SelectBasicBlock is rather slow even when it doesn't do anything; skip the
unnecessary work where possible.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129763 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
index 8e599ae..af31888 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
@@ -1017,11 +1017,13 @@
else
++NumFastIselBlocks;
- // Run SelectionDAG instruction selection on the remainder of the block
- // not handled by FastISel. If FastISel is not run, this is the entire
- // block.
- bool HadTailCall;
- SelectBasicBlock(Begin, BI, HadTailCall);
+ if (Begin != BI) {
+ // Run SelectionDAG instruction selection on the remainder of the block
+ // not handled by FastISel. If FastISel is not run, this is the entire
+ // block.
+ bool HadTailCall;
+ SelectBasicBlock(Begin, BI, HadTailCall);
+ }
FinishBasicBlock();
FuncInfo->PHINodesToUpdate.clear();