When inserting code into a loop preheader, insert it before the

terminator, instead of after the last phi. This fixes a bug
exposed by ScalarEvolution analyzing more kinds of loops.
This fixes PR4436.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@74072 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 6 insertions, 3 deletions

diff --git a/lib/Transforms/Scalar/IndVarSimplify.cpp b/lib/Transforms/Scalar/IndVarSimplify.cpp
index 658b788..ec4be9b 100644
--- a/lib/Transforms/Scalar/IndVarSimplify.cpp
+++ b/lib/Transforms/Scalar/IndVarSimplify.cpp
@@ -230,13 +230,16 @@ void IndVarSimplify::RewriteLoopExitValues(Loop *L,
   // We insert the code into the preheader of the loop if the loop contains
   // multiple exit blocks, or in the exit block if there is exactly one.
   BasicBlock *BlockToInsertInto;
+  BasicBlock::iterator InsertPt;
   SmallVector<BasicBlock*, 8> ExitBlocks;
   L->getUniqueExitBlocks(ExitBlocks);
-  if (ExitBlocks.size() == 1)
+  if (ExitBlocks.size() == 1) {
     BlockToInsertInto = ExitBlocks[0];
-  else
+    InsertPt = BlockToInsertInto->getFirstNonPHI();
+  } else {
     BlockToInsertInto = Preheader;
-  BasicBlock::iterator InsertPt = BlockToInsertInto->getFirstNonPHI();
+    InsertPt = BlockToInsertInto->getTerminator();
+  }
 
   std::map<Instruction*, Value*> ExitValues;