Simplify the construction and destruction of Uses. Simplify

User::dropHungOffUses().

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123580 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 15 insertions, 24 deletions

diff --git a/lib/VMCore/Instructions.cpp b/lib/VMCore/Instructions.cpp
index 909dab9..db38a15 100644
--- a/lib/VMCore/Instructions.cpp
+++ b/lib/VMCore/Instructions.cpp
@@ -96,8 +96,7 @@ PHINode::PHINode(const PHINode &PN)
 }
 
 PHINode::~PHINode() {
-  if (OperandList)
-    dropHungoffUses(OperandList);
+  dropHungoffUses();
 }
 
 // removeIncomingValue - Remove an incoming value.  This is useful if a
@@ -158,7 +157,7 @@ void PHINode::resizeOperands(unsigned NumOps) {
   Use *NewOps = allocHungoffUses(NumOps);
   std::copy(OldOps, OldOps + e, NewOps);
   OperandList = NewOps;
-  if (OldOps) Use::zap(OldOps, OldOps + e, true);
+  Use::zap(OldOps, OldOps + e, true);
 }
 
 /// hasConstantValue - If the specified PHI node always merges together the same
@@ -2982,7 +2981,7 @@ SwitchInst::SwitchInst(const SwitchInst &SI)
 }
 
 SwitchInst::~SwitchInst() {
-  dropHungoffUses(OperandList);
+  dropHungoffUses();
 }
 
 
@@ -3053,7 +3052,7 @@ void SwitchInst::resizeOperands(unsigned NumOps) {
       NewOps[i] = OldOps[i];
   }
   OperandList = NewOps;
-  if (OldOps) Use::zap(OldOps, OldOps + e, true);
+  Use::zap(OldOps, OldOps + e, true);
 }
 
 
@@ -3068,7 +3067,7 @@ void SwitchInst::setSuccessorV(unsigned idx, BasicBlock *B) {
 }
 
 //===----------------------------------------------------------------------===//
-//                        SwitchInst Implementation
+//                        IndirectBrInst Implementation
 //===----------------------------------------------------------------------===//
 
 void IndirectBrInst::init(Value *Address, unsigned NumDests) {
@@ -3108,7 +3107,7 @@ void IndirectBrInst::resizeOperands(unsigned NumOps) {
   for (unsigned i = 0; i != e; ++i)
     NewOps[i] = OldOps[i];
   OperandList = NewOps;
-  if (OldOps) Use::zap(OldOps, OldOps + e, true);
+  Use::zap(OldOps, OldOps + e, true);
 }
 
 IndirectBrInst::IndirectBrInst(Value *Address, unsigned NumCases,
@@ -3136,7 +3135,7 @@ IndirectBrInst::IndirectBrInst(const IndirectBrInst &IBI)
 }
 
 IndirectBrInst::~IndirectBrInst() {
-  dropHungoffUses(OperandList);
+  dropHungoffUses();
 }
 
 /// addDestination - Add a destination.
diff --git a/lib/VMCore/Use.cpp b/lib/VMCore/Use.cpp
index 32cf954..4e959a5 100644
--- a/lib/VMCore/Use.cpp
+++ b/lib/VMCore/Use.cpp
@@ -85,7 +85,8 @@ const Use *Use::getImpliedUser() const {
 //                         Use initTags Implementation
 //===----------------------------------------------------------------------===//
 
-Use *Use::initTags(Use * const Start, Use *Stop, ptrdiff_t Done) {
+Use *Use::initTags(Use * const Start, Use *Stop) {
+  ptrdiff_t Done = 0;
   while (Done < 20) {
     if (Start == Stop--)
       return Start;
@@ -97,20 +98,18 @@ Use *Use::initTags(Use * const Start, Use *Stop, ptrdiff_t Done) {
                                          oneDigitTag, oneDigitTag, oneDigitTag,
                                          oneDigitTag, stopTag
                                        };
-    Stop->Prev.setFromOpaqueValue(reinterpret_cast<Use**>(tags[Done++]));
-    Stop->Val = 0;
+    new(Stop) Use(tags[Done++]);
   }
 
   ptrdiff_t Count = Done;
   while (Start != Stop) {
     --Stop;
-    Stop->Val = 0;
     if (!Count) {
-      Stop->Prev.setFromOpaqueValue(reinterpret_cast<Use**>(stopTag));
+      new(Stop) Use(stopTag);
       ++Done;
       Count = Done;
     } else {
-      Stop->Prev.setFromOpaqueValue(reinterpret_cast<Use**>(Count & 1));
+      new(Stop) Use(PrevPtrTag(Count & 1));
       Count >>= 1;
       ++Done;
     }
@@ -124,17 +123,10 @@ Use *Use::initTags(Use * const Start, Use *Stop, ptrdiff_t Done) {
 //===----------------------------------------------------------------------===//
 
 void Use::zap(Use *Start, const Use *Stop, bool del) {
-  if (del) {
-    while (Start != Stop) {
-      (--Stop)->~Use();
-    }
+  while (Start != Stop)
+    (--Stop)->~Use();
+  if (del)
     ::operator delete(Start);
-    return;
-  }
-
-  while (Start != Stop) {
-    (Start++)->set(0);
-  }
 }
 
 //===----------------------------------------------------------------------===//