Method divergeCode

GPCS4/Graphics/Gcn/ControlFlowGraph/GcnDivergentFlow.cpp:61–231

	}

	void GcnDivergentFlow::divergeCode(GcnToken* token)
	{
		// Split the original instruction list into
		// many small groups, each with same executing
		// strategy. (divergent action)
		// Then bracket them using ifs.

		auto& code           = token->getCode();
		auto& insList        = code.insList;
		auto  zeroScalarInst = makeClearInstruction();

		// erase branch instruction,
		// it's no longer needed.
		const auto& lastInst = insList.back();
		if (isBranchInstruction(lastInst))
		{
			insList.pop_back();
		}

		// record the insert position
		auto insertPtr = token->getIterator();

		// Instruction group
		// instructions in a same group have same divergent action
		struct InstGroup
		{
			uint32_t           pc;
			GcnInstructionList insList;
		};

		InstGroup lastGroup;
		InstGroup lastZsGroup;  // last zero scalar group
		GcnToken* lastIf = nullptr;

		auto insertCodeToken = [&](InstGroup&& group) 
		{
			if (group.insList.empty())
			{
				return;
			}

			GcnTokenCode newCode = {};
			newCode.vertexId     = code.vertexId;
			newCode.pc           = group.pc;
			newCode.insList      = std::move(group.insList);
			auto codeToken       = m_factory.createCode(std::move(newCode));
			insertPtr            = m_tokens->insertAfter(insertPtr, codeToken);
		};

		auto resetPc = [](InstGroup& group, uint32_t pc) 
		{
			if (group.insList.empty())
			{
				group.pc = pc;
			}
		};

		auto openScope = [&]()