[PATCH] D48597: [LoopInstSimplify] Discard SCEV if simplification happened.

[Roman Lebedev via Phabricator via llvm-commits]

lebedev.ri added a comment.

In https://reviews.llvm.org/D48597#1143645, @sanjoy wrote:

> IMO this doesn't seem like an invalidation bug -- SCEV Expander needs to be smarter about dealing with these kinds of simplifications.


Does this sound better?

  diff --git a/lib/Analysis/ScalarEvolutionExpander.cpp b/lib/Analysis/ScalarEvolutionExpander.cpp
  index f2ce0f4aa86..2058e591a77 100644
  --- a/lib/Analysis/ScalarEvolutionExpander.cpp
  +++ b/lib/Analysis/ScalarEvolutionExpander.cpp
  @@ -1169,8 +1169,10 @@ SCEVExpander::getAddRecExprPHILiterally(const SCEVAddRecExpr *Normalized,
         if (!IsMatchingSCEV && !TryNonMatchingSCEV)
             continue;
   
  -      Instruction *TempIncV =
  -          cast<Instruction>(PN.getIncomingValueForBlock(LatchBlock));
  +      Value* IncomingValue = PN.getIncomingValueForBlock(LatchBlock);
  +      if(!isa<Instruction>(IncomingValue))
  +        continue;
  +      Instruction *TempIncV = cast<Instruction>(IncomingValue);
   
         // Check whether we can reuse this PHI node.
         if (LSRMode) {


Repository:
  rL LLVM

https://reviews.llvm.org/D48597