From 63dfd62bf84b5905725070f8b9a0623165654b5f Mon Sep 17 00:00:00 2001
From: Juergen Ributzka <juergen@apple.com>
Date: Tue, 25 Mar 2014 21:21:10 +0000
Subject: [PATCH] [Constant Hoisting] Make the constant candidate map local to
 the collectConstantCandidates method.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204758 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Transforms/Scalar/ConstantHoisting.cpp | 25 ++++++++++++----------
 1 file changed, 14 insertions(+), 11 deletions(-)

diff --git a/lib/Transforms/Scalar/ConstantHoisting.cpp b/lib/Transforms/Scalar/ConstantHoisting.cpp
index cd0801d1efa..b8c282a4e56 100644
--- a/lib/Transforms/Scalar/ConstantHoisting.cpp
+++ b/lib/Transforms/Scalar/ConstantHoisting.cpp
@@ -109,7 +109,6 @@ class ConstantHoisting : public FunctionPass {
   BasicBlock *Entry;
 
   /// Keeps track of constant candidates found in the function.
-  ConstCandMapType ConstCandMap;
   ConstCandVecType ConstCandVec;
 
   /// Keep track of cast instructions we already cloned.
@@ -146,7 +145,6 @@ private:
     ConstantVec.clear();
     ClonedCastMap.clear();
     ConstCandVec.clear();
-    ConstCandMap.clear();
 
     TTI = nullptr;
     DT = nullptr;
@@ -166,9 +164,11 @@ private:
   BasicBlock *findIDomOfAllUses(const ConstantUseListType &Uses) const;
   Instruction *findMatInsertPt(Instruction *Inst, unsigned Idx = ~0U) const;
   Instruction *findConstantInsertionPoint(const ConstantInfo &ConstInfo) const;
-  void collectConstantCandidates(Instruction *Inst, unsigned Idx,
+  void collectConstantCandidates(ConstCandMapType &ConstCandMap,
+                                 Instruction *Inst, unsigned Idx,
                                  ConstantInt *ConstInt);
-  void collectConstantCandidates(Instruction *Inst);
+  void collectConstantCandidates(ConstCandMapType &ConstCandMap,
+                                 Instruction *Inst);
   void collectConstantCandidates(Function &Fn);
   void findAndMakeBaseConstant(ConstCandVecType::iterator S,
                                ConstCandVecType::iterator E);
@@ -295,7 +295,8 @@ findConstantInsertionPoint(const ConstantInfo &ConstInfo) const {
 /// The operand at index Idx is not necessarily the constant integer itself. It
 /// could also be a cast instruction or a constant expression that uses the
 // constant integer.
-void ConstantHoisting::collectConstantCandidates(Instruction *Inst,
+void ConstantHoisting::collectConstantCandidates(ConstCandMapType &ConstCandMap,
+                                                 Instruction *Inst,
                                                  unsigned Idx,
                                                  ConstantInt *ConstInt) {
   unsigned Cost;
@@ -331,7 +332,8 @@ void ConstantHoisting::collectConstantCandidates(Instruction *Inst,
 
 /// \brief Scan the instruction for expensive integer constants and record them
 /// in the constant candidate vector.
-void ConstantHoisting::collectConstantCandidates(Instruction *Inst) {
+void ConstantHoisting::collectConstantCandidates(ConstCandMapType &ConstCandMap,
+                                                 Instruction *Inst) {
   // Skip all cast instructions. They are visited indirectly later on.
   if (Inst->isCast())
     return;
@@ -345,9 +347,9 @@ void ConstantHoisting::collectConstantCandidates(Instruction *Inst) {
   for (unsigned Idx = 0, E = Inst->getNumOperands(); Idx != E; ++Idx) {
     Value *Opnd = Inst->getOperand(Idx);
 
-    // Vist constant integers.
+    // Visit constant integers.
     if (auto ConstInt = dyn_cast<ConstantInt>(Opnd)) {
-      collectConstantCandidates(Inst, Idx, ConstInt);
+      collectConstantCandidates(ConstCandMap, Inst, Idx, ConstInt);
       continue;
     }
 
@@ -361,7 +363,7 @@ void ConstantHoisting::collectConstantCandidates(Instruction *Inst) {
       if (auto *ConstInt = dyn_cast<ConstantInt>(CastInst->getOperand(0))) {
         // Pretend the constant is directly used by the instruction and ignore
         // the cast instruction.
-        collectConstantCandidates(Inst, Idx, ConstInt);
+        collectConstantCandidates(ConstCandMap, Inst, Idx, ConstInt);
         continue;
       }
     }
@@ -375,7 +377,7 @@ void ConstantHoisting::collectConstantCandidates(Instruction *Inst) {
       if (auto ConstInt = dyn_cast<ConstantInt>(ConstExpr->getOperand(0))) {
         // Pretend the constant is directly used by the instruction and ignore
         // the constant expression.
-        collectConstantCandidates(Inst, Idx, ConstInt);
+        collectConstantCandidates(ConstCandMap, Inst, Idx, ConstInt);
         continue;
       }
     }
@@ -385,9 +387,10 @@ void ConstantHoisting::collectConstantCandidates(Instruction *Inst) {
 /// \brief Collect all integer constants in the function that cannot be folded
 /// into an instruction itself.
 void ConstantHoisting::collectConstantCandidates(Function &Fn) {
+  ConstCandMapType ConstCandMap;
   for (Function::iterator BB : Fn)
     for (BasicBlock::iterator Inst : *BB)
-      collectConstantCandidates(Inst);
+      collectConstantCandidates(ConstCandMap, Inst);
 }
 
 /// \brief Find the base constant within the given range and rebase all other