Build breaks

Download code from http://llvm.org/releases/download.html#3.4

and did
…/llvm/configure --enable-optimized --enable-assertions=no --enable-werror=yes --enable-targets=x86_64

and compilation breaks at following place,

This will not be there if
.–enable-werror is removed as expected, Just informing in case some body want to fix

llvm[2]: Compiling CostModel.cpp for Release build
cc1plus: warnings being treated as errors
/home/deleisha/CodeSpace/llvmDev/llvm/lib/Analysis/CostModel.cpp: In function âbool matchPairwiseReductionAtLevel(const llvm::BinaryOperator*, unsigned int, unsigned int)â:
/home/deleisha/CodeSpace/llvmDev/llvm/lib/Analysis/CostModel.cpp:208: error: comparison between signed and unsigned integer expressions
/home/deleisha/CodeSpace/llvmDev/llvm/lib/Analysis/CostModel.cpp: In function âbool matchVectorSplittingReduction(const llvm::ExtractElementInst*, unsigned int&, llvm::Type*&)â:
/home/deleisha/CodeSpace/llvmDev/llvm/lib/Analysis/CostModel.cpp:335: error: comparison between signed and unsigned integer expressions
make[2]: *** [/home/deleisha/CodeSpace/llvmDev/build/lib/Analysis/Release/CostModel.o] Error 1
make[2]: Leaving directory /home/deleisha/CodeSpace/llvmDev/build/lib/Analysis' make[1]: *** [Analysis/.makeall] Error 2 make[1]: Leaving directory /home/deleisha/CodeSpace/llvmDev/build/lib’
make: *** [all] Error 1
[root@localhost build]#