From 4b105912657c0472dc4f6f7244ce20bf7cf9a7dc Mon Sep 17 00:00:00 2001
From: Chris Lattner <sabre@nondot.org>
Date: Sat, 18 Nov 2006 22:25:39 +0000
Subject: [PATCH] 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
---
lib/CodeGen/BranchFolding.cpp | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
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;