PPU LLVM: Optimize branch list

rpcs3/Emu/Cell/PPUTranslator.cpp

@@ -13,6 +13,7 @@
 #include "util/v128.hpp"
 #include "util/simd.hpp"
 #include <algorithm>
+#include <unordered_set>
 #include <span>
 
 using namespace llvm;
@@ -371,8 +372,50 @@ void PPUTranslator::CallFunction(u64 target, Value* indirect)
 
 		if (_target >= caddr && _target <= cend)
 		{
-			callee = m_module->getOrInsertFunction(fmt::format("__0x%x", target), type);
-			cast<Function>(callee.getCallee())->setCallingConv(CallingConv::GHC);
+			std::unordered_set<u64> passed_targets{_target};
+
+			u32 target_last = _target;
+
+			// Try to follow unconditional branches as long as there is no infinite loop
+			while (target_last != _target)
+			{
+				const ppu_opcode_t op{*ensure(m_info.get_ptr<u32>(target_last))};
+				const ppu_itype::type itype = g_ppu_itype.decode(op.opcode);
+
+				if (((itype == ppu_itype::BC && (op.bo & 0x14) == 0x14) || itype == ppu_itype::B) && !op.lk)
+				{
+					const u32 new_target = (op.aa ? 0 : target_last) + (itype == ppu_itype::B ? +op.bt24 : +op.bt14);
+
+					if (target_last >= caddr && target_last <= cend)
+					{
+						if (passed_targets.emplace(new_target).second)
+						{
+							// Ok
+							target_last = new_target;
+							continue;
+						}
+
+						// Infinite loop detected
+						target_last = _target;
+					}
+
+					// Odd destination
+				}
+				else if (itype == ppu_itype::BCLR && (op.bo & 0x14) == 0x14 && !op.lk)
+				{
+					// Special case: empty function
+					// In this case the branch can be treated as BCLR because previous CIA does not matter
+					indirect = RegLoad(m_lr);
+				}
+
+				break;
+			}
+
+			if (!indirect)
+			{
+				callee = m_module->getOrInsertFunction(fmt::format("__0x%x", target_last - base), type);
+				cast<Function>(callee.getCallee())->setCallingConv(CallingConv::GHC);
+			}
 		}
 		else
 		{