IfConversion: Don't count branches in # of duplicates.

[iteratee]

Summary

If the entire blocks match, we would count the branch instructions
toward the number of duplicated instructions. This doesn't match what we
do elsewhere, and was causing a bug.

[hfinkel]

LGTM (does indeed match what we do later in the same function)

[iteratee]

lib/CodeGen/IfConversion.cpp

675

Heh, Shows what I get for copy and paste.
Should be TIB.

[Eugene.Zelenko]

Committed in rL280448. Please specify "Differential revision: <URL>" in commit message.

lib/CodeGen/IfConversion.cpp

if(skipDebugInstructionsForward(FIB, FIE))
       break;
     if (!TIB->isIdenticalTo(*FIB))
       break;
     // A pred-clobbering instruction in the shared portion prevents
     // if-conversion.
     std::vector<MachineOperand> PredDefs;
     if (TII->DefinesPredicate(*TIB, PredDefs))
       return false;
+    // If we get all the way to the branch instructions, don't count them.
+    if (!TIE->isBranch())
       ++Dups1;
     ++TIB;
     ++FIB;
   }
 
   // Check for already containing all of the block.
   if (TIB == TIE || FIB == FIE)
     return true;
   // Now, in preparation for counting duplicate instructions at the ends of the