Revert r230280: "Bugfix: SCEVExpander incorrectly marks increment operations as no-wrap"

This caused PR22674, failing this assert:

Instructions.h:2281: llvm::Value* llvm::PHINode::getOperand(unsigned int) const: Assertion `i_nocapture < OperandTraits<PHINode>::operands(this) && "getOperand() out of range!"' failed.

llvm-svn: 230341

1 files changed, 2 insertions, 31 deletions

diff --git a/llvm/lib/Analysis/ScalarEvolutionExpander.cpp b/llvm/lib/Analysis/ScalarEvolutionExpander.cpp
index ef9557132fc..59f19a002ec 100644
--- a/llvm/lib/Analysis/ScalarEvolutionExpander.cpp
+++ b/llvm/lib/Analysis/ScalarEvolutionExpander.cpp
@@ -1063,34 +1063,6 @@ static bool canBeCheaplyTransformed(ScalarEvolution &SE,
   return false;
 }
 
-static bool IsIncrementNSW(ScalarEvolution &SE, const SCEVAddRecExpr *AR) {
-  if (!isa<IntegerType>(AR->getType()))
-    return false;
-
-  unsigned BitWidth = cast<IntegerType>(AR->getType())->getBitWidth();
-  Type *WideTy = IntegerType::get(AR->getType()->getContext(), BitWidth * 2);
-  const SCEV *Step = AR->getStepRecurrence(SE);
-  const SCEV *OpAfterExtend = SE.getAddExpr(SE.getSignExtendExpr(Step, WideTy),
-                                            SE.getSignExtendExpr(AR, WideTy));
-  const SCEV *ExtendAfterOp =
-    SE.getSignExtendExpr(SE.getAddExpr(AR, Step), WideTy);
-  return ExtendAfterOp == OpAfterExtend;
-}
-
-static bool IsIncrementNUW(ScalarEvolution &SE, const SCEVAddRecExpr *AR) {
-  if (!isa<IntegerType>(AR->getType()))
-    return false;
-
-  unsigned BitWidth = cast<IntegerType>(AR->getType())->getBitWidth();
-  Type *WideTy = IntegerType::get(AR->getType()->getContext(), BitWidth * 2);
-  const SCEV *Step = AR->getStepRecurrence(SE);
-  const SCEV *OpAfterExtend = SE.getAddExpr(SE.getZeroExtendExpr(Step, WideTy),
-                                            SE.getZeroExtendExpr(AR, WideTy));
-  const SCEV *ExtendAfterOp =
-    SE.getZeroExtendExpr(SE.getAddExpr(AR, Step), WideTy);
-  return ExtendAfterOp == OpAfterExtend;
-}
-
 /// getAddRecExprPHILiterally - Helper for expandAddRecExprLiterally. Expand
 /// the base addrec, which is the addrec without any non-loop-dominating
 /// values, and return the PHI.
@@ -1241,11 +1213,10 @@ SCEVExpander::getAddRecExprPHILiterally(const SCEVAddRecExpr *Normalized,
       IVIncInsertPos : Pred->getTerminator();
     Builder.SetInsertPoint(InsertPos);
     Value *IncV = expandIVInc(PN, StepV, L, ExpandTy, IntTy, useSubtract);
-
     if (isa<OverflowingBinaryOperator>(IncV)) {
-      if (IsIncrementNUW(SE, Normalized))
+      if (Normalized->getNoWrapFlags(SCEV::FlagNUW))
         cast<BinaryOperator>(IncV)->setHasNoUnsignedWrap();
-      if (IsIncrementNSW(SE, Normalized))
+      if (Normalized->getNoWrapFlags(SCEV::FlagNSW))
         cast<BinaryOperator>(IncV)->setHasNoSignedWrap();
     }
     PN->addIncoming(IncV, Pred);