AnalyzeBranch doesn't change which successors a bb has, just the order
we try to branch to them.
Before we were creating successor lists with duplicated entries. Fixing that
found a bug in isBlockOnlyReachableByFallthrough that would causes it to
return the wrong answer for
-----------
...
jne foo
jmp bar
foo:
----------
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132882 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index 161afba..1fd724f 100644
--- a/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -1925,7 +1925,7 @@
return false;
// The predecessor has to be immediately before this block.
- const MachineBasicBlock *Pred = *PI;
+ MachineBasicBlock *Pred = *PI;
if (!Pred->isLayoutSuccessor(MBB))
return false;
@@ -1934,9 +1934,16 @@
if (Pred->empty())
return true;
- // Otherwise, check the last instruction.
- const MachineInstr &LastInst = Pred->back();
- return !LastInst.getDesc().isBarrier();
+ // Otherwise, ask the backend.
+ const TargetInstrInfo *TII = MF->getTarget().getInstrInfo();
+ MachineBasicBlock *PredTBB = NULL, *PredFBB = NULL;
+ SmallVector<MachineOperand, 4> PredCond;
+ if (TII->AnalyzeBranch(*Pred, PredTBB, PredFBB, PredCond))
+ return false;
+
+ if (PredCond.empty())
+ return true;
+ return !PredFBB || PredFBB == MBB;
}