[MachineBasicBlock] Make the pass argument truly mandatory when

splitting edges.

MachineBasicBlock::SplitCriticalEdges will crash if a nullptr would have
been passed for the Pass argument. Do not allow that by turning this
argument into a reference.
The alternative would have been to make the Pass a truly optional
argument, but although this is easy to do, I was afraid users using it
like this would not be aware the livness information, dominator tree and
such would silently be broken.

llvm-svn: 267052

1 files changed, 1 insertions, 1 deletions

diff --git a/llvm/lib/CodeGen/PHIElimination.cpp b/llvm/lib/CodeGen/PHIElimination.cpp
index 4a0c1633308..9cbb318f0c8 100644
--- a/llvm/lib/CodeGen/PHIElimination.cpp
+++ b/llvm/lib/CodeGen/PHIElimination.cpp
@@ -610,7 +610,7 @@ bool PHIElimination::SplitPHIEdges(MachineFunction &MF,
       }
       if (!ShouldSplit && !SplitAllCriticalEdges)
         continue;
-      if (!PreMBB->SplitCriticalEdge(&MBB, this)) {
+      if (!PreMBB->SplitCriticalEdge(&MBB, *this)) {
         DEBUG(dbgs() << "Failed to split critical edge.\n");
         continue;
       }