P4C
The P4 Compiler
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P4::DoSimplifySelectCases Class Reference

#include <simplifySelectCases.h>

Inheritance diagram for P4::DoSimplifySelectCases:
[legend]

Public Member Functions

 DoSimplifySelectCases (const TypeMap *typeMap, bool requireConstants)
 
const IR::Nodepreorder (IR::SelectExpression *expression) override
 
- Public Member Functions inherited from P4::Transform
const IR::Nodeapply_visitor (const IR::Node *, const char *name=0) override
 
profile_t init_apply (const IR::Node *root) override
 
virtual void loop_revisit (const IR::Node *)
 
virtual const IR::Nodepostorder (IR::Node *n)
 
virtual const IR::Nodepreorder (IR::Node *n)
 
void prune ()
 
virtual void revisit (const IR::Node *, const IR::Node *)
 
void revisit_visited ()
 
bool visit_in_progress (const IR::Node *) const
 
void visitAgain () const override
 
void visitOnce () const override
 
- Public Member Functions inherited from P4::Visitor
virtual bool check_global (cstring)
 
virtual void clear_globals ()
 
virtual Visitorclone () const
 
virtual ControlFlowVisitorcontrolFlowVisitor ()
 
virtual void end_apply ()
 
virtual void end_apply (const IR::Node *root)
 
virtual void erase_global (cstring)
 
template<class T >
const T * findContext () const
 
template<class T >
const T * findContext (const Context *&c) const
 
template<class T >
const T * findOrigCtxt () const
 
template<class T >
const T * findOrigCtxt (const Context *&c) const
 
virtual Visitorflow_clone ()
 
virtual void flow_merge (Visitor &)
 
virtual bool flow_merge_closure (Visitor &)
 
virtual void flow_merge_global_from (cstring)
 
virtual void flow_merge_global_to (cstring)
 
const ContextgetChildContext () const
 
int getChildrenVisited () const
 
const ContextgetContext () const
 
int getContextDepth () const
 
const IR::NodegetCurrentNode () const
 
template<class T >
const T * getCurrentNode () const
 
const IR::NodegetOriginal () const
 
template<class T >
const T * getOriginal () const
 
template<class T >
const T * getParent () const
 
virtual bool has_flow_joins () const
 
profile_t init_apply (const IR::Node *root, const Context *parent_context)
 
bool isInContext (const IR::Node *n) const
 
virtual const char * name () const
 
template<class T >
void parallel_visit (const IR::Vector< T > &v, const char *name, int cidx)
 
template<class T >
void parallel_visit (const IR::Vector< T > &v, const char *name=0)
 
template<class T >
void parallel_visit (IR::Vector< T > &v, const char *name, int cidx)
 
template<class T >
void parallel_visit (IR::Vector< T > &v, const char *name=0)
 
void print_context () const
 
const VisitorsetCalledBy (const Visitor *visitor)
 
void setName (const char *name)
 
void visit (const IR::Node &n, const char *name, int cidx)
 
void visit (const IR::Node &n, const char *name=0)
 
void visit (const IR::Node *&n, const char *name, int cidx)
 
void visit (const IR::Node *&n, const char *name=0)
 
void visit (const IR::Node *const &n, const char *name, int cidx)
 
void visit (const IR::Node *const &n, const char *name=0)
 
void visit (IR::Node &n, const char *name, int cidx)
 
void visit (IR::Node &n, const char *name=0)
 
void visit (IR::Node *&, const char *=0, int=0)
 
template<class T , typename = std::enable_if_t<Util::has_SourceInfo_v<T> && !std::is_pointer_v<T>>, class... Args>
void warn (const int kind, const char *format, const T &node, Args &&...args)
 The const ref variant of the above.
 
template<class T , typename = std::enable_if_t<Util::has_SourceInfo_v<T>>, class... Args>
void warn (const int kind, const char *format, const T *node, Args &&...args)
 
bool warning_enabled (int warning_kind) const
 

Additional Inherited Members

- Public Types inherited from P4::Visitor
typedef Visitor_Context Context
 
- Static Public Member Functions inherited from P4::Visitor
static cstring demangle (const char *)
 
static bool warning_enabled (const Visitor *visitor, int warning_kind)
 
- Public Attributes inherited from P4::Visitor
const Visitorcalled_by = nullptr
 
cstring internalName
 
SplitFlowVisit_base *& split_link
 
SplitFlowVisit_basesplit_link_mem = nullptr
 
- Protected Member Functions inherited from P4::Transform
const IR::Nodetransform_child (const IR::Node *child)
 
- Protected Member Functions inherited from P4::Visitor
virtual void init_join_flows (const IR::Node *)
 
virtual bool join_flows (const IR::Node *)
 
virtual void post_join_flows (const IR::Node *, const IR::Node *)
 
void visit_children (const IR::Node *, std::function< void()> fn)
 
- Protected Attributes inherited from P4::Transform
bool forceClone = false
 
- Protected Attributes inherited from P4::Visitor
bool dontForwardChildrenBeforePreorder = false
 
bool joinFlows = false
 
bool visitDagOnce = true
 

Detailed Description

This pass analyzes reachability of select cases.

  • If there is just one case label, the select statement is eliminated.
  • If a case label appears after the default label, the case is unreachable and therefore eliminated.

If requireConstants is true this pass requires that all select labels evaluate to constants.

Precondition
Assumes that there are no side-effects in the evaluation of select labels.
Postcondition
Unreachable case labels are removed. Case statement with a single label is replaced with a direct transition