a32_get_set_elimination_pass: Reduce NZC to 00C

src/dynarmic/backend/x64/a32_emit_x64.cpp

@@ -555,6 +555,17 @@ void A32EmitX64::EmitA32SetCpsrNZ(A32EmitContext& ctx, IR::Inst* inst) {
 void A32EmitX64::EmitA32SetCpsrNZC(A32EmitContext& ctx, IR::Inst* inst) {
     auto args = ctx.reg_alloc.GetArgumentInfo(inst);
 
+    if (args[0].IsImmediate()) {
+        if (args[1].IsImmediate()) {
+            const bool c = args[1].GetImmediateU1();
+
+            code.mov(code.byte[r15 + offsetof(A32JitState, cpsr_nzcv) + 1], c);
+        } else {
+            const Xbyak::Reg8 c = ctx.reg_alloc.UseGpr(args[1]).cvt8();
+
+            code.mov(code.byte[r15 + offsetof(A32JitState, cpsr_nzcv) + 1], c);
+        }
+    } else {
         ctx.reg_alloc.Use(args[0], HostLoc::RAX);
 
         if (args[1].IsImmediate()) {
@@ -570,6 +581,7 @@ void A32EmitX64::EmitA32SetCpsrNZC(A32EmitContext& ctx, IR::Inst* inst) {
             code.or_(al, c);
             code.mov(code.byte[r15 + offsetof(A32JitState, cpsr_nzcv) + 1], al);
         }
+    }
 }
 
 static void EmitGetFlag(BlockOfCode& code, A32EmitContext& ctx, IR::Inst* inst, size_t flag_bit) {

src/dynarmic/ir/opt/a32_get_set_elimination_pass.cpp

@@ -204,8 +204,12 @@ void A32GetSetElimination(IR::Block& block) {
             break;
         }
         case IR::Opcode::A32SetCpsrNZ: {
+            if (cpsr_info.nzc.set_instruction_present) {
+                cpsr_info.nzc.last_set_instruction->SetArg(0, IR::Value::EmptyNZCVImmediateMarker());
+            }
+
             // cpsr_info.c remains valid
-            cpsr_info.nzc = {};  // TODO: Consider reduction of previous to a SetCFlag operation
+            cpsr_info.nzc = {};
             cpsr_info.nzcv = {};
             do_set(cpsr_info.nz, inst->GetArg(0), inst);
             break;

src/dynarmic/ir/value.cpp

@@ -79,6 +79,12 @@ Value::Value(AccType value)
     inner.imm_acctype = value;
 }
 
+Value Value::EmptyNZCVImmediateMarker() {
+    Value result{};
+    result.type = Type::NZCVFlags;
+    return result;
+}
+
 bool Value::IsIdentity() const {
     if (type == Type::Opaque)
         return inner.inst->GetOpcode() == Opcode::Identity;

src/dynarmic/ir/value.h

@@ -53,6 +53,8 @@ public:
     explicit Value(Cond value);
     explicit Value(AccType value);
 
+    static Value EmptyNZCVImmediateMarker();
+
     bool IsIdentity() const;
     bool IsEmpty() const;
     bool IsImmediate() const;