From: Jakob Stoklund Olesen <stoklund@2pi.dk>
Date: Wed, 16 Mar 2011 22:56:13 +0000 (+0000)
Subject: Erase virtual registers that are unused after DCE.
X-Git-Url: http://plrg.eecs.uci.edu/git/?a=commitdiff_plain;h=cc5c4296fda7270e8394626d7254596f5f9c8d82;p=oota-llvm.git

Erase virtual registers that are unused after DCE.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127773 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/CodeGen/LiveRangeEdit.cpp b/lib/CodeGen/LiveRangeEdit.cpp
index 0769f95262d..e994d8c32d4 100644
--- a/lib/CodeGen/LiveRangeEdit.cpp
+++ b/lib/CodeGen/LiveRangeEdit.cpp
@@ -174,13 +174,21 @@ void LiveRangeEdit::eliminateDeadDefs(SmallVectorImpl<MachineInstr*> &Dead,
         if (!TargetRegisterInfo::isVirtualRegister(Reg))
           continue;
         LiveInterval &LI = LIS.getInterval(Reg);
-        // Remove defined value.
-        if (MOI->isDef())
-          if (VNInfo *VNI = LI.getVNInfoAt(Idx))
-            LI.removeValNo(VNI);
+
         // Shrink read registers.
         if (MI->readsVirtualRegister(Reg))
           ToShrink.insert(&LI);
+
+        // Remove defined value.
+        if (MOI->isDef()) {
+          if (VNInfo *VNI = LI.getVNInfoAt(Idx)) {
+            LI.removeValNo(VNI);
+            if (LI.empty()) {
+              ToShrink.remove(&LI);
+              eraseVirtReg(Reg, LIS);
+            }
+          }
+        }
       }
 
       if (delegate_)