[LoopUnroll] Simplify induction variables after peeling too.

Loop peeling also has an impact on the induction variables, so we should
benefit from induction variable simplification after peeling too.

Reviewers: sanjoy, bogner, mzolotukhin, efriedma

Reviewed By: efriedma

Differential Revision: https://reviews.llvm.org/D43878

llvm-svn: 328301

1 files changed, 3 insertions, 2 deletions

diff --git a/llvm/lib/Transforms/Utils/LoopUnroll.cpp b/llvm/lib/Transforms/Utils/LoopUnroll.cpp
index 506edf945eb..9fb7d68e5fd 100644
--- a/llvm/lib/Transforms/Utils/LoopUnroll.cpp
+++ b/llvm/lib/Transforms/Utils/LoopUnroll.cpp
@@ -403,8 +403,9 @@ LoopUnrollResult llvm::UnrollLoop(
          "Did not expect runtime trip-count unrolling "
          "and peeling for the same loop");
 
+  bool Peeled = false;
   if (PeelCount) {
-    bool Peeled = peelLoop(L, PeelCount, LI, SE, DT, AC, PreserveLCSSA);
+    Peeled = peelLoop(L, PeelCount, LI, SE, DT, AC, PreserveLCSSA);
 
     // Successful peeling may result in a change in the loop preheader/trip
     // counts. If we later unroll the loop, we want these to be updated.
@@ -790,7 +791,7 @@ LoopUnrollResult llvm::UnrollLoop(
   }
 
   // Simplify any new induction variables in the partially unrolled loop.
-  if (SE && !CompletelyUnroll && Count > 1) {
+  if (SE && !CompletelyUnroll && (Count > 1 || Peeled)) {
     SmallVector<WeakTrackingVH, 16> DeadInsts;
     simplifyLoopIVs(L, SE, DT, LI, DeadInsts);