[FuzzMutate] Bailout from injecting into empty basic blocks.
In rare cases we can receive request to inject into completelly empty basic block. In the normal case
all basic blocks contain at least terminator instruction, but it is possible that the only instruction is
catchpad instruction which is not part of the instruction iterator. This case seems rare enough to not care
about it.
Submiting without review, since it seems almost NFC. I couldn't come up with any reasonable way to test this.
llvm-svn: 319444
diff --git a/llvm/lib/FuzzMutate/IRMutator.cpp b/llvm/lib/FuzzMutate/IRMutator.cpp
index 59f9471..15e7f86 100644
--- a/llvm/lib/FuzzMutate/IRMutator.cpp
+++ b/llvm/lib/FuzzMutate/IRMutator.cpp
@@ -105,6 +105,8 @@
SmallVector<Instruction *, 32> Insts;
for (auto I = BB.getFirstInsertionPt(), E = BB.end(); I != E; ++I)
Insts.push_back(&*I);
+ if (Insts.size() < 1)
+ return;
// Choose an insertion point for our new instruction.
size_t IP = uniform<size_t>(IB.Rand, 0, Insts.size() - 1);