Use std::stable_sort instead of std::sort when sorting stack slots

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

diff --git a/lib/CodeGen/StackColoring.cpp b/lib/CodeGen/StackColoring.cpp
index 3150f3dfaa85aa865b88f9ec3f2217fe4c402019..e306a2f2c20e6df3aa4dbcdb5692a41452a94059 100644 (file)
--- a/lib/CodeGen/StackColoring.cpp
+++ b/lib/CodeGen/StackColoring.cpp
@@ -261,7 +261,7 @@ unsigned StackColoring::collectMarkers(unsigned NumSlot) {
 
       MarkersFound++;
 
-      const Value *Allocation = MFI->getObjectAllocation(Slot);
+      const AllocaInst *Allocation = MFI->getObjectAllocation(Slot);
       if (Allocation) {
         DEBUG(dbgs()<<"Found a lifetime marker for slot #"<<Slot<<
               " with allocation: "<< Allocation->getName()<<"\n");
@@ -481,11 +481,11 @@ void StackColoring::remapInstructions(DenseMap<int, int> &SlotRemap) {
   }
 
   // Keep a list of *allocas* which need to be remapped.
-  DenseMap<const Value*, const Value*> Allocas;
+  DenseMap<const AllocaInst*, const AllocaInst*> Allocas;
   for (DenseMap<int, int>::iterator it = SlotRemap.begin(),
        e = SlotRemap.end(); it != e; ++it) {
-    const Value *From = MFI->getObjectAllocation(it->first);
-    const Value *To = MFI->getObjectAllocation(it->second);
+    const AllocaInst *From = MFI->getObjectAllocation(it->first);
+    const AllocaInst *To = MFI->getObjectAllocation(it->second);
     assert(To && From && "Invalid allocation object");
     Allocas[From] = To;
   }
@@ -515,10 +515,17 @@ void StackColoring::remapInstructions(DenseMap<int, int> &SlotRemap) {
         V = GetUnderlyingObject(V);
         // If we did not find one, or if the one that we found is not in our
         // map, then move on.
-        if (!V || !Allocas.count(V))
+        if (!V || !isa<AllocaInst>(V)) {
+          // Clear mem operand since we don't know for sure that it doesn't
+          // alias a merged alloca.
+          MMO->setValue(0);
+          continue;
+        }
+        const AllocaInst *AI= cast<AllocaInst>(V);
+        if (!Allocas.count(AI))
           continue;
 
-        MMO->setValue(Allocas[V]);
+        MMO->setValue(Allocas[AI]);
         FixedMemOp++;
       }
 
@@ -713,7 +720,9 @@ bool StackColoring::runOnMachineFunction(MachineFunction &Func) {
   // and continue.
 
   // Sort the slots according to their size. Place unused slots at the end.
-  std::sort(SortedSlots.begin(), SortedSlots.end(), SlotSizeSorter(MFI));
+  // Use stable sort to guarantee deterministic code generation.
+  std::stable_sort(SortedSlots.begin(), SortedSlots.end(),
+                   SlotSizeSorter(MFI));
 
   bool Chanded = true;
   while (Chanded) {