Implement Jakob's suggestion on how to detect fall thought without calling
AnalyzeBranch.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132981 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index f324148..187963c 100644
--- a/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -1934,19 +1934,26 @@
if (Pred->empty())
return true;
- // 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;
+ // Check the terminators in the previous blocks
+ for (MachineBasicBlock::iterator II = Pred->getFirstTerminator(),
+ IE = Pred->end(); II != IE; ++II) {
+ MachineInstr &MI = *II;
- if (PredTBB == MBB || PredFBB == MBB)
- return false;
+ // If it is not a simple branch, we are in a table somewhere.
+ if (!MI.getDesc().isBranch() || MI.getDesc().isIndirectBranch())
+ return false;
- // This is a fall through if there is no conditions in the bb
- // or if there is no explicit false branch.
- return PredCond.empty() || !PredFBB;
+ // If we are the operands of one of the branches, this is not
+ // a fall through.
+ for (MachineInstr::mop_iterator OI = MI.operands_begin(),
+ OE = MI.operands_end(); OI != OE; ++OI) {
+ const MachineOperand& OP = *OI;
+ if (OP.isMBB() && OP.getMBB() == MBB)
+ return false;
+ }
+ }
+
+ return true;
}