lsr.patch

commit b8948971566e3742854212b09f83df706e17e475
Author: Nikita Popov <nikita.ppv@gmail.com>
Date:   Sun Dec 6 21:03:04 2020 +0100

    lsr postinc

diff --git a/llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp b/llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp
index c7e37fe0d1b..aa23e244bbc 100644
--- a/llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp
+++ b/llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp
@@ -18,6 +18,7 @@
 #include "llvm/Analysis/InstructionSimplify.h"
 #include "llvm/Analysis/LoopInfo.h"
 #include "llvm/Analysis/TargetTransformInfo.h"
+#include "llvm/Analysis/ValueTracking.h"
 #include "llvm/IR/DataLayout.h"
 #include "llvm/IR/Dominators.h"
 #include "llvm/IR/IntrinsicInst.h"
@@ -1440,6 +1441,10 @@ Value *SCEVExpander::expandAddRecExprLiterally(const SCEVAddRecExpr *S) {
     assert(LatchBlock && "PostInc mode requires a unique loop latch!");
     Result = PN->getIncomingValueForBlock(LatchBlock);
 
+    if (auto *I = dyn_cast<Instruction>(Result))
+      if (!programUndefinedIfPoison(I))
+        I->dropPoisonGeneratingFlags();
+
     // For an expansion to use the postinc form, the client must call
     // expandCodeFor with an InsertPoint that is either outside the PostIncLoop
     // or dominated by IVIncInsertPos.