecElts, false);
+    BaseType = VectorType::get(
+        BaseType->isVoidTy() ? Type::getInt8Ty(Ctx) : BaseType, VecElts, false);
 
   return BaseType;
 }

llvm/lib/Target/SPIRV/SPIRVBuiltins.h

@@ -19,6 +19,8 @@
 
 namespace llvm {
 namespace SPIRV {
+/// Parses the name part of the demangled builtin call.
+std::string lookupBuiltinNameHelper(StringRef DemangledCall);
 /// Lowers a builtin function call using the provided \p DemangledCall skeleton
 /// and external instruction \p Set.
 ///