cpu: Get rid of the redundant PhysRegIndex type.

It was defined to be effectively the same type as RegIndex, which is a
uint16_t. Having two types for essentially the same thing (which the
compiler would treat as equivalent) adds unnecessary complexity.

Change-Id: Ibf6badc19e3b0a27c3bc3e68def1e686dbef3ea8
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/45228
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Maintainer: Giacomo Travaglini <giacomo.travaglini@arm.com>

src/cpu/o3/dep_graph.hh

@@ -87,27 +87,27 @@ class DependencyGraph
     void reset();
 
     /** Inserts an instruction to be dependent on the given index. */
-    void insert(PhysRegIndex idx, const DynInstPtr &new_inst);
+    void insert(RegIndex idx, const DynInstPtr &new_inst);
 
     /** Sets the producing instruction of a given register. */
-    void setInst(PhysRegIndex idx, const DynInstPtr &new_inst)
+    void setInst(RegIndex idx, const DynInstPtr &new_inst)
     { dependGraph[idx].inst = new_inst; }
 
     /** Clears the producing instruction. */
-    void clearInst(PhysRegIndex idx)
+    void clearInst(RegIndex idx)
     { dependGraph[idx].inst = NULL; }
 
     /** Removes an instruction from a single linked list. */
-    void remove(PhysRegIndex idx, const DynInstPtr &inst_to_remove);
+    void remove(RegIndex idx, const DynInstPtr &inst_to_remove);
 
     /** Removes and returns the newest dependent of a specific register. */
-    DynInstPtr pop(PhysRegIndex idx);
+    DynInstPtr pop(RegIndex idx);
 
     /** Checks if the entire dependency graph is empty. */
     bool empty() const;
 
     /** Checks if there are any dependents on a specific register. */
-    bool empty(PhysRegIndex idx) const { return !dependGraph[idx].next; }
+    bool empty(RegIndex idx) const { return !dependGraph[idx].next; }
 
     /** Debugging function to dump out the dependency graph.
      */
@@ -179,8 +179,7 @@ DependencyGraph<DynInstPtr>::reset()
 
 template <class DynInstPtr>
 void
-DependencyGraph<DynInstPtr>::insert(PhysRegIndex idx,
-        const DynInstPtr &new_inst)
+DependencyGraph<DynInstPtr>::insert(RegIndex idx, const DynInstPtr &new_inst)
 {
     //Add this new, dependent instruction at the head of the dependency
     //chain.
@@ -200,7 +199,7 @@ DependencyGraph<DynInstPtr>::insert(PhysRegIndex idx,
 
 template <class DynInstPtr>
 void
-DependencyGraph<DynInstPtr>::remove(PhysRegIndex idx,
+DependencyGraph<DynInstPtr>::remove(RegIndex idx,
                                     const DynInstPtr &inst_to_remove)
 {
     DepEntry *prev = &dependGraph[idx];
@@ -238,7 +237,7 @@ DependencyGraph<DynInstPtr>::remove(PhysRegIndex idx,
 
 template <class DynInstPtr>
 DynInstPtr
-DependencyGraph<DynInstPtr>::pop(PhysRegIndex idx)
+DependencyGraph<DynInstPtr>::pop(RegIndex idx)
 {
     DepEntry *node;
     node = dependGraph[idx].next;

src/cpu/o3/probe/elastic_trace.hh

@@ -87,7 +87,7 @@ class ElasticTrace : public ProbeListenerObject
   public:
     typedef typename O3CPUImpl::DynInstPtr DynInstPtr;
     typedef typename O3CPUImpl::DynInstConstPtr DynInstConstPtr;
-    typedef typename std::pair<InstSeqNum, PhysRegIndex> SeqNumRegPair;
+    typedef typename std::pair<InstSeqNum, RegIndex> SeqNumRegPair;
 
     /** Trace record types corresponding to instruction node types */
     typedef ProtoMessage::InstDepRecord::RecordType RecordType;
@@ -239,7 +239,7 @@ class ElasticTrace : public ProbeListenerObject
      * After Write dependencies. The key is the renamed physical register and
      * the value is the instruction sequence number of its last producer.
      */
-    std::unordered_map<PhysRegIndex, InstSeqNum> physRegDepMap;
+    std::unordered_map<RegIndex, InstSeqNum> physRegDepMap;
 
     /**
      * @defgroup TraceInfo Struct for a record in the instruction dependency

src/cpu/o3/regfile.cc

@@ -72,8 +72,8 @@ PhysRegFile::PhysRegFile(unsigned _numPhysicalIntRegs,
                    + _numPhysicalCCRegs),
       vecMode(vmode)
 {
-    PhysRegIndex phys_reg;
-    PhysRegIndex flat_reg_idx = 0;
+    RegIndex phys_reg;
+    RegIndex flat_reg_idx = 0;
 
     // The initial batch of registers are the integer ones
     for (phys_reg = 0; phys_reg < numPhysicalIntRegs; phys_reg++) {

src/cpu/o3/rob.hh

@@ -62,7 +62,7 @@ class ROB
     typedef typename Impl::O3CPU O3CPU;
     typedef typename Impl::DynInstPtr DynInstPtr;
 
-    typedef std::pair<RegIndex, PhysRegIndex> UnmapInfo;
+    typedef std::pair<RegIndex, RegIndex> UnmapInfo;
     typedef typename std::list<DynInstPtr>::iterator InstIt;
 
     /** Possible ROB statuses. */

src/cpu/reg_class.hh

@@ -188,12 +188,6 @@ class RegId
     }
 };
 
-/** Physical register index type.
- * Although the Impl might be a better for this, but there are a few classes
- * that need this typedef yet are not templated on the Impl.
- */
-using PhysRegIndex = short int;
-
 /** Physical register ID.
  * Like a register ID but physical. The inheritance is private because the
  * only relationship between this types is functional, and it is done to
@@ -201,7 +195,7 @@ using PhysRegIndex = short int;
 class PhysRegId : private RegId
 {
   private:
-    PhysRegIndex flatIdx;
+    RegIndex flatIdx;
     int numPinnedWritesToComplete;
     bool pinned;
 
@@ -211,15 +205,15 @@ class PhysRegId : private RegId
     {}
 
     /** Scalar PhysRegId constructor. */
-    explicit PhysRegId(RegClass _regClass, PhysRegIndex _regIdx,
-              PhysRegIndex _flatIdx)
+    explicit PhysRegId(RegClass _regClass, RegIndex _regIdx,
+              RegIndex _flatIdx)
         : RegId(_regClass, _regIdx), flatIdx(_flatIdx),
           numPinnedWritesToComplete(0), pinned(false)
     {}
 
     /** Vector PhysRegId constructor (w/ elemIndex). */
-    explicit PhysRegId(RegClass _regClass, PhysRegIndex _regIdx,
-              ElemIndex elem_idx, PhysRegIndex flat_idx)
+    explicit PhysRegId(RegClass _regClass, RegIndex _regIdx,
+              ElemIndex elem_idx, RegIndex flat_idx)
         : RegId(_regClass, _regIdx, elem_idx), flatIdx(flat_idx),
           numPinnedWritesToComplete(0), pinned(false)
     {}
@@ -263,7 +257,7 @@ class PhysRegId : private RegId
     bool isFixedMapping() const { return !isRenameable(); }
 
     /** Flat index accessor */
-    const PhysRegIndex& flatIndex() const { return flatIdx; }
+    const RegIndex& flatIndex() const { return flatIdx; }
 
     static PhysRegId
     elemId(PhysRegId* vid, ElemIndex elem)