Never extend live ranges for <undef> uses.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135886 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/SplitKit.cpp b/lib/CodeGen/SplitKit.cpp
index 46a43d8bd72038f2362942148649b0b3610e4eb1..2197046b030b2dc0208eb220f24b96190e2c88ea 100644 (file)
--- a/lib/CodeGen/SplitKit.cpp
+++ b/lib/CodeGen/SplitKit.cpp
@@ -952,7 +952,7 @@ void SplitEditor::rewriteAssigned(bool ExtendRanges) {
                  << Idx << ':' << RegIdx << '\t' << *MI);
 
     // Extend liveness to Idx if the instruction reads reg.
-    if (!ExtendRanges)
+    if (!ExtendRanges || MO.isUndef())
       continue;
 
     // Skip instructions that don't read Reg.