From 5c03a6b8f59399d524621600e845b7715b7ce969 Mon Sep 17 00:00:00 2001
From: Evan Cheng <evan.cheng@apple.com>
Date: Thu, 12 Jan 2012 20:31:24 +0000
Subject: 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

llvm-svn: 148043
---
 llvm/lib/CodeGen/BranchFolding.cpp | 5 +++++
 1 file changed, 5 insertions(+)

(limited to 'llvm/lib/CodeGen/BranchFolding.cpp')

diff --git a/llvm/lib/CodeGen/BranchFolding.cpp b/llvm/lib/CodeGen/BranchFolding.cpp
index 89894c37ee0..793e4f07063 100644
--- a/llvm/lib/CodeGen/BranchFolding.cpp
+++ b/llvm/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)
-- 
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