Doh. Machine LICM is re-initializing the CSE map over and over. Patch by Anna Zaks. rdar://8037934.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@105065 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/MachineLICM.cpp b/lib/CodeGen/MachineLICM.cpp
index 6120617..d9623ab 100644
--- a/lib/CodeGen/MachineLICM.cpp
+++ b/lib/CodeGen/MachineLICM.cpp
@@ -62,6 +62,7 @@
// State that is updated as we process loops
bool Changed; // True if a loop is changed.
+ bool FirstInLoop; // True if it's the first LICM in the loop.
MachineLoop *CurLoop; // The current loop we are working on.
MachineBasicBlock *CurPreheader; // The preheader for CurLoop.
@@ -207,7 +208,7 @@
else
DEBUG(dbgs() << "******** Post-regalloc Machine LICM ********\n");
- Changed = false;
+ Changed = FirstInLoop = false;
TM = &MF.getTarget();
TII = TM->getInstrInfo();
TRI = TM->getRegisterInfo();
@@ -244,6 +245,7 @@
// CSEMap is initialized for loop header when the first instruction is
// being hoisted.
MachineDomTreeNode *N = DT->getNode(CurLoop->getHeader());
+ FirstInLoop = true;
HoistRegion(N);
CSEMap.clear();
}
@@ -776,7 +778,10 @@
// If this is the first instruction being hoisted to the preheader,
// initialize the CSE map with potential common expressions.
- InitCSEMap(CurPreheader);
+ if (FirstInLoop) {
+ InitCSEMap(CurPreheader);
+ FirstInLoop = false;
+ }
// Look for opportunity to CSE the hoisted instruction.
unsigned Opcode = MI->getOpcode();