From 30a343aeedf777f9b8b6be9823da750afbf765b1 Mon Sep 17 00:00:00 2001
From: Evan Cheng <evan.cheng@apple.com>
Date: Fri, 7 Jan 2011 21:08:26 +0000
Subject: [PATCH] DBG_VALUE does not have any side effects; it also makes no
 sense to mark it cheap as a copy.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123031 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/Target/Target.td     | 2 +-
 lib/CodeGen/MachineInstr.cpp      | 4 +++-
 lib/CodeGen/PeepholeOptimizer.cpp | 4 +++-
 lib/CodeGen/VirtRegRewriter.cpp   | 3 ++-
 4 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/include/llvm/Target/Target.td b/include/llvm/Target/Target.td
index f7a029bd611..e88a09eecc6 100644
--- a/include/llvm/Target/Target.td
+++ b/include/llvm/Target/Target.td
@@ -484,7 +484,7 @@ def DBG_VALUE : Instruction {
   let OutOperandList = (outs);
   let InOperandList = (ins variable_ops);
   let AsmString = "DBG_VALUE";
-  let isAsCheapAsAMove = 1;
+  let neverHasSideEffects = 1;
 }
 def REG_SEQUENCE : Instruction {
   let OutOperandList = (outs unknown:$dst);
diff --git a/lib/CodeGen/MachineInstr.cpp b/lib/CodeGen/MachineInstr.cpp
index bc2a545a5f2..ccb2ffbab1d 100644
--- a/lib/CodeGen/MachineInstr.cpp
+++ b/lib/CodeGen/MachineInstr.cpp
@@ -1115,7 +1115,9 @@ bool MachineInstr::isSafeToMove(const TargetInstrInfo *TII,
     SawStore = true;
     return false;
   }
-  if (TID->isTerminator() || TID->hasUnmodeledSideEffects())
+
+  if (isLabel() || isDebugValue() ||
+      TID->isTerminator() || TID->hasUnmodeledSideEffects())
     return false;
 
   // See if this instruction does a load.  If so, we have to guarantee that the
diff --git a/lib/CodeGen/PeepholeOptimizer.cpp b/lib/CodeGen/PeepholeOptimizer.cpp
index 07c2b80dcb0..1ddfe8b7c23 100644
--- a/lib/CodeGen/PeepholeOptimizer.cpp
+++ b/lib/CodeGen/PeepholeOptimizer.cpp
@@ -336,7 +336,9 @@ bool PeepholeOptimizer::runOnMachineFunction(MachineFunction &MF) {
       MachineInstr *MI = &*MII++;
       LocalMIs.insert(MI);
 
-      if (MI->getDesc().hasUnmodeledSideEffects())
+      if (MI->isLabel() || MI->isPHI() || MI->isImplicitDef() ||
+          MI->isKill() || MI->isInlineAsm() || MI->isDebugValue() ||
+          MI->getDesc().hasUnmodeledSideEffects())
         continue;
 
       if (MI->getDesc().isCompare()) {
diff --git a/lib/CodeGen/VirtRegRewriter.cpp b/lib/CodeGen/VirtRegRewriter.cpp
index 14ee69da4c2..d04b9285bab 100644
--- a/lib/CodeGen/VirtRegRewriter.cpp
+++ b/lib/CodeGen/VirtRegRewriter.cpp
@@ -1620,7 +1620,8 @@ static bool isSafeToDelete(MachineInstr &MI) {
   const TargetInstrDesc &TID = MI.getDesc();
   if (TID.mayLoad() || TID.mayStore() || TID.isCall() || TID.isTerminator() ||
       TID.isCall() || TID.isBarrier() || TID.isReturn() ||
-      TID.hasUnmodeledSideEffects())
+      TID.hasUnmodeledSideEffects() ||
+      MI.isLabel() || MI.isDebugValue())
     return false;
   for (unsigned i = 0, e = MI.getNumOperands(); i != e; ++i) {
     MachineOperand &MO = MI.getOperand(i);
-- 
2.34.1