[dynarmic] reduce use 2 bits for LRU and 4 bits for clog2 of bit size

Signed-off-by: lizzie <lizzie@eden-emu.dev>

src/dynarmic/src/dynarmic/backend/x64/reg_alloc.cpp

@@ -118,7 +118,7 @@ void HostLocInfo::AddValue(IR::Inst* inst) noexcept {
     values.push_back(inst);
     ASSERT(size_t(total_uses) + inst->UseCount() < (std::numeric_limits<uint16_t>::max)());
     total_uses += inst->UseCount();
-    max_bit_width = std::max<uint8_t>(max_bit_width, GetBitWidth(inst->GetType()));
+    max_bit_width = std::max<uint8_t>(max_bit_width, std::countr_zero(GetBitWidth(inst->GetType())));
 }
 
 void HostLocInfo::EmitVerboseDebuggingOutput(BlockOfCode* code, size_t host_loc_index) const noexcept {

src/dynarmic/src/dynarmic/backend/x64/reg_alloc.h

@@ -78,7 +78,7 @@ public:
         return std::find(values.begin(), values.end(), inst) != values.end();
     }
     inline size_t GetMaxBitWidth() const noexcept {
-        return max_bit_width;
+        return 1 << max_bit_width;
     }
     void AddValue(IR::Inst* inst) noexcept;
     void EmitVerboseDebuggingOutput(BlockOfCode* code, size_t host_loc_index) const noexcept;
@@ -94,10 +94,10 @@ private:
     uint16_t is_being_used_count = 0; //8
     uint16_t current_references = 0; //8
     // Value state
-    uint8_t max_bit_width = 0; //Valid values: 1,2,4,8,16,32,128
+    uint8_t max_bit_width : 4 = 0; //Valid values: log2(1,2,4,8,16,32,128) = (0, 1, 2, 3, 4, 5, 6)
+    uint8_t lru_counter : 2 = 0; //1
     bool is_scratch : 1 = false; //1
     bool is_set_last_use : 1 = false; //1
-    uint8_t lru_counter = 0; //1
     friend class RegAlloc;
 };
 static_assert(sizeof(HostLocInfo) == 64);