Pull in r230058 from upstream llvm trunk (by Benjamin Kramer):

  LoopRotate: When reconstructing loop simplify form don't split edges
  from indirectbrs.

  Yet another chapter in the endless story. While this looks like we
  leave the loop in a non-canonical state this replicates the logic in
  LoopSimplify so it doesn't diverge from the canonical form in any way.

  PR21968

This fixes a "Cannot split critical edge from IndirectBrInst" assertion
failure when building the devel/radare2 port.

Introduced here: https://svnweb.freebsd.org/changeset/base/279161

Index: lib/Transforms/Scalar/LoopRotation.cpp
===================================================================
--- lib/Transforms/Scalar/LoopRotation.cpp
+++ lib/Transforms/Scalar/LoopRotation.cpp
@@ -535,6 +535,8 @@ bool LoopRotate::rotateLoop(Loop *L, bool Simplifi
       Loop *PredLoop = LI->getLoopFor(*PI);
       if (!PredLoop || PredLoop->contains(Exit))
         continue;
+      if (isa<IndirectBrInst>((*PI)->getTerminator()))
+        continue;
       SplitLatchEdge |= L->getLoopLatch() == *PI;
       BasicBlock *ExitSplit = SplitCriticalEdge(*PI, Exit, this);
       ExitSplit->moveBefore(Exit);
Index: test/Transforms/LoopRotate/crash.ll
===================================================================
--- test/Transforms/LoopRotate/crash.ll
+++ test/Transforms/LoopRotate/crash.ll
@@ -153,3 +153,21 @@ entry:
 "5":                                              ; preds = %"3", %entry
   ret void
 }
+
+; PR21968
+define void @test8(i1 %C, i8* %P) #0 {
+entry:
+  br label %for.cond
+
+for.cond:                                         ; preds = %for.inc, %entry
+  br i1 %C, label %l_bad, label %for.body
+
+for.body:                                         ; preds = %for.cond
+  indirectbr i8* %P, [label %for.inc, label %l_bad]
+
+for.inc:                                          ; preds = %for.body
+  br label %for.cond
+
+l_bad:                                            ; preds = %for.body, %for.cond
+  ret void
+}