When moving a block for table jumps, make sure the prior block terminator
is analyzable so it can be updated. If it's not, be safe and don't move the
block.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89022 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/ARMConstantIslandPass.cpp b/lib/Target/ARM/ARMConstantIslandPass.cpp
index 0eb7227..734e33d 100644
--- a/lib/Target/ARM/ARMConstantIslandPass.cpp
+++ b/lib/Target/ARM/ARMConstantIslandPass.cpp
@@ -1749,21 +1749,23 @@
// heuristic. FIXME: We can definitely improve it.
MachineBasicBlock *TBB = 0, *FBB = 0;
SmallVector<MachineOperand, 4> Cond;
+ SmallVector<MachineOperand, 4> CondPrior;
+ MachineFunction::iterator BBi = BB;
+ MachineFunction::iterator OldPrior = prior(BBi);
// If the block terminator isn't analyzable, don't try to move the block
- if (TII->AnalyzeBranch(*BB, TBB, FBB, Cond))
- return NULL;
+ bool B = TII->AnalyzeBranch(*BB, TBB, FBB, Cond);
- // If the block ends in an unconditional branch, move it. Be paranoid
+ // If the block ends in an unconditional branch, move it. The prior block
+ // has to have an analyzable terminator for us to move this one. Be paranoid
// and make sure we're not trying to move the entry block of the function.
- if (Cond.empty() && BB != MF.begin()) {
- MachineFunction::iterator BBi = BB;
- MachineFunction::iterator OldPrior = prior(BBi);
+ if (!B && Cond.empty() && BB != MF.begin() &&
+ !TII->AnalyzeBranch(*OldPrior, TBB, FBB, CondPrior)) {
BB->moveAfter(JTBB);
OldPrior->updateTerminator();
BB->updateTerminator();
// Update numbering to account for the block being moved.
- MF.RenumberBlocks(OldPrior);
+ MF.RenumberBlocks();
++NumJTMoved;
return NULL;
}