Revert commit 66140 since it caused several failures

in the Ada testcase.  Reverting this only covers up
the real problem, which is a nasty conceptual difficulty
in the phi elimination pass: when eliminating phi nodes
in landing pads, the register copies need to come before
the invoke, not at the end of the basic block which is
too late...  See PR3784.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@66826 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Transforms/Scalar/CodeGenPrepare.cpp

@@ -327,12 +327,6 @@ static void SplitEdgeNicely(TerminatorInst *TI, unsigned SuccNum,
   assert(isa<PHINode>(Dest->begin()) &&
          "This should only be called if Dest has a PHI!");
 
-  // Do not split edges to EH landing pads.
-  if (InvokeInst *Invoke = dyn_cast<InvokeInst>(TI)) {
-    if (Invoke->getSuccessor(1) == Dest)
-      return;
-  }
-
   // As a hack, never split backedges of loops.  Even though the copy for any
   // PHIs inserted on the backedge would be dead for exits from the loop, we
   // assume that the cost of *splitting* the backedge would be too high.

test/CodeGen/X86/split-eh-lpad-edges.ll

@@ -1,5 +1,6 @@
 ; RUN: llvm-as < %s | llc -mtriple=x86_64-apple-darwin | not grep jmp
 ; rdar://6647639
+; XFAIL: *
 
 	%struct.FetchPlanHeader = type { i8*, i8*, i32, i8*, i8*, i8*, i8*, i8*, %struct.NSObject* (%struct.NSObject*, %struct.objc_selector*, ...)*, %struct.__attributeDescriptionFlags }
 	%struct.NSArray = type { %struct.NSObject }