From 56a756821842678a96f2baa8c6a53bd28fc2b69e Mon Sep 17 00:00:00 2001
From: Dan Gohman <gohman@apple.com>
Date: Wed, 17 Nov 2010 23:28:48 +0000
Subject: [PATCH] Factor out the code for purging a SCEV from all the various
 memoization maps. Some of these maps may merge in the future, but for now
 it's convenient to have a utility function for them.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119587 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/Analysis/ScalarEvolution.h |  3 ++
 lib/Analysis/ScalarEvolution.cpp        | 39 +++++++++----------------
 2 files changed, 16 insertions(+), 26 deletions(-)

diff --git a/include/llvm/Analysis/ScalarEvolution.h b/include/llvm/Analysis/ScalarEvolution.h
index 26eceba8152..4ae0f5ae3a2 100644
--- a/include/llvm/Analysis/ScalarEvolution.h
+++ b/include/llvm/Analysis/ScalarEvolution.h
@@ -413,6 +413,9 @@ namespace llvm {
     bool isKnownPredicateWithRanges(ICmpInst::Predicate Pred,
                                     const SCEV *LHS, const SCEV *RHS);
 
+    /// forgetMemoizedResults - Drop memoized information computed for S.
+    void forgetMemoizedResults(const SCEV *S);
+
   public:
     static char ID; // Pass identification, replacement for typeid
     ScalarEvolution();
diff --git a/lib/Analysis/ScalarEvolution.cpp b/lib/Analysis/ScalarEvolution.cpp
index b734d00f7fe..777c1c8ab66 100644
--- a/lib/Analysis/ScalarEvolution.cpp
+++ b/lib/Analysis/ScalarEvolution.cpp
@@ -325,10 +325,7 @@ SCEVSignExtendExpr::SCEVSignExtendExpr(const FoldingSetNodeIDRef ID,
 
 void SCEVUnknown::deleted() {
   // Clear this SCEVUnknown from various maps.
-  SE->ValuesAtScopes.erase(this);
-  SE->LoopDispositions.erase(this);
-  SE->UnsignedRanges.erase(this);
-  SE->SignedRanges.erase(this);
+  SE->forgetMemoizedResults(this);
 
   // Remove this SCEVUnknown from the uniquing map.
   SE->UniqueSCEVs.RemoveNode(this);
@@ -339,10 +336,7 @@ void SCEVUnknown::deleted() {
 
 void SCEVUnknown::allUsesReplacedWith(Value *New) {
   // Clear this SCEVUnknown from various maps.
-  SE->ValuesAtScopes.erase(this);
-  SE->LoopDispositions.erase(this);
-  SE->UnsignedRanges.erase(this);
-  SE->SignedRanges.erase(this);
+  SE->forgetMemoizedResults(this);
 
   // Remove this SCEVUnknown from the uniquing map.
   SE->UniqueSCEVs.RemoveNode(this);
@@ -2636,10 +2630,7 @@ ScalarEvolution::ForgetSymbolicName(Instruction *PN, const SCEV *SymName) {
       if (!isa<PHINode>(I) ||
           !isa<SCEVUnknown>(Old) ||
           (I != PN && Old == SymName)) {
-        ValuesAtScopes.erase(Old);
-        LoopDispositions.erase(Old);
-        UnsignedRanges.erase(Old);
-        SignedRanges.erase(Old);
+        forgetMemoizedResults(Old);
         ValueExprMap.erase(It);
       }
     }
@@ -3677,10 +3668,7 @@ ScalarEvolution::getBackedgeTakenInfo(const Loop *L) {
           // case, createNodeForPHI will perform the necessary updates on its
           // own when it gets to that point.
           if (!isa<PHINode>(I) || !isa<SCEVUnknown>(Old)) {
-            ValuesAtScopes.erase(Old);
-            LoopDispositions.erase(Old);
-            UnsignedRanges.erase(Old);
-            SignedRanges.erase(Old);
+            forgetMemoizedResults(Old);
             ValueExprMap.erase(It);
           }
           if (PHINode *PN = dyn_cast<PHINode>(I))
@@ -3712,11 +3700,7 @@ void ScalarEvolution::forgetLoop(const Loop *L) {
 
     ValueExprMapType::iterator It = ValueExprMap.find(static_cast<Value *>(I));
     if (It != ValueExprMap.end()) {
-      const SCEV *Old = It->second;
-      ValuesAtScopes.erase(Old);
-      LoopDispositions.erase(Old);
-      UnsignedRanges.erase(Old);
-      SignedRanges.erase(Old);
+      forgetMemoizedResults(It->second);
       ValueExprMap.erase(It);
       if (PHINode *PN = dyn_cast<PHINode>(I))
         ConstantEvolutionLoopExitValue.erase(PN);
@@ -3749,11 +3733,7 @@ void ScalarEvolution::forgetValue(Value *V) {
 
     ValueExprMapType::iterator It = ValueExprMap.find(static_cast<Value *>(I));
     if (It != ValueExprMap.end()) {
-      const SCEV *Old = It->second;
-      ValuesAtScopes.erase(Old);
-      LoopDispositions.erase(Old);
-      UnsignedRanges.erase(Old);
-      SignedRanges.erase(Old);
+      forgetMemoizedResults(It->second);
       ValueExprMap.erase(It);
       if (PHINode *PN = dyn_cast<PHINode>(I))
         ConstantEvolutionLoopExitValue.erase(PN);
@@ -6141,3 +6121,10 @@ bool ScalarEvolution::hasOperand(const SCEV *S, const SCEV *Op) const {
   llvm_unreachable("Unknown SCEV kind!");
   return false;
 }
+
+void ScalarEvolution::forgetMemoizedResults(const SCEV *S) {
+  ValuesAtScopes.erase(S);
+  LoopDispositions.erase(S);
+  UnsignedRanges.erase(S);
+  SignedRanges.erase(S);
+}
-- 
2.34.1