InstCombineSimplifyDemanded: Remove nsw/nuw flags when optimizing demanded bits

[oota-llvm.git] / lib / CodeGen / MachineCopyPropagation.cpp

diff --git a/lib/CodeGen/MachineCopyPropagation.cpp b/lib/CodeGen/MachineCopyPropagation.cpp
index 8ee97e90a747bf5f4dd949fc1e4c85ebb76dd426..43c80b7c21bf419ff21b98c74c0897df2667bc1b 100644 (file)
--- a/lib/CodeGen/MachineCopyPropagation.cpp
+++ b/lib/CodeGen/MachineCopyPropagation.cpp
@@ -75,10 +75,9 @@ MachineCopyPropagation::SourceNoLongerAvailable(unsigned Reg,
            I != E; ++I) {
         unsigned MappedDef = *I;
         // Source of copy is no longer available for propagation.
-        if (AvailCopyMap.erase(MappedDef)) {
-          for (MCSubRegIterator SR(MappedDef, TRI); SR.isValid(); ++SR)
-            AvailCopyMap.erase(*SR);
-        }
+        AvailCopyMap.erase(MappedDef);
+        for (MCSubRegIterator SR(MappedDef, TRI); SR.isValid(); ++SR)
+          AvailCopyMap.erase(*SR);
       }
     }
   }
@@ -253,7 +252,11 @@ bool MachineCopyPropagation::CopyPropagateBlock(MachineBasicBlock &MBB) {
         report_fatal_error("MachineCopyPropagation should be run after"
                            " register allocation!");
 
-      if (MO.isDef()) {
+      // Treat undef use like defs.
+      // The backends are allowed to do whatever they want with undef value
+      // and we cannot be sure this register will not be rewritten to break
+      // some false dependencies for the hardware for instance.
+      if (MO.isDef() || MO.isUndef()) {
         Defs.push_back(Reg);
         continue;
       }
@@ -336,8 +339,8 @@ bool MachineCopyPropagation::runOnMachineFunction(MachineFunction &MF) {
 
   bool Changed = false;
 
-  TRI = MF.getTarget().getSubtargetImpl()->getRegisterInfo();
-  TII = MF.getTarget().getSubtargetImpl()->getInstrInfo();
+  TRI = MF.getSubtarget().getRegisterInfo();
+  TII = MF.getSubtarget().getInstrInfo();
   MRI = &MF.getRegInfo();
 
   for (MachineFunction::iterator I = MF.begin(), E = MF.end(); I != E; ++I)