better opt

src/dynarmic/src/dynarmic/ir/opt_passes.cpp

@@ -511,8 +511,8 @@ static void A64GetSetElimination(IR::Block& block) {
     struct RegisterInfo {
         IR::Value register_value;
         TrackingType tracking_type;
-        bool set_instruction_present = false;
         Iterator last_set_instruction;
+        bool set_instruction_present = false;
     };
     std::array<RegisterInfo, 31> reg_info;
     std::array<RegisterInfo, 32> vec_info;
@@ -524,26 +524,25 @@ static void A64GetSetElimination(IR::Block& block) {
             info.last_set_instruction->Invalidate();
             block.Instructions().erase(info.last_set_instruction);
         }
-
         info.register_value = value;
         info.tracking_type = tracking_type;
         info.set_instruction_present = true;
         info.last_set_instruction = set_inst;
     };
-    const auto do_get = [](RegisterInfo& info, Iterator get_inst, TrackingType tracking_type) {
-        // A sequence like
-        // SetX r1 -> GetW r1, is just reading off the lowest 32-bits of the register
-        auto const is_lower_32 = tracking_type == TrackingType::W
-            && info.tracking_type == TrackingType::X;
+    const auto do_get = [&block](RegisterInfo& info, Iterator get_inst, TrackingType tracking_type) {
         if (!info.register_value.IsEmpty() && info.tracking_type == tracking_type) {
             get_inst->ReplaceUsesWith(info.register_value);
-        } else if (!info.register_value.IsEmpty() && is_lower_32) {
+        } else if (!info.register_value.IsEmpty()
+            && tracking_type == TrackingType::W
+            && info.tracking_type == TrackingType::X) {
+            // A sequence like
+            // SetX r1 -> GetW r1, is just reading off the lowest 32-bits of the register
             if (info.register_value.IsImmediate()) {
-                ReplaceUsesWith(*get_inst, true, u32(info.register_value.GetImmediateAsU64() & 0xffff'ffff));
+                ReplaceUsesWith(*get_inst, true, u32(info.register_value.GetImmediateAsU64()));
             } else {
-                info = {};
-                info.register_value = IR::Value(&*get_inst);
-                info.tracking_type = tracking_type;
+                A64::IREmitter ir{block};
+                ir.SetInsertionPointBefore(&*get_inst);
+                get_inst->ReplaceUsesWith(ir.LeastSignificantWord(IR::U64{info.register_value}));
             }
         } else {
             info = {};
@@ -556,27 +555,27 @@ static void A64GetSetElimination(IR::Block& block) {
         switch (opcode) {
         case IR::Opcode::A64GetW: {
             const size_t index = A64::RegNumber(inst->GetArg(0).GetA64RegRef());
-            do_get(reg_info.at(index), inst, TrackingType::W);
+            do_get(reg_info[index], inst, TrackingType::W);
             break;
         }
         case IR::Opcode::A64GetX: {
             const size_t index = A64::RegNumber(inst->GetArg(0).GetA64RegRef());
-            do_get(reg_info.at(index), inst, TrackingType::X);
+            do_get(reg_info[index], inst, TrackingType::X);
             break;
         }
         case IR::Opcode::A64GetS: {
             const size_t index = A64::VecNumber(inst->GetArg(0).GetA64VecRef());
-            do_get(vec_info.at(index), inst, TrackingType::S);
+            do_get(vec_info[index], inst, TrackingType::S);
             break;
         }
         case IR::Opcode::A64GetD: {
             const size_t index = A64::VecNumber(inst->GetArg(0).GetA64VecRef());
-            do_get(vec_info.at(index), inst, TrackingType::D);
+            do_get(vec_info[index], inst, TrackingType::D);
             break;
         }
         case IR::Opcode::A64GetQ: {
             const size_t index = A64::VecNumber(inst->GetArg(0).GetA64VecRef());
-            do_get(vec_info.at(index), inst, TrackingType::Q);
+            do_get(vec_info[index], inst, TrackingType::Q);
             break;
         }
         case IR::Opcode::A64GetSP: {
@@ -589,27 +588,27 @@ static void A64GetSetElimination(IR::Block& block) {
         }
         case IR::Opcode::A64SetW: {
             const size_t index = A64::RegNumber(inst->GetArg(0).GetA64RegRef());
-            do_set(reg_info.at(index), inst->GetArg(1), inst, TrackingType::W);
+            do_set(reg_info[index], inst->GetArg(1), inst, TrackingType::W);
             break;
         }
         case IR::Opcode::A64SetX: {
             const size_t index = A64::RegNumber(inst->GetArg(0).GetA64RegRef());
-            do_set(reg_info.at(index), inst->GetArg(1), inst, TrackingType::X);
+            do_set(reg_info[index], inst->GetArg(1), inst, TrackingType::X);
             break;
         }
         case IR::Opcode::A64SetS: {
             const size_t index = A64::VecNumber(inst->GetArg(0).GetA64VecRef());
-            do_set(vec_info.at(index), inst->GetArg(1), inst, TrackingType::S);
+            do_set(vec_info[index], inst->GetArg(1), inst, TrackingType::S);
             break;
         }
         case IR::Opcode::A64SetD: {
             const size_t index = A64::VecNumber(inst->GetArg(0).GetA64VecRef());
-            do_set(vec_info.at(index), inst->GetArg(1), inst, TrackingType::D);
+            do_set(vec_info[index], inst->GetArg(1), inst, TrackingType::D);
             break;
         }
         case IR::Opcode::A64SetQ: {
             const size_t index = A64::VecNumber(inst->GetArg(0).GetA64VecRef());
-            do_set(vec_info.at(index), inst->GetArg(1), inst, TrackingType::Q);
+            do_set(vec_info[index], inst->GetArg(1), inst, TrackingType::Q);
             break;
         }
         case IR::Opcode::A64SetSP: {