Teach AnalyzeBranch, RemoveBranch and the branch
folder to be tolerant of debug info following the
branch(es) at the end of a block.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@100168 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/BranchFolding.cpp b/lib/CodeGen/BranchFolding.cpp
index 151e9cd..8f51940 100644
--- a/lib/CodeGen/BranchFolding.cpp
+++ b/lib/CodeGen/BranchFolding.cpp
@@ -972,15 +972,21 @@
// MBB1 doesn't, we prefer to fall through into MBB1. This allows us to
// 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 (IsEmptyBlock(MBB1) || IsEmptyBlock(MBB2)) 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();
+ // Neither block consists entirely of debug info (per IsEmptyBlock check),
+ // so we needn't test for falling off the beginning here.
+ MachineBasicBlock::iterator MBB1I = --MBB1->end();
+ while (MBB1I->isDebugValue())
+ --MBB1I;
+ MachineBasicBlock::iterator MBB2I = --MBB2->end();
+ while (MBB2I->isDebugValue())
+ --MBB2I;
return MBB2I->getDesc().isCall() && !MBB1I->getDesc().isCall();
}