[llvm-commits] [llvm] r44005 - /llvm/trunk/include/llvm/CodeGen/BreakCriticalMachineEdge.h

[Owen Anderson]

Author: resistor
Date: Sun Nov 11 20:13:07 2007
New Revision: 44005

URL: http://llvm.org/viewvc/llvm-project?rev=44005&view=rev
Log:
Fix rewriting of PHI nodes.

Could someone more familiar with machine-level stuff review this for me?

Modified:
    llvm/trunk/include/llvm/CodeGen/BreakCriticalMachineEdge.h

Modified: llvm/trunk/include/llvm/CodeGen/BreakCriticalMachineEdge.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/CodeGen/BreakCriticalMachineEdge.h?rev=44005&r1=44004&r2=44005&view=diff

==============================================================================
--- llvm/trunk/include/llvm/CodeGen/BreakCriticalMachineEdge.h (original)
+++ llvm/trunk/include/llvm/CodeGen/BreakCriticalMachineEdge.h Sun Nov 11 20:13:07 2007
@@ -52,16 +52,27 @@
       break;
     }
     
-    // Scan the operands of this branch, replacing any uses of dst with
-    // crit_mbb.
+    // Scan the operands of this branch, finding all uses of this MBB
+    std::vector<unsigned> toRemove;
+    unsigned reg = 0;
     for (unsigned i = 0, e = mii->getNumOperands(); i != e; ++i) {
       MachineOperand & mo = mii->getOperand(i);
       if (mo.isMachineBasicBlock() &&
-          mo.getMachineBasicBlock() == dst) {
-        found_branch = true;
-        mo.setMachineBasicBlock(crit_mbb);
-      }
+          mo.getMachineBasicBlock() == dst)
+        reg = mii->getOperand(i-1).getReg();
+        toRemove.push_back(i-1);
     }
+    
+    // Remove all uses of this MBB
+    for (std::vector<unsigned>::reverse_iterator I = toRemove.rbegin(),
+         E = toRemove.rend(); I != E; ++I) {
+      mii->RemoveOperand(*I+1);
+      mii->RemoveOperand(*I);
+    }
+    
+    // Add a single use corresponding to the new MBB
+    mii->addRegOperand(reg, false);
+    mii->addMachineBasicBlockOperand(crit_mbb);
   }
 
   // TODO: This is tentative. It may be necessary to fix this code. Maybe