mem: Comment removal and adding constexpr to is_secure bools

This commit removes some comments and adds constexpr in front
of "bool is_secure..." in pif.cc, signature_path.cc, and
signature_path_v2.cc

Change-Id: Icafe1d7c97d1d3fbf6abc12ba87ebb596255b96f

src/mem/cache/prefetch/associative_set.hh

@@ -90,8 +90,6 @@ class AssociativeSet : public AssociativeCache<Entry>
     using AssociativeCache<Entry>::accessEntryByAddr;
     using AssociativeCache<Entry>::findEntry;
     using AssociativeCache<Entry>::insertEntry;
-    // using AssociativeCache<Entry>::getPossibleEntries;
-
     using AssociativeCache<Entry>::replPolicy;
     using AssociativeCache<Entry>::indexingPolicy;
 };

src/mem/cache/prefetch/pif.cc

@@ -176,7 +176,7 @@ PIF::notifyRetiredInst(const Addr pc)
                 // Insert the spatial entry into the history buffer and update
                 // the 'iterator' table to point to the new entry
                 historyBuffer.push_back(spatialCompactor);
-                bool is_secure = false;
+                constexpr bool is_secure = false;
                 auto idx_entry = index.findEntry(spatialCompactor.trigger,
                 is_secure);
                 if (idx_entry != nullptr) {

src/mem/cache/prefetch/signature_path.cc

@@ -192,7 +192,7 @@ SignaturePath::getSignatureEntry(Addr ppn, bool is_secure,
 SignaturePath::PatternEntry &
 SignaturePath::getPatternEntry(Addr signature)
 {
-    bool is_secure = false;
+    constexpr bool is_secure = false;
     PatternEntry* pattern_entry = patternTable.findEntry(signature, is_secure);
     if (pattern_entry != nullptr) {
         // Signature found

src/mem/cache/prefetch/signature_path_v2.cc

@@ -124,8 +124,7 @@ SignaturePathV2::handlePageCrossingLookahead(signature_t signature,
     // of them are unique, there are never "hits" in the GHR
     GlobalHistoryEntry *gh_entry = globalHistoryRegister.findVictim(0);
     assert(gh_entry != nullptr);
-    // Any address value works, as it is never used
-    bool is_secure = false;
+    constexpr bool is_secure = false;
     globalHistoryRegister.insertEntry(0, is_secure, gh_entry); // false,
 
     gh_entry->signature = signature;