Fix SCEVExpander to handle loops with no preheader when LSR gives it a

"phony" insertion point.

Fixes rdar://10619599: "SelectionDAGBuilder shouldn't visit PHI nodes!" assert


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147439 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 6 insertions, 0 deletions

diff --git a/lib/Analysis/ScalarEvolutionExpander.cpp b/lib/Analysis/ScalarEvolutionExpander.cpp
index 5f83914cb2..0a3cda998f 100644
--- a/lib/Analysis/ScalarEvolutionExpander.cpp
+++ b/lib/Analysis/ScalarEvolutionExpander.cpp
@@ -1443,6 +1443,12 @@ Value *SCEVExpander::expand(const SCEV *S) {
       if (!L) break;
       if (BasicBlock *Preheader = L->getLoopPreheader())
         InsertPt = Preheader->getTerminator();
+      else {
+        // LSR sets the insertion point for AddRec start/step values to the
+        // block start to simplify value reuse, even though it's an invalid
+        // position. SCEVExpander must correct for this in all cases.
+        InsertPt = L->getHeader()->getFirstInsertionPt();
+      }
     } 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