When hoisting common code, watch out for uses which are marked "kill". If the

killed registers are needed below the insertion point, then unset the kill
marker.

Sorry I'm not able to find a reduced test case.

rdar://10660944

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@148043 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/BranchFolding.cpp b/lib/CodeGen/BranchFolding.cpp
index 89894c37ee0e629718783050ad0344e8583e7c4f..793e4f07063680488a5241d9e6e456243a3a3c48 100644 (file)
--- a/lib/CodeGen/BranchFolding.cpp
+++ b/lib/CodeGen/BranchFolding.cpp
@@ -1618,6 +1618,11 @@ bool BranchFolder::HoistCommonCodeInSuccs(MachineBasicBlock *MBB) {
           IsSafe = false;
           break;
         }
+
+        if (MO.isKill() && Uses.count(Reg))
+          // Kills a register that's read by the instruction at the point of
+          // insertion. Remove the kill marker.
+          MO.setIsKill(false);
       }
     }
     if (!IsSafe)