[PATCH] D13458: [SCEV] Pick backedge values for phi nodes correctly

[Philip Reames via llvm-commits]

reames added a subscriber: reames.
reames accepted this revision.
reames added a reviewer: reames.
reames added a comment.
This revision is now accepted and ready to land.

LGTM.


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Comment at: lib/Analysis/ScalarEvolution.cpp:5745
@@ +5744,3 @@
+  // NonLatch is the preheader, or something equivalent.
+  BasicBlock *NonLatch = Latch == PN->getIncomingBlock(0)
+                             ? PN->getIncomingBlock(1)
----------------
This line should probably be below the following comment.

================
Comment at: lib/Analysis/ScalarEvolution.cpp:5759
@@ -5747,3 +5758,3 @@
     auto *StartCST =
-      dyn_cast<Constant>(PHI->getIncomingValue(!SecondIsBackedge));
+        dyn_cast<Constant>(PHI->getIncomingValueForBlock(NonLatch));
     if (!StartCST) continue;
----------------
Please put a comment that says not all phis have to list their arguments in the same order.  This is subtle and easily confused.


http://reviews.llvm.org/D13458