shader: Add utility to resolve identities on a value

src/shader_recompiler/frontend/ir/value.cpp

@@ -79,6 +79,13 @@ IR::Inst* Value::InstRecursive() const {
     return inst;
 }
 
+IR::Value Value::Resolve() const {
+    if (IsIdentity()) {
+        return inst->Arg(0).Resolve();
+    }
+    return *this;
+}
+
 IR::Reg Value::Reg() const {
     ValidateAccess(Type::Reg);
     return reg;

src/shader_recompiler/frontend/ir/value.h

@@ -41,6 +41,7 @@ public:
     [[nodiscard]] IR::Inst* Inst() const;
     [[nodiscard]] IR::Block* Label() const;
     [[nodiscard]] IR::Inst* InstRecursive() const;
+    [[nodiscard]] IR::Value Resolve() const;
     [[nodiscard]] IR::Reg Reg() const;
     [[nodiscard]] IR::Pred Pred() const;
     [[nodiscard]] IR::Attribute Attribute() const;