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

[Michal Paszkowski via llvm-commits]

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@@ -983,6 +983,38 @@ 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, Register(0));
+
+  // Generate the instruction.
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michalpaszkowski wrote:

I think the two comments are a bit redundant -- even though it seems we do have similar comments in other places :)

https://github.com/llvm/llvm-project/pull/120571