Unreachable block is not a root node in post dominator tree.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@40458 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/PostDominators.cpp b/lib/Analysis/PostDominators.cpp
index 48f7b30..1188cff 100644
--- a/lib/Analysis/PostDominators.cpp
+++ b/lib/Analysis/PostDominators.cpp
@@ -112,8 +112,12 @@
// relationships. These blocks, which have no successors, end with return and
// unwind instructions.
for (Function::iterator I = F.begin(), E = F.end(); I != E; ++I)
- if (succ_begin(I) == succ_end(I))
- Roots.push_back(I);
+ if (succ_begin(I) == succ_end(I)) {
+ Instruction *Insn = I->getTerminator();
+ // Unreachable block is not a root node.
+ if (!isa<UnreachableInst>(Insn))
+ Roots.push_back(I);
+ }
Vertex.push_back(0);
diff --git a/test/Transforms/ADCE/2007-07-23-InfiniteLoop.ll b/test/Transforms/ADCE/2007-07-23-InfiniteLoop.ll
new file mode 100644
index 0000000..f3500ed
--- /dev/null
+++ b/test/Transforms/ADCE/2007-07-23-InfiniteLoop.ll
@@ -0,0 +1,13 @@
+; RUN: llvm-as < %s | opt -adce | llvm-dis | grep switch
+; PR 1564
+
+define fastcc void @out() {
+ start:
+ br label %loop
+ unreachable:
+ unreachable
+ loop:
+ switch i32 0, label %unreachable [
+ i32 0, label %loop
+ ]
+}