PostRA scheduler fix. Clear stale loop dependencies.

atrick · atrick · commit 35c9e5121994 · 2011-10-07T06:33:09.000Z
Fixes &lt;rdar://problem/10235725&gt;

llvm-svn: 141357
diff --git a/llvm/lib/CodeGen/ScheduleDAGInstrs.cpp b/llvm/lib/CodeGen/ScheduleDAGInstrs.cpp
@@ -134,6 +134,7 @@ static const Value *getUnderlyingObjectForInstr(const MachineInstr *MI,
 }
 
 void ScheduleDAGInstrs::StartBlock(MachineBasicBlock *BB) {
+  LoopRegs.Deps.clear();
   if (MachineLoop *ML = MLI.getLoopFor(BB))
     if (BB == ML->getLoopLatch()) {
       MachineBasicBlock *Header = ML->getHeader();
diff --git a/llvm/lib/CodeGen/ScheduleDAGInstrs.h b/llvm/lib/CodeGen/ScheduleDAGInstrs.h
@@ -48,7 +48,8 @@ namespace llvm {
     /// VisitLoop - Clear out any previous state and analyze the given loop.
     ///
     void VisitLoop(const MachineLoop *Loop) {
-      Deps.clear();
+      assert(Deps.empty() && "stale loop dependencies");
+
       MachineBasicBlock *Header = Loop->getHeader();
       SmallSet<unsigned, 8> LoopLiveIns;
       for (MachineBasicBlock::livein_iterator LI = Header->livein_begin(),

Original file line number	Diff line number	Diff line change
`@@ -134,6 +134,7 @@ static const Value getUnderlyingObjectForInstr(const MachineInstr MI,`
`134`	`134`	`}`
`135`	`135`
`136`	`136`	`void ScheduleDAGInstrs::StartBlock(MachineBasicBlock *BB) {`
	`137`	`+ LoopRegs.Deps.clear();`
`137`	`138`	`if (MachineLoop *ML = MLI.getLoopFor(BB))`
`138`	`139`	`if (BB == ML->getLoopLatch()) {`
`139`	`140`	`MachineBasicBlock *Header = ML->getHeader();`