Remove the Expr member from IVUsers. Instead of remembering the expression,

just ask ScalarEvolution for it on demand. This helps IVUsers be more robust
in the case of expressions changing underneath it. This fixes PR6862.

llvm-svn: 101819

1 files changed, 5 insertions, 6 deletions

diff --git a/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp b/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
index 19f78f424ce..a09bca89976 100644
--- a/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
@@ -1575,8 +1575,8 @@ LSRInstance::OptimizeLoopTermCond() {
             !DT.properlyDominates(UI->getUser()->getParent(), ExitingBlock)) {
           // Conservatively assume there may be reuse if the quotient of their
           // strides could be a legal scale.
-          const SCEV *A = CondUse->getStride(L);
-          const SCEV *B = UI->getStride(L);
+          const SCEV *A = IU.getStride(*CondUse, L);
+          const SCEV *B = IU.getStride(*UI, L);
           if (!A || !B) continue;
           if (SE.getTypeSizeInBits(A->getType()) !=
               SE.getTypeSizeInBits(B->getType())) {
@@ -1629,8 +1629,7 @@ LSRInstance::OptimizeLoopTermCond() {
         ExitingBlock->getInstList().insert(TermBr, Cond);
 
         // Clone the IVUse, as the old use still exists!
-        CondUse = &IU.AddUser(CondUse->getExpr(),
-                              Cond, CondUse->getOperandValToReplace());
+        CondUse = &IU.AddUser(Cond, CondUse->getOperandValToReplace());
         TermBr->replaceUsesOfWith(OldCond, Cond);
       }
     }
@@ -1748,7 +1747,7 @@ void LSRInstance::CollectInterestingTypesAndFactors() {
   // Collect interesting types and strides.
   SmallVector<const SCEV *, 4> Worklist;
   for (IVUsers::const_iterator UI = IU.begin(), E = IU.end(); UI != E; ++UI) {
-    const SCEV *Expr = UI->getExpr();
+    const SCEV *Expr = IU.getExpr(*UI);
 
     // Collect interesting types.
     Types.insert(SE.getEffectiveSCEVType(Expr->getType()));
@@ -1819,7 +1818,7 @@ void LSRInstance::CollectFixupsAndInitialFormulae() {
       AccessTy = getAccessType(LF.UserInst);
     }
 
-    const SCEV *S = UI->getExpr();
+    const SCEV *S = IU.getExpr(*UI);
 
     // Equality (== and !=) ICmps are special. We can rewrite (i == N) as
     // (N - i == 0), and this allows (N - i) to be the expression that we work