Implement SimplifyCFG/2003-08-17-FoldSwitch.ll:test5
llvm-svn: 8093
diff --git a/llvm/lib/Transforms/Utils/Local.cpp b/llvm/lib/Transforms/Utils/Local.cpp
index e668dc3..52973f8 100644
--- a/llvm/lib/Transforms/Utils/Local.cpp
+++ b/llvm/lib/Transforms/Utils/Local.cpp
@@ -80,6 +80,9 @@
// single branch instruction!
ConstantInt *CI = dyn_cast<ConstantInt>(SI->getCondition());
BasicBlock *TheOnlyDest = SI->getSuccessor(0); // The default dest
+ BasicBlock *DefaultDest = TheOnlyDest;
+ assert(TheOnlyDest == SI->getDefaultDest() &&
+ "Default destination is not successor #0?");
// Figure out which case it goes to...
for (unsigned i = 1, e = SI->getNumSuccessors(); i != e; ++i) {
@@ -89,6 +92,16 @@
break;
}
+ // Check to see if this branch is going to the same place as the default
+ // dest. If so, eliminate it as an explicit compare.
+ if (SI->getSuccessor(i) == DefaultDest) {
+ // Remove this entry...
+ DefaultDest->removePredecessor(SI->getParent());
+ SI->removeCase(i);
+ --i; --e; // Don't skip an entry...
+ continue;
+ }
+
// Otherwise, check to see if the switch only branches to one destination.
// We do this by reseting "TheOnlyDest" to null when we find two non-equal
// destinations.