Revert "CodeGen: Simplify CodeGenFunction::EmitCaseStmt"

I misunderstood the discussion on this. The complexity here is
justified by the malloc overhead it saves.

This reverts commit r199302.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@199700 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 23 insertions, 0 deletions

diff --git a/lib/CodeGen/CGCleanup.cpp b/lib/CodeGen/CGCleanup.cpp
index 4983ce9343..3cf21bb9c3 100644
--- a/lib/CodeGen/CGCleanup.cpp
+++ b/lib/CodeGen/CGCleanup.cpp
@@ -885,6 +885,29 @@ void CodeGenFunction::PopCleanupBlock(bool FallthroughIsBranchThrough) {
   }
 }
 
+/// isObviouslyBranchWithoutCleanups - Return true if a branch to the
+/// specified destination obviously has no cleanups to run.  'false' is always
+/// a conservatively correct answer for this method.
+bool CodeGenFunction::isObviouslyBranchWithoutCleanups(JumpDest Dest) const {
+  assert(Dest.getScopeDepth().encloses(EHStack.stable_begin())
+         && "stale jump destination");
+  
+  // Calculate the innermost active normal cleanup.
+  EHScopeStack::stable_iterator TopCleanup =
+    EHStack.getInnermostActiveNormalCleanup();
+  
+  // If we're not in an active normal cleanup scope, or if the
+  // destination scope is within the innermost active normal cleanup
+  // scope, we don't need to worry about fixups.
+  if (TopCleanup == EHStack.stable_end() ||
+      TopCleanup.encloses(Dest.getScopeDepth())) // works for invalid
+    return true;
+
+  // Otherwise, we might need some cleanups.
+  return false;
+}
+
+
 /// Terminate the current block by emitting a branch which might leave
 /// the current cleanup-protected scope.  The target scope may not yet
 /// be known, in which case this will require a fixup.