Speedup debug builds a bit


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@15137 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/LiveIntervalAnalysis.h b/lib/CodeGen/LiveIntervalAnalysis.h
index 4e2cbeb..bb324e3 100644
--- a/lib/CodeGen/LiveIntervalAnalysis.h
+++ b/lib/CodeGen/LiveIntervalAnalysis.h
@@ -95,8 +95,9 @@
         virtual bool runOnMachineFunction(MachineFunction&);
 
         LiveInterval& getInterval(unsigned reg) {
-            assert(r2iMap_.count(reg)&& "Interval does not exist for register");
-            return *r2iMap_.find(reg)->second;
+          Reg2IntervalMap::iterator I = r2iMap_.find(reg);
+            assert(I != r2iMap_.end()&& "Interval does not exist for register");
+            return *I->second;
         }
 
         /// getInstructionIndex - returns the base index of instr