[SPIRV] Add support for cl_khr_extended_bit_ops (llvm#120571)

This PR adds support for `cl_khr_extended_bit_ops` in SPIRV Backend.
Note that `cl_khr_extended_bit_ops` only supports types in
```
char, charn, uchar, ucharn, short, shortn, ushort, ushortn, int, intn, uint, uintn, long, longn, ulong, and ulongn
```
where `n is 2, 3, 4, 8, or 16`.

Subsequent PRs will introduce support for non-standard bit width
required by `SPV_KHR_bit_instructions`.

Author: maarquitos14

llvm/lib/Target/SPIRV/SPIRVBuiltins.cpp

@@ -1009,6 +1009,38 @@ static bool buildBarrierInst(const SPIRV::IncomingCall *Call, unsigned Opcode,
   return true;
 }
 
+/// Helper function for building extended bit operations.
+static bool buildExtendedBitOpsInst(const SPIRV::IncomingCall *Call,
+                                    unsigned Opcode,
+                                    MachineIRBuilder &MIRBuilder,
+                                    SPIRVGlobalRegistry *GR) {
+  const SPIRV::DemangledBuiltin *Builtin = Call->Builtin;
+  const auto *ST =
+      static_cast<const SPIRVSubtarget *>(&MIRBuilder.getMF().getSubtarget());
+  if ((Opcode == SPIRV::OpBitFieldInsert ||
+       Opcode == SPIRV::OpBitFieldSExtract ||
+       Opcode == SPIRV::OpBitFieldUExtract || Opcode == SPIRV::OpBitReverse) &&
+      !ST->canUseExtension(SPIRV::Extension::SPV_KHR_bit_instructions)) {
+    std::string DiagMsg = std::string(Builtin->Name) +
+                          ": the builtin requires the following SPIR-V "
+                          "extension: SPV_KHR_bit_instructions";
+    report_fatal_error(DiagMsg.c_str(), false);
+  }
+
+  // Generate SPIRV instruction accordingly.
+  if (Call->isSpirvOp())
+    return buildOpFromWrapper(MIRBuilder, Opcode, Call,
+                              GR->getSPIRVTypeID(Call->ReturnType));
+
+  auto MIB = MIRBuilder.buildInstr(Opcode)
+                 .addDef(Call->ReturnRegister)
+                 .addUse(GR->getSPIRVTypeID(Call->ReturnType));
+  for (unsigned i = 0; i < Call->Arguments.size(); ++i)
+    MIB.addUse(Call->Arguments[i]);
+
+  return true;
+}
+
 static unsigned getNumComponentsForDim(SPIRV::Dim::Dim dim) {
   switch (dim) {
   case SPIRV::Dim::DIM_1D:
@@ -2180,6 +2212,17 @@ static bool generateSpecConstantInst(const SPIRV::IncomingCall *Call,
   }
 }
 
+static bool generateExtendedBitOpsInst(const SPIRV::IncomingCall *Call,
+                                       MachineIRBuilder &MIRBuilder,
+                                       SPIRVGlobalRegistry *GR) {
+  // Lookup the instruction opcode in the TableGen records.
+  const SPIRV::DemangledBuiltin *Builtin = Call->Builtin;
+  unsigned Opcode =
+      SPIRV::lookupNativeBuiltin(Builtin->Name, Builtin->Set)->Opcode;
+
+  return buildExtendedBitOpsInst(Call, Opcode, MIRBuilder, GR);
+}
+
 static bool buildNDRange(const SPIRV::IncomingCall *Call,
                          MachineIRBuilder &MIRBuilder,
                          SPIRVGlobalRegistry *GR) {
@@ -2755,6 +2798,8 @@ std::optional<bool> lowerBuiltin(const StringRef DemangledCall,
     return generateKernelClockInst(Call.get(), MIRBuilder, GR);
   case SPIRV::CoopMatr:
     return generateCoopMatrInst(Call.get(), MIRBuilder, GR);
+  case SPIRV::ExtendedBitOps:
+    return generateExtendedBitOpsInst(Call.get(), MIRBuilder, GR);
   }
   return false;
 }

llvm/lib/Target/SPIRV/SPIRVBuiltins.td

@@ -65,6 +65,7 @@ def CastToPtr : BuiltinGroup;
 def Construct : BuiltinGroup;
 def CoopMatr : BuiltinGroup;
 def ICarryBorrow : BuiltinGroup;
+def ExtendedBitOps : BuiltinGroup;
 
 //===----------------------------------------------------------------------===//
 // Class defining a demangled builtin record. The information in the record
@@ -1465,6 +1466,16 @@ defm : DemangledNativeBuiltin<"__spirv_SatConvertSToU", OpenCL_std, Convert, 1,
 defm : DemangledNativeBuiltin<"__spirv_SatConvertUToS", OpenCL_std, Convert, 1, 1, OpSatConvertUToS>;
 defm : DemangledNativeBuiltin<"__spirv_ConvertUToPtr", OpenCL_std, Convert, 1, 1, OpConvertUToPtr>;
 
+// cl_khr_extended_bit_ops / SPV_KHR_bit_instructions
+defm : DemangledNativeBuiltin<"bitfield_insert", OpenCL_std, ExtendedBitOps, 4, 4, OpBitFieldInsert>;
+defm : DemangledNativeBuiltin<"__spirv_BitFieldInsert", OpenCL_std, ExtendedBitOps, 4, 4, OpBitFieldInsert>;
+defm : DemangledNativeBuiltin<"bitfield_extract_signed", OpenCL_std, ExtendedBitOps, 3, 3, OpBitFieldSExtract>;
+defm : DemangledNativeBuiltin<"__spirv_BitFieldSExtract", OpenCL_std, ExtendedBitOps, 3, 3, OpBitFieldSExtract>;
+defm : DemangledNativeBuiltin<"bitfield_extract_unsigned", OpenCL_std, ExtendedBitOps, 3, 3, OpBitFieldUExtract>;
+defm : DemangledNativeBuiltin<"__spirv_BitFieldUExtract", OpenCL_std, ExtendedBitOps, 3, 3, OpBitFieldUExtract>;
+defm : DemangledNativeBuiltin<"bit_reverse", OpenCL_std, ExtendedBitOps, 1, 1, OpBitReverse>;
+defm : DemangledNativeBuiltin<"__spirv_BitReverse", OpenCL_std, ExtendedBitOps, 1, 1, OpBitReverse>;
+
 // cl_intel_bfloat16_conversions / SPV_INTEL_bfloat16_conversion
 // Multiclass used to define at the same time both a demangled builtin records
 // and a corresponding convert builtin records.