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-rw-r--r--lib/CodeGen/BranchFolding.cpp5
-rw-r--r--test/CodeGen/X86/2007-06-14-branchfold.ll4
2 files changed, 6 insertions, 3 deletions
diff --git a/lib/CodeGen/BranchFolding.cpp b/lib/CodeGen/BranchFolding.cpp
index d4b1e90..0f8c662 100644
--- a/lib/CodeGen/BranchFolding.cpp
+++ b/lib/CodeGen/BranchFolding.cpp
@@ -775,6 +775,11 @@ static bool IsBetterFallthrough(MachineBasicBlock *MBB1,
// optimize branches that branch to either a return block or an assert block
// into a fallthrough to the return.
if (MBB1->empty() || MBB2->empty()) return false;
+
+ // If there is a clear successor ordering we make sure that one block
+ // will fall through to the next
+ if (MBB1->isSuccessor(MBB2)) return true;
+ if (MBB2->isSuccessor(MBB1)) return false;
MachineInstr *MBB1I = --MBB1->end();
MachineInstr *MBB2I = --MBB2->end();
diff --git a/test/CodeGen/X86/2007-06-14-branchfold.ll b/test/CodeGen/X86/2007-06-14-branchfold.ll
index b78c63d..697d6a3 100644
--- a/test/CodeGen/X86/2007-06-14-branchfold.ll
+++ b/test/CodeGen/X86/2007-06-14-branchfold.ll
@@ -1,7 +1,5 @@
-; RUN: llvm-as < %s | llc -mcpu=i686 | grep jmp | count 1
+; RUN: llvm-as < %s | llc -mcpu=i686 | not grep jmp
; check that branch folding understands FP_REG_KILL is not a branch
-; the remaining jmp can be removed if we take advantage of knowing
-; abort does not return
; ModuleID = 'g.bc'
target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64"