Avoid finding loop back edges when we are not splitting critical edges in

CodeGenPrepare (which is the default behavior).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122801 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/Scalar/CodeGenPrepare.cpp b/lib/Transforms/Scalar/CodeGenPrepare.cpp
index f4edcc76ec532620e043852b56802ebb01495da7..8df0b3ce47a265534380f8f34114289200fc3c96 100644 (file)
--- a/lib/Transforms/Scalar/CodeGenPrepare.cpp
+++ b/lib/Transforms/Scalar/CodeGenPrepare.cpp
@@ -119,8 +119,10 @@ bool CodeGenPrepare::runOnFunction(Function &F) {
   // unconditional branch.
   EverMadeChange |= EliminateMostlyEmptyBlocks(F);
 
-  // Now find loop back edges.
-  findLoopBackEdges(F);
+  // Now find loop back edges, but only if they are being used to decide which
+  // critical edges to split.
+  if (CriticalEdgeSplit)
+    findLoopBackEdges(F);
 
   bool MadeChange = true;
   while (MadeChange) {