From fd0a5478a19823e836207b4b7900f567bc608dbd Mon Sep 17 00:00:00 2001
From: Chris Lattner <sabre@nondot.org>
Date: Mon, 1 May 2006 22:03:24 +0000
Subject: [PATCH] Fix a latent bug that my spiller patch last week exposed: we
 were leaving instructions in the virtregfolded map that were deleted. 
 Because they were deleted, newly allocated instructions could end up at the
 same address, magically finding themselves in the map.  The solution is to
 remove entries from the map when we delete the instructions.

llvm-svn: 28041
---
 llvm/lib/CodeGen/VirtRegMap.cpp | 4 ++++
 llvm/lib/CodeGen/VirtRegMap.h   | 7 +++----
 2 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/llvm/lib/CodeGen/VirtRegMap.cpp b/llvm/lib/CodeGen/VirtRegMap.cpp
index fa5a6ac8e807..912359d13755 100644
--- a/llvm/lib/CodeGen/VirtRegMap.cpp
+++ b/llvm/lib/CodeGen/VirtRegMap.cpp
@@ -730,6 +730,7 @@ void LocalSpiller::RewriteMBB(MachineBasicBlock &MBB, VirtRegMap &VRM) {
           assert(VirtRegMap::isMod && "Can't be modref!");
           DEBUG(std::cerr << "Removed dead store:\t" << *MDSI->second);
           MBB.erase(MDSI->second);
+          VRM.RemoveFromFoldedVirtMap(MDSI->second);
           MaybeDeadStores.erase(MDSI);
           ++NumDSE;
         }
@@ -791,6 +792,7 @@ void LocalSpiller::RewriteMBB(MachineBasicBlock &MBB, VirtRegMap &VRM) {
               ++NumDCE;
               DEBUG(std::cerr << "Removing now-noop copy: " << MI);
               MBB.erase(&MI);
+              VRM.RemoveFromFoldedVirtMap(&MI);
               goto ProcessNextInst;
             }
             Spills.ClobberPhysReg(VirtReg);
@@ -825,6 +827,7 @@ void LocalSpiller::RewriteMBB(MachineBasicBlock &MBB, VirtRegMap &VRM) {
             ++NumDCE;
             DEBUG(std::cerr << "Removing now-noop copy: " << MI);
             MBB.erase(&MI);
+            VRM.RemoveFromFoldedVirtMap(&MI);
             goto ProcessNextInst;
           }
         }
@@ -835,6 +838,7 @@ void LocalSpiller::RewriteMBB(MachineBasicBlock &MBB, VirtRegMap &VRM) {
           DEBUG(std::cerr << "Removed dead store:\t" << *LastStore);
           ++NumDSE;
           MBB.erase(LastStore);
+          VRM.RemoveFromFoldedVirtMap(LastStore);
         }
         LastStore = next(MII);
 
diff --git a/llvm/lib/CodeGen/VirtRegMap.h b/llvm/lib/CodeGen/VirtRegMap.h
index 898677e8f929..83d5aada473f 100644
--- a/llvm/lib/CodeGen/VirtRegMap.h
+++ b/llvm/lib/CodeGen/VirtRegMap.h
@@ -137,11 +137,10 @@ namespace llvm {
       return MI2VirtMap.equal_range(MI);
     }
     
-    /// RemoveFromFoldedVirtMap - Given a machine instruction in the folded
-    /// instruction map, remove the entry in the folded instruction map.
+    /// RemoveFromFoldedVirtMap - If the specified machine instruction is in
+    /// the folded instruction map, remove its entry from the map.
     void RemoveFromFoldedVirtMap(MachineInstr *MI) {
-      bool ErasedAny = MI2VirtMap.erase(MI);
-      assert(ErasedAny && "Machine instr not in folded vreg map!");
+      MI2VirtMap.erase(MI);
     }
 
     void print(std::ostream &OS) const;