From: Chris Lattner <sabre@nondot.org>
Date: Sat, 18 Nov 2006 22:25:39 +0000 (+0000)
Subject: Don't transform in another bad case: if the block is empty, it should be
X-Git-Url: http://plrg.eecs.uci.edu/git/?a=commitdiff_plain;h=4b105912657c0472dc4f6f7244ce20bf7cf9a7dc;p=oota-llvm.git

Don't transform in another bad case: if the block is empty, it should be
simplified before we do this xform so that our cost model is accurate.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31864 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/CodeGen/BranchFolding.cpp b/lib/CodeGen/BranchFolding.cpp
index c69930da81e..8ded3cdc64d 100644
--- a/lib/CodeGen/BranchFolding.cpp
+++ b/lib/CodeGen/BranchFolding.cpp
@@ -729,7 +729,8 @@ void BranchFolder::OptimizeBlock(MachineBasicBlock *MBB) {
       //
       // In this case, we could actually be moving the return block *into* a
       // loop!
-      if (DoTransform && !MBB->succ_empty() && !CanFallThrough(PriorTBB))
+      if (DoTransform && !MBB->succ_empty() &&
+          (!CanFallThrough(PriorTBB) || PriorTBB->empty()))
         DoTransform = false;