Fix another case where LSR was affected by debug info.

llvm-svn: 97865

1 files changed, 12 insertions, 1 deletions

diff --git a/llvm/lib/Analysis/ScalarEvolutionExpander.cpp b/llvm/lib/Analysis/ScalarEvolutionExpander.cpp
index 5808c75fd39..e27da966924 100644
--- a/llvm/lib/Analysis/ScalarEvolutionExpander.cpp
+++ b/llvm/lib/Analysis/ScalarEvolutionExpander.cpp
@@ -1267,8 +1267,19 @@ Value *SCEVExpander::expand(const SCEV *S) {
        L = L->getParentLoop())
     if (S->isLoopInvariant(L)) {
       if (!L) break;
-      if (BasicBlock *Preheader = L->getLoopPreheader())
+      if (BasicBlock *Preheader = L->getLoopPreheader()) {
         InsertPt = Preheader->getTerminator();
+        BasicBlock::iterator IP = InsertPt;
+        // Back past any debug info instructions.  Sometimes we inserted
+        // something earlier before debug info but after any real instructions.
+        // This should behave the same as if debug info was not present.
+        while (IP != Preheader->begin()) {
+          --IP;
+          if (!isa<DbgInfoIntrinsic>(IP))
+            break;
+          InsertPt = IP;
+        }
+      }
     } else {
       // If the SCEV is computable at this level, insert it into the header
       // after the PHIs (and after any other instructions that we've inserted