[llvm-commits] [llvm] r86172 - /llvm/trunk/lib/CodeGen/AggressiveAntiDepBreaker.cpp

[David Goodwin]

Author: david_goodwin
Date: Thu Nov  5 15:06:09 2009
New Revision: 86172

URL: http://llvm.org/viewvc/llvm-project?rev=86172&view=rev
Log:
Fix bug in aggressive antidep breaking; liveness was not updated correctly for regions that do not have antidep candidates.

Modified:
    llvm/trunk/lib/CodeGen/AggressiveAntiDepBreaker.cpp

Modified: llvm/trunk/lib/CodeGen/AggressiveAntiDepBreaker.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AggressiveAntiDepBreaker.cpp?rev=86172&r1=86171&r2=86172&view=diff

==============================================================================
--- llvm/trunk/lib/CodeGen/AggressiveAntiDepBreaker.cpp (original)
+++ llvm/trunk/lib/CodeGen/AggressiveAntiDepBreaker.cpp Thu Nov  5 15:06:09 2009
@@ -630,12 +630,6 @@
   std::multimap<unsigned, AggressiveAntiDepState::RegisterReference>& 
     RegRefs = State->GetRegRefs();
 
-  // Nothing to do if no candidates.
-  if (Candidates.empty()) {
-    DEBUG(errs() << "\n===== No anti-dependency candidates\n");
-    return 0;
-  }
-
   // The code below assumes that there is at least one instruction,
   // so just duck out immediately if the block is empty.
   if (SUnits.empty()) return 0;
@@ -655,16 +649,19 @@
 
   // ...need a map from MI to SUnit.
   std::map<MachineInstr *, SUnit *> MISUnitMap;
-
-  DEBUG(errs() << "\n===== Attempting to break " << Candidates.size() << 
-        " anti-dependencies\n");
   for (unsigned i = 0, e = SUnits.size(); i != e; ++i) {
     SUnit *SU = &SUnits[i];
     MISUnitMap.insert(std::pair<MachineInstr *, SUnit *>(SU->getInstr(), SU));
   }
 
+  // Even if there are no anti-dependencies we still need to go
+  // through the instructions to update Def, Kills, etc.
 #ifndef NDEBUG 
-  {
+  if (Candidates.empty()) {
+    DEBUG(errs() << "\n===== No anti-dependency candidates\n");
+  } else {
+    DEBUG(errs() << "\n===== Attempting to break " << Candidates.size() << 
+          " anti-dependencies\n");
     DEBUG(errs() << "Available regs:");
     for (unsigned Reg = 0; Reg < TRI->getNumRegs(); ++Reg) {
       if (!State->IsLive(Reg))