[llvm-commits] [llvm] r105065 - /llvm/trunk/lib/CodeGen/MachineLICM.cpp

[Evan Cheng]

Author: evancheng
Date: Fri May 28 19:06:36 2010
New Revision: 105065

URL: http://llvm.org/viewvc/llvm-project?rev=105065&view=rev
Log:
Doh. Machine LICM is re-initializing the CSE map over and over. Patch by Anna Zaks. rdar://8037934.

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

Modified: llvm/trunk/lib/CodeGen/MachineLICM.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/MachineLICM.cpp?rev=105065&r1=105064&r2=105065&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/MachineLICM.cpp (original)
+++ llvm/trunk/lib/CodeGen/MachineLICM.cpp Fri May 28 19:06:36 2010
@@ -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();