Fix PR6047

Nodes that had children outside of the post dominator tree (infinite loops)
where removed from the post dominator tree. This seems to be wrong. Leave them
in the tree.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@93633 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Analysis/DominatorInternals.h

@@ -262,29 +262,17 @@ void Calculate(DominatorTreeBase<typename GraphTraits<NodeT>::NodeType>& DT,
                                                                      DT.Info[W];
 
     // Step #2: Calculate the semidominators of all vertices
-    bool HasChildOutsideDFS = false;
 
     // initialize the semi dominator to point to the parent node
     WInfo.Semi = WInfo.Parent;
     for (typename GraphTraits<Inverse<NodeT> >::ChildIteratorType CI =
          GraphTraits<Inverse<NodeT> >::child_begin(W),
-         E = GraphTraits<Inverse<NodeT> >::child_end(W); CI != E; ++CI) {
+         E = GraphTraits<Inverse<NodeT> >::child_end(W); CI != E; ++CI)
       if (DT.Info.count(*CI)) {  // Only if this predecessor is reachable!
         unsigned SemiU = DT.Info[Eval<GraphT>(DT, *CI)].Semi;
         if (SemiU < WInfo.Semi)
           WInfo.Semi = SemiU;
       }
-      else {
-        // if the child has no DFS number it is not post-dominated by any exit, 
-        // and so is the current block.
-        HasChildOutsideDFS = true;
-      }
-    }
-
-    // if some child has no DFS number it is not post-dominated by any exit, 
-    // and so is the current block.
-    if (DT.isPostDominator() && HasChildOutsideDFS)
-      WInfo.Semi = 0;
 
     DT.Info[DT.Vertex[WInfo.Semi]].Bucket.push_back(W);
 

test/Analysis/PostDominators/pr6047_a.ll

@@ -0,0 +1,15 @@
+; RUN: opt < %s -postdomtree -analyze | FileCheck %s
+define internal void @f() {
+entry:
+  br i1 undef, label %bb35, label %bb3.i
+
+bb3.i:
+  br label %bb3.i
+
+bb35.loopexit3:
+  br label %bb35
+
+bb35:
+  ret void
+}
+; CHECK: [3] %entry

test/Analysis/PostDominators/pr6047_b.ll

@@ -0,0 +1,19 @@
+; RUN: opt < %s -postdomtree -analyze | FileCheck %s
+define internal void @f() {
+entry:
+  br i1 undef, label %a, label %bb3.i
+
+a:
+  br i1 undef, label %bb35, label %bb3.i
+
+bb3.i:
+  br label %bb3.i
+
+
+bb35.loopexit3:
+  br label %bb35
+
+bb35:
+  ret void
+}
+; CHECK: [4] %entry

test/Analysis/PostDominators/pr6047_c.ll

@@ -0,0 +1,147 @@
+; RUN: opt < %s -postdomtree -analyze | FileCheck %s
+define internal void @f() {
+entry:
+  br i1 undef, label %bb35, label %bb3.i
+
+bb3.i:
+  br label %bb3.i
+
+bb:
+  br label %bb35
+
+bb.i:
+  br label %bb35
+
+_float32_unpack.exit:
+  br label %bb35
+
+bb.i5:
+  br label %bb35
+
+_float32_unpack.exit8:
+  br label %bb35
+
+bb32.preheader:
+  br label %bb35
+
+bb3:
+  br label %bb35
+
+bb3.split.us:
+  br label %bb35
+
+bb.i4.us:
+  br label %bb35
+
+bb7.i.us:
+  br label %bb35
+
+bb.i4.us.backedge:
+  br label %bb35
+
+bb1.i.us:
+  br label %bb35
+
+bb6.i.us:
+  br label %bb35
+
+bb4.i.us:
+  br label %bb35
+
+bb8.i.us:
+  br label %bb35
+
+bb3.i.loopexit.us:
+  br label %bb35
+
+bb.nph21:
+  br label %bb35
+
+bb4:
+  br label %bb35
+
+bb5:
+  br label %bb35
+
+bb14.preheader:
+  br label %bb35
+
+bb.nph18:
+  br label %bb35
+
+bb8.us.preheader:
+  br label %bb35
+
+bb8.preheader:
+  br label %bb35
+
+bb8.us:
+  br label %bb35
+
+bb8:
+  br label %bb35
+
+bb15.loopexit:
+  br label %bb35
+
+bb15.loopexit2:
+  br label %bb35
+
+bb15:
+  br label %bb35
+
+bb16:
+  br label %bb35
+
+bb17.loopexit.split:
+  br label %bb35
+
+bb.nph14:
+  br label %bb35
+
+bb19:
+  br label %bb35
+
+bb20:
+  br label %bb35
+
+bb29.preheader:
+  br label %bb35
+
+bb.nph:
+  br label %bb35
+
+bb23.us.preheader:
+  br label %bb35
+
+bb23.preheader:
+  br label %bb35
+
+bb23.us:
+  br label %bb35
+
+bb23:
+  br label %bb35
+
+bb30.loopexit:
+  br label %bb35
+
+bb30.loopexit1:
+  br label %bb35
+
+bb30:
+  br label %bb35
+
+bb31:
+  br label %bb35
+
+bb35.loopexit:
+  br label %bb35
+
+bb35.loopexit3:
+  br label %bb35
+
+bb35:
+  ret void
+}
+; CHECK: [3] %entry

test/Analysis/PostDominators/pr6047_d.ll

@@ -0,0 +1,24 @@
+; RUN: opt < %s -postdomtree -analyze | FileCheck %s
+define internal void @f() {
+entry:
+  br i1 1, label %a, label %b
+
+a:
+br label %c
+
+b:
+br label %c
+
+c:
+  br i1 undef, label %bb35, label %bb3.i
+
+bb3.i:
+  br label %bb3.i
+
+bb35.loopexit3:
+  br label %bb35
+
+bb35:
+  ret void
+}
+; CHECK: [4] %entry