From d8aa3edf70f3ae2c745b0f10cf81f85a748f45bd Mon Sep 17 00:00:00 2001
From: Frederick Chow <fred.chow@futurewei.com>
Date: Sun, 31 Jan 2021 23:14:56 -0800
Subject: [PATCH] Remove unnecessary first pass in rename2preg by making use of
 OriginalSt's addressTaken field

---
 src/mapleall/maple_me/include/orig_symbol.h  |  4 ++
 src/mapleall/maple_me/src/alias_class.cpp    |  1 +
 src/mapleall/maple_me/src/me_rename2preg.cpp | 57 ++------------------
 src/mapleall/maple_me/src/me_ssa_lpre.cpp    |  5 +-
 4 files changed, 13 insertions(+), 54 deletions(-)

diff --git a/src/mapleall/maple_me/include/orig_symbol.h b/src/mapleall/maple_me/include/orig_symbol.h
index f6658debd9..47b7ee7e78 100644
--- a/src/mapleall/maple_me/include/orig_symbol.h
+++ b/src/mapleall/maple_me/include/orig_symbol.h
@@ -177,6 +177,10 @@ class OriginalSt {
     return addressTaken;
   }
 
+  void SetAddressTaken(bool addrTaken = true) {
+    addressTaken = addrTaken;
+  }
+
   bool IsEPreLocalRefVar() const {
     return epreLocalRefVar;
   }
diff --git a/src/mapleall/maple_me/src/alias_class.cpp b/src/mapleall/maple_me/src/alias_class.cpp
index eac9625f64..9e80e740d3 100644
--- a/src/mapleall/maple_me/src/alias_class.cpp
+++ b/src/mapleall/maple_me/src/alias_class.cpp
@@ -115,6 +115,7 @@ AliasElem *AliasClass::CreateAliasElemsExpr(BaseNode &expr) {
   switch (expr.GetOpCode()) {
     case OP_addrof: {
       OriginalSt &oSt = *static_cast<AddrofSSANode&>(expr).GetSSAVar()->GetOrigSt();
+      oSt.SetAddressTaken();
       FindOrCreateAliasElem(oSt);
       return &FindOrCreateAliasElemOfAddrofOSt(oSt);
     }
diff --git a/src/mapleall/maple_me/src/me_rename2preg.cpp b/src/mapleall/maple_me/src/me_rename2preg.cpp
index 1ac3d90c50..9311778b9b 100755
--- a/src/mapleall/maple_me/src/me_rename2preg.cpp
+++ b/src/mapleall/maple_me/src/me_rename2preg.cpp
@@ -13,7 +13,6 @@
  * See the Mulan PSL v2 for more details.
  */
 #include "me_rename2preg.h"
-#include <unordered_map>
 #include <utils.h>
 #include "mir_builder.h"
 #include "me_irmap.h"
@@ -190,43 +189,6 @@ class SSARename2Preg {
     return name;
   }
 
-  void CollectRefedOst(MeExpr &meExpr) {
-    MeExprOp op = meExpr.GetMeOp();
-    switch (op) {
-      case kMeOpOp: {
-        OpMeExpr &expr = static_cast<OpMeExpr&>(meExpr);
-        for (uint32 i = 0; i < kOperandNumTernary; ++i) {
-          MeExpr *opnd = expr.GetOpnd(i);
-          if (opnd != nullptr) {
-            CollectRefedOst(*opnd);
-          }
-        }
-        break;
-      }
-      case kMeOpNary: {
-        NaryMeExpr &expr = static_cast<NaryMeExpr&>(meExpr);
-        MapleVector<MeExpr*> &opnds = expr.GetOpnds();
-        for (MapleVector<MeExpr*>::iterator it = opnds.begin(); it != opnds.end(); ++it) {
-          CollectRefedOst(*(*it));
-        }
-        break;
-      }
-      case kMeOpIvar: {
-        IvarMeExpr &expr = static_cast<IvarMeExpr&>(meExpr);
-        CollectRefedOst(*(expr.GetBase()));
-        break;
-      }
-      case kMeOpAddrof: {
-        AddrofMeExpr &expr = static_cast<AddrofMeExpr&>(meExpr);
-        referencedOst[expr.GetOstIdx().GetIdx()] = true;
-        break;
-      }
-      default:
-        break;
-    }
-    return;
-  }
-
   void Run(MeFunction &func, MeFuncResultMgr *pFuncRst) {
     bool emptyFunc = func.empty();
     if (!emptyFunc) {
@@ -235,15 +197,6 @@ class SSARename2Preg {
       const AliasClass &aliasClass = utils::ToRef(GetAnalysisResult<MeFuncPhase_ALIASCLASS>(func, funcRst));
 
       cacheProxy.Init(utils::ToRef(ssaTab), irMap);
-      // first pass: collect var that is referenced
-      for (auto it = func.valid_begin(), eIt = func.valid_end(); it != eIt; ++it) {
-        BB &bb = utils::ToRef(*it);
-        for (MeStmt &stmt : bb.GetMeStmts()) {
-          for (size_t i = 0; i < stmt.NumMeStmtOpnds(); ++i) {
-            CollectRefedOst(*stmt.GetOpnd(i));
-          }
-        }
-      }
 
       for (auto it = func.valid_begin(), eIt = func.valid_end(); it != eIt; ++it) {
         BB &bb = utils::ToRef(*it);
@@ -419,10 +372,6 @@ class SSARename2Preg {
       return nullptr;
     }
 
-    if (referencedOst[ost.GetIndex().GetIdx()]) {
-      return nullptr;
-    }
-
     CHECK_FATAL(ost.IsRealSymbol(), "NYI");
     const MIRSymbol &irSymbol = utils::ToRef(ost.GetMIRSymbol());
     if (irSymbol.GetAttr(ATTR_localrefvar)) {
@@ -443,6 +392,9 @@ class SSARename2Preg {
     if (!irSymbol.IsLocal()) {
       return nullptr;
     }
+    if (ost.IsAddressTaken()) {
+      return nullptr;
+    }
     const AliasElem *aliasElem = GetAliasElem(aliasClass, ost);
     if (aliasElem == nullptr || aliasElem->GetClassSet() != nullptr) {
       return nullptr;
@@ -475,9 +427,8 @@ class SSARename2Preg {
 
   CacheProxy cacheProxy;
   FormalRenaming formal;
-  std::unordered_map<uint32, bool> referencedOst;
 };
-}
+}  // namespace
 
 namespace maple {
 
diff --git a/src/mapleall/maple_me/src/me_ssa_lpre.cpp b/src/mapleall/maple_me/src/me_ssa_lpre.cpp
index 5ed80f3ec0..c6b8e7e186 100755
--- a/src/mapleall/maple_me/src/me_ssa_lpre.cpp
+++ b/src/mapleall/maple_me/src/me_ssa_lpre.cpp
@@ -170,7 +170,10 @@ void MeSSALPre::BuildEntryLHSOcc4Formals() const {
   PreWorkCand *workCand = GetWorkCand();
   auto *varMeExpr = static_cast<VarMeExpr*>(workCand->GetTheMeExpr());
   const OriginalSt *ost = ssaTab->GetSymbolOriginalStFromID(varMeExpr->GetOStIdx());
-  if (!ost->IsFormal()) {
+  if (!ost->IsFormal() || ost->IsAddressTaken()) {
+    return;
+  }
+  if (ost->GetFieldID() != 0) {
     return;
   }
   if (assignedFormals.find(ost->GetIndex()) != assignedFormals.end()) {
-- 
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